PLEIOPLURIPOTENT STEM CELL PROGRAMMABLE GENE INSERTION 1. CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No.63/391,659, filed July 22, 2022 and U.S. Provisional Application No.63/375,190, filed September 9, 2022; each of which is hereby incorporated in its entirety by reference. 2. SEQUENCE LISTING [0002] The instant application contains a Sequence Listing with 667 sequences, which has been submitted via Patent Center and is hereby incorporated by reference in its entirety. Said XML copy, created on July 21, 2023 is named 52810PCT-sequencelisting.xml, and is 918,523 bytes in size. 3. BACKGROUND [0003] Programmable, efficient, and multiplexed genome integration of large, diverse DNA cargo independent of DNA repair remains an unsolved challenge of genome editing. Current gene integration approaches require double strand breaks that evoke DNA damage responses and rely on repair pathways that are inactive in terminally differentiated cells. Furthermore, CRISPR-based approaches that bypass double stranded breaks, such as Prime editing, are limited to modification or insertion of short sequences. [0004] There is a need in the art for techniques and gene editor compositions and gene editor guide RNAs which address and overcome these shortcomings and enable the programmable genomic integration of a large gene(s) in pluripotent stem cells. 4. SUMMARY [0005] This disclosure features a method of generating a pleiopluripotent cell, pleiopluripotent cells, pleiopluripotent-derived cells, and methods of using the same. In one aspect, this disclosure features a method of generating a pleiopluripotent cell, where the method includes site-specifically incorporating at least a first integration recognition site (e.g., AttB) into the genome of a pleiopluripotent cell, where site-specifically incorporating the genome of a pluripotent cell is effected by introducing into the pleiopluripotent stem cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein or a prime editor fusion protein or a polynucleotide encoding a prime editor fusion protein; (ii) at least a first pair of guide RNAs, wherein the first paired guide RNAs have domains that are capable of guiding the gene editor protein or prime
editor fusion protein to nick the pleiopluripotent stem cell genome at sites respectively flanking the specific incorporation site, and at least one of the first paired guide RNAs is an atgRNA that further includes a reverse transcriptase (RT) template that comprises at least a portion of the first integration recognition site, and the atgRNAs collectively encode the entirety of the first integration recognition site, whereby the first integration recognition site is site-specifically incorporated into the genome of the pleiopluripotent stem cell. In some embodiments, the first of the two paired guide RNAs is a first atgRNA that further includes a first RT template that comprises at least a portion of the first integration recognition site; and a second of the two paired guide RNAs is a second atgRNA that further includes a second RT template that comprises at least a portion of the first integration recognition site, wherein the first atgRNA and the second atgRNAs collectively encode the entirety of the first integration recognition site. [0006] In another aspect, the method includes integrating at least a first donor polynucleotide template into the pleiopluripotent cell genome at the first incorporated integration recognition site, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the at least one incorporated genomic integration recognition site by the integrase; thereby producing a second generation pleiopluripotent cell. [0007] In another aspect, this disclosure features a pleiopluripotent cell comprising at least a first integration recognition site site-specifically incorporated into the pleiopluripotent cell genome. In another aspect, this disclosure features a pleiopluripotent cell comprising a donor polynucleotide template comprised of one or more orthogonal integration recognition sites integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0008] In another aspect, this disclosure features a pleiopluripotent cell or a population thereof, where (i) the PC-derived cell is differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site incorporated site-specifically into the PC- derived cell genome. In another aspect, this disclosure features. [0009] In another aspect, this disclosure features a pleiopluripotent cell or a population thereof, wherein (i) the PC-derived cell is differentiated from a pleiopluripotent cell; and (ii) the PC- derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal
integration recognition site, integrated into the pleiopluripotent stem cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0010] The present disclosure provides nucleic acid compositions, methods, and an overall platform for site-specific genetic engineering using Programmable Addition via Site-Specific Targeting Elements (PASTE) (see Ionnidi et al.; Nat. Biotech.41: 500–512 (2023)); the entirety of which is incorporated herein by reference), transposon-mediated gene editing, or other suitable gene editing, or gene incorporation technology. Non-limiting examples of PASTE are also described in U.S. Pat. 11,572,556 and PCT Publication Nos. WO 2023/077148A1 and WO 2023/122764, each of which are hereby incorporated by reference in their entireties. [0011] In one aspect, this disclosure features a method of generating a pleiopluripotent cell, the method comprising: (a) site-specifically incorporating at least a first integration recognition site into a genome of a pleiopluripotent cell. In some embodiments of the methods, site-specifically incorporating the at least first integration recognition site is effected by introducing into the pleiopluripotent cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein or a prime editor fusion protein or a polynucleotide encoding a prime editor fusion protein; (ii) at least a first pair of guide RNAs, wherein the first paired guide RNAs have domains that are capable of guiding the gene editor protein or prime editor fusion protein to nick the pleiopluripotent cell genome at sites respectively flanking the specific incorporation site, and at least one of the two paired guide RNAs is an atgRNA that further includes a reverse transcriptase (RT) template that comprises at least a portion of the first integration recognition site, and the atgRNAs collectively encode the entirety of the first integration recognition site, whereby the first integration recognition site is site-specifically incorporated into the genome of the pleiopluripotent cell. [0012] In some embodiments, the at least first pair of guide RNAs comprise: (i) the first of the two paired guide RNAs is a first atgRNA that further includes a first RT template that comprises at least a portion of the first integration recognition site; and (ii) a second of the two paired guide RNAs is a second atgRNA that further includes a second RT template that comprises at least a portion of the first integration recognition site, wherein the first atgRNA and the second atgRNAs collectively encode the entirety of the first integration recognition site. [0013] In some embodiments of the methods, the at least first pair of guide RNAs comprise:
[0014] (i) the first of the two paired guide RNAs is an atgRNA that further includes an RT template that comprises at least a portion of the first integration recognition site, wherein the atgRNA encodes the entirety of the first integration recognition site; and [0015] (ii) a second of the two paired guide RNAs is a nicking gRNA. [0016] In some embodiments, the method further comprises incorporating a plurality of integration recognition sites. [0017] In some embodiments, the method further comprises: (b) integrating at least a first donor polynucleotide template into the pleiopluripotent cell genome at the first incorporated integration recognition site, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the at least one incorporated genomic integration recognition sites by the integrase; thereby producing a second generation pleiopluripotent cell. [0018] In some embodiments of the method, steps (a) and (b) are performed concurrently. [0019] In some embodiments of the method, step (a) is performed prior to step (b). [0020] In another aspect, this disclosure features a method of generating a pleiopluripotent cell, the method comprising: (a) integrating, into the genome of any of the pleiopluripotent cells described herein at the first incorporated recognition site, at least a first donor polynucleotide template, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the at least one incorporated genomic integration recognition sites by the integrase; thereby producing a second generation pleiopluripotent cell. [0021] In some embodiments, the method further comprises (b) site-specifically incorporating a second integration recognition site into the genome of the pleiopluripotent cell, thereby generating a third generation pleiopluripotent cell. [0022] In some embodiments, the method further comprises: (c) integrating a second donor polynucleotide template into the pleiopluripotent cell genome at the second incorporated integration recognition site, by delivering into the cell: (i) the second donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more integration
recognition sites orthogonal to the second integration recognition site, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the second incorporated genomic integration recognition sites by the integrase; thereby producing a fourth generation pleiopluripotent cell line. [0023] In some embodiments of the method, steps (a), (b), and (c) are performed concurrently. [0024] In some embodiments of the method, step (a) is performed prior to steps (b) and (c), wherein steps (b) and (c) are performed concurrently or step (b) is performed prior to step (c). [0025] In some embodiments of the method, the step of site-specifically incorporating the first integration recognition site and the step of site-specifically incorporating the second integration recognition site are performed concurrently. [0026] In some embodiments of the method, the first RT template encodes a first single-stranded DNA sequence and the second RT template encodes a second single-stranded DNA sequence. [0027] In some embodiments of the method, the first single-stranded DNA sequence comprises a complementary region with the first single-stranded DNA sequence. [0028] In some embodiments of the method, the first single-stranded DNA sequence and the first single-stranded DNA sequence form a duplex. [0029] In some embodiments of the method, the complementary region is 5 or more consecutive bases. [0030] In some embodiments of the method, the complementary region is 10 or more consecutive cases. [0031] In some embodiments of the method, the complementary region is 20 or more consecutive bases. [0032] In some embodiments of the method, the complementary region is 30 or more consecutive bases. [0033] In some embodiments of the method, at least one of the two paired guide RNAs has a chemical modification. [0034] In some embodiments of the method, the paired guide RNAs each have a chemical modification.
[0035] In some embodiments of the method, at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a safe harbor locus. [0036] In some embodiments of the method, at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent cell or a cell matured from the pleiopluripotent cell. [0037] In some embodiments of the method, at least one of the at least first integration recognition sites is incorporated into the genome at a plurality of loci, wherein disruption of at least one of the loci is capable of reducing allogeneic immune response to the pleiopluripotent cell or a cell matured from the pleiopluripotent cell. [0038] In some embodiments of the method, at least one of the at least first integration recognition sites is incorporated into the genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. [0039] In some embodiments of the method, the pleiopluripotent cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. In some embodiments of the method, the locus is in a chromosomal region selected from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. In some embodiments of the method, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, and RFXANK locus. In some embodiments of the method, the locus is the B2M locus. In some embodiments of the method, the locus is the CIITA locus. [0040] In some embodiments of the method, the introducing step is performed by electroporation. In some embodiments of the method, introducing comprises electroporating a gene editor protein or a polynucleotide encoding a gene editor protein, a prime editor fusion protein or a polynucleotide encoding a prime editor fusion protein, at least a first pair or guide RNAs, the donor polynucleotide template, or a combination thereof into the pleiopluripotent cell occurs using one or more of a recombinant adenovirus, helper dependent adenovirus, AAV, lentivirus, HSV, anellovirus, retrovirus, Doggybone DNA, minicircle, plasmid, miniDNA, nanoplasmid, exosome, fusosome, mRNA, RNP, or lipid nanoparticle.
[0041] In some embodiments of the method, the introducing step is performed by transfection. In some embodiments of the method, introducing comprises transfecting mRNA encoding the gene editor protein, the prime editor fusion protein, the at least first pair of guide gRNAs, the donor polynucleotide template, or a combination thereof into the pleiopluripotent cell, wherein the donor polynucleotide template is selected from a mini circle, a nanoplasmid, and a miniDNA. [0042] In some embodiments of the method, at least one of the at least first integration recognition sites is specific for a serine integrase. [0043] In some embodiments of the method, at least one of the at least first integration recognition sites is an attB or attP site. [0044] In some embodiments of the method, at least one of the at least first integration recognition sites is a modified attB or attP site. [0045] In some embodiments of the method, at least one of the at least first integration recognition sites is specific for BxB1 or a modified BxB1. [0046] In some embodiments of the method, at least one of the at least first integration recognition sites is comprised of 38 or 46 nucleotides. [0047] In some embodiments of the method, the first donor polynucleotide template encodes one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof. [0048] In some embodiments of the method, the inducing the at least one of the one or more inducible suicide genes targets the pleiopluripotent cell or a cell matured from the pleiopluripotent cell for cell death. [0049] In some embodiments of the method, expression of at least of the one or more inducible suicide gene is driven by a pluripotent stem cell-specific promoter. In some embodiments of the method, expression of at least one of the one or more inducible suicide gene is driven by a constitutive promoter. In some embodiments of the method, expression of at least one of the one or more inducible suicide gene is driven by an inducible promoter. [0050] In some embodiments of the method, the one or more inducible suicide genes is selected from: caspase9, cytosine deaminase, and thymidine kinase. In some embodiments of the method, the one or more inducible suicide genes is a controllable caspase9. In some embodiments of the
method, AP20187 (or an analog thereof) controls activity of Caspase9 or AP21967 (or an analog thereof) controls activity of Caspase9. In some embodiments, the method further comprises a second inducible suicide gene, wherein the second inducible suicide gene comprises a thymidine kinase. In some embodiments of the method, the polynucleotide encoding for the thymidine kinase is operably linked to the controllable capase9 protein using a 2A self-cleaving peptide or an internal ribosome entry site. [0051] In some embodiments of the method, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells. [0052] In some embodiments of the method, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells by inhibiting, blocking, or preventing recognition of the pleiopluripotent cell by macrophages, T- cells, Natural Killer (NK)-cells, antigen-presenting cells, or a combination thereof. [0053] In some embodiments of the method, the one or more exogenous polypeptides capable of modulating an immune response are capable of serving as a safety switch target. [0054] In some embodiments of the method, expression of at least one of the one or more exogenous polypeptides capable of modulating an immune response is driven by a pluripotent stem cell-specific promoter. [0055] In some embodiments of the method, expression of least one of the one or more exogenous polypeptides capable of modulating an immune response is driven by a constitutive promoter. [0056] In some embodiments of the method, expression of at least one of the one or more exogenous polypeptides capable of modulating an immune response is driven by an inducible promoter. [0057] In some embodiments of the method, the one or more exogenous polypeptides capable of modulating an immune response is selected from: CD47, PDL-1, B2M-HLA-E, HLA-G, HACD16, 41BBL, CD3, CD4, CD8, CD137, CD80, and A2AR. [0058] In some embodiments of the method, the donor polynucleotide template encodes a CD47 polypeptide, a PDL1 polypeptide, and a B2M-HLA-E polypeptide.
[0059] In some embodiments of the method, each of the sequences coding for CD47, PDL1 and B2M-HLA-E are separated by a sequence coding for a 2A self-cleaving peptide, an internal ribosome entry site, or a combination thereof. [0060] In some embodiments of the method, the donor polynucleotide template further comprises a polynucleotide sequence encoding a tag. [0061] In some embodiments of the method, the donor polynucleotide template further comprises an additional orthogonal integrase target recognition site. [0062] In some embodiments of the method, the second integration recognition site is site- specifically incorporated into a safe harbor locus. [0063] In some embodiments of the method, the second integration recognition site is different from the at least first integration recognition attB or attP site. [0064] In some embodiments of the method, the second integration recognition site is specific for BxB1 or a modified BxB1. [0065] In some embodiments of the method, the second integration recognition sites is comprised of 38 or 46 nucleotides. [0066] In some embodiments of the method, a second donor polynucleotide template is integrated into the pleiopluripotent cell genome at the second integration recognition site site-specifically incorporated into the pleiopluripotent cell genome. [0067] In some embodiments of the method, the second donor polynucleotide template encodes one or more therapeutic agents. [0068] In some embodiments of the method, the one or more therapeutic agents is selected from: transcription factors, receptors, signaling molecules, secreted proteins, cytokines, enzymes, or proteins promoting engraftment, trafficking, homing, viability, self-renewal, and persistence and/or survival of the iPSCs or cells derived from the iPSC. [0069] In some embodiments of the method, one or more therapeutic agents is a HLA class I protein. [0070] In some embodiments of the method, the one or more therapeutic agents is a HLA class II protein.
[0071] In some embodiments of the method, the second donor polynucleotide template comprises a pluripotent stem cell-specific promoter operably linked to at least one of the one or more therapeutic agents. [0072] In some embodiments of the method, the second donor polynucleotide template comprises a constitutive promoter operably linked to at least one of the one or more therapeutic agents. [0073] In some embodiments of the method, the second donor polynucleotide template comprises an inducible promoter operably linked to at least one of the one or more therapeutic agents. [0074] In some embodiments of the method, the first donor polynucleotide template integrated into the pleiopluripotent cell genome is at least 1 kilobase (kb), at least 2 kb, at least 3kb, at least4kb, at least 5kb, at least 6kb, at least 7kb, at least 8kb, at least 9kb, at least 10kb, at least 11kb, at least 12kb, at least 13kb, at least 14kb, at least 15kb, at least 16kb, at least 17kb, at least 18kb, at least 19kb, at least 20kb, at least 21kb, at least 22kb, at least 23kb, at least 24kb, at least 25kb, at least 26kb, at least 27kb, at least 28kb, at least 29kb, at least 30kb, at least 31kb, at least 32kb, at least 33kb, at least 34kb, or at least 35kb or more. [0075] In some embodiments of the method, the first donor polynucleotide template integrated into the pleiopluripotent cell genome is at least 30kb. [0076] In some embodiments of the method, the second donor polynucleotide template integrated into the pleiopluripotent cell genome is at least 1 kilobase (kb), at least 2kb, at least 3kb, at least 4kb, at least 5kb, at least 6kb, at least 7kb, at least 8kb, at least 9kb, at least 10kb, at least 11kb, at least 12kb, at least 13kb, at least 14kb, at least 15kb, at least 16kb, at least 17kb, at least 18kb, at least 19kb, at least 20kb, at least 21kb, at least 22kb, at least 23kb, at least 24kb, at least 25kb, at least 26kb, at least 27kb, at least 28kb, at least 29kb, at least 30kb, at least 31kb, at least 32kb, at least 33kb, at least 34kb, or at least 35kb or more. [0077] In some embodiments of the method, the second donor polynucleotide template integrated into the pleiopluripotent cell genome is at least 30kb. [0078] In some embodiments of the method, the pleiopluripotent cell is a pluripotent stem cell. [0079] In some embodiments of the method, the pluripotent stem cell is an embryonic stem cell or an induced pluripotent stem cell.
[0080] In some embodiments of the method, the pluripotent stem cell is an induced pluripotent stem cell. [0081] In some embodiments of the method, the induced pluripotent stem cell is a human induced pluripotent stem cell. [0082] In some embodiments, the method further comprises site-specifically excising from the genome of the pleiopluripotent cell the first donor polynucleotide template, the second donor polynucleotide template, or both. [0083] In some embodiments of the method, wherein the site-specifically excising is effected by introducing into the pleiopluripotent cell an integrase that recognizes the one or more orthogonal integration recognition sites in the first donor polynucleotide template, the second donor polynucleotide template, or both. [0084] In some embodiments, the method further comprises cryopreserving the pleiopluripotent cell or a population thereof. [0085] In another aspect, this disclosure features a pleiopluripotent cell or population thereof generated using the method any of the methods described herein. [0086] In another aspect, this disclosure features a second generation pleiopluripotent cell generated using the method of any of methods described herein. [0087] In another aspect, this disclosure features a third generation pleiopluripotent cell generated using the method of any of the methods described herein. [0088] In another aspect, this disclosure features a fourth generation pleiopluripotent cell generated using the method of any of the methods described herein. [0089] In another aspect, this disclosure features a pleiopluripotent cell, comprising: [0090] at least a first integration recognition site site-specifically incorporated into the pleiopluripotent cell genome. [0091] In another aspect, this disclosure features a pleiopluripotent cell comprising: [0092] a donor polynucleotide template comprised of one or more orthogonal integration recognition site integrated into the pleiopluripotent cell genome at an at least first integration
recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0093] In some embodiments of the pleiopluripotent cell, wherein at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a safe harbor locus. [0094] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition sites is site-specifically incorporated within a locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent cell or a cell matured from the pleiopluripotent cell. [0095] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition sites is site-specifically incorporated into the genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. In some embodiments, the pleiopluripotent cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. [0096] In some embodiments of the pleiopluripotent cell, the locus is in a chromosomal region selected from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. [0097] In some embodiments of the pleiopluripotent cell, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA- DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, and RFXANK locus. [0098] In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. [0099] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition sites is specific for a serine integrase. [0100] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition sites is an attB or attP site. [0101] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition sites is a modified attB or attP site.
[0102] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition sites is specific for BxB1 or a modified BxB1. [0103] In some embodiments of the pleiopluripotent cell, at least one of the at least first integration recognition site is comprised of 38 or 46 nucleotides. [0104] In some embodiments of the pleiopluripotent cell, the donor polynucleotide template encodes one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof. In some embodiments, inducing at least one of the one or more inducible suicide genes targets the pleiopluripotent cell or a cell matured from the pleiopluripotent cell for cell death. In some embodiments, expression of at least one of the one or more inducible suicide gene is driven by a pluripotent stem cell-specific promoter. In some embodiments, expression of at least one of the one or more inducible suicide gene is driven by a constitutive promoter. In some embodiments, expression of at least one of the one or more inducible suicide gene is driven by an inducible promoter. In some embodiments, the one or more inducible suicide genes is selected from: caspase9, cytosine deaminase, and thymidine kinase. In some embodiments, the one or more inducible suicide genes is a controllable caspase9. [0105] In some embodiments, AP20187 (or analog thereof) controls activity of Caspase9 or AP21967 (or analog thereof) controls activity of Caspase9. [0106] In some embodiments, the pleiopluripotent cell further comprises a second inducible suicide gene. In some embodiments, the second inducible suicide gene comprises a thymidine kinase. In some embodiments, the polynucleotide encoding for the thymidine kinase is operably linked to the controllable capase9 protein using a 2A self-cleaving peptide or an internal ribosome entry site. [0107] In some embodiments of the pleiopluripotent cell, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells. In some embodiments, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells by inhibiting, blocking, or preventing recognition of the PC-derived cell by macrophages, T-cells, Natural Killer (NK)-cells, antigen-presenting cells, or a combination thereof. [0108] In some embodiments of the pleiopluripotent cell, the one or more exogenous polypeptides capable of modulating an immune response are capable of serving as a safety switch target.
[0109] In some embodiments of the pleiopluripotent cell, expression of at least one of the one or more exogenous polypeptides capable of modulating an immune response is driven by a pluripotent stem cell-specific promoter. [0110] In some embodiments of the pleiopluripotent cell, expression of at least one of the one or more exogenous polypeptides capable of modulating an immune response is driven by a constitutive promoter. [0111] In some embodiments of the pleiopluripotent cell, expression of at least one of the one or more exogenous polypeptides capable of modulating an immune response is driven by an inducible promoter. [0112] In some embodiments of the pleiopluripotent cell, the one or more exogenous polypeptides capable of modulating an immune response is selected from: CD47, PDL-1, B2M-HLA-E, HLA- G, HACD16, 41BBL, CD3, CD4, CD8, CD137, CD80, and A2AR, or a combination thereof. In some embodiments, the donor polynucleotide template encodes a CD47, PDL1, and B2M-HLA- E. In some embodiments, the polynucleotide template encoding CD47, PDL1 and B2M-HLA-E are separated by a 2A self-cleaving peptide, an internal ribosome entry site, or a combination thereof. [0113] In some embodiments of the pleiopluripotent cell, the donor polynucleotide template further comprises a polynucleotide sequence encoding a tag. In some embodiments, the tag is an ALFA tag. [0114] In some embodiments, the pleiopluripotent cell comprises two integration recognition sites, three integration recognition sites, four integration recognition sites, five integration recognition sites, six integration recognition sites, seven integration recognition sites, eight integration recognition sites, nine integration recognition sites, or ten or more integration recognition sites. [0115] In some embodiments, the pleiopluripotent cell further comprises a second integration recognition site site-specifically incorporated into the pleiopluripotent cell genome. In some embodiments, the second integration recognition sites is site-specifically incorporated into a safe harbor locus. In some embodiments, the second integration recognition site is site-specifically incorporated within a second locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent cell or a cell matured from the pleiopluripotent cell. In some embodiments, the second integration recognition site is site-specifically incorporated into the
genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. In some embodiments, the pleiopluripotent cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. In some embodiments, the locus is in a chromosomal region selected from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. In some embodiments, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, and RFXANK locus. In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. [0116] In some embodiments of the pleiopluripotent cell, at least one of the at least second integration recognition sites is specific for a serine integrase. [0117] In some embodiments of the pleiopluripotent cell, the second integration recognition sites is different from the at least first integration recognition attB or attP site. [0118] In some embodiments of the pleiopluripotent cell, the second integration recognition sites is a modified attB or attP site. [0119] In some embodiments of the pleiopluripotent cell, the second integration recognition site is specific for BxB1 or a modified BxB1. [0120] In some embodiments of the pleiopluripotent cell, the second integration recognition sites is comprised of 38 or 46 nucleotides. [0121] In some embodiments of the pleiopluripotent cell, the second donor polynucleotide template encodes one or more therapeutic agents. In some embodiments, the one or more therapeutic agents is selected from: transcription factors, receptors, signaling molecules, secreted proteins, cytokines, enzymes, or proteins promoting engraftment, trafficking, homing, viability, self-renewal, and persistence and/or survival of the iPSCs or cells derived from the iPSC. In some embodiments, the one or more therapeutic agents is a HLA class I proteins. In some embodiments, the one or more therapeutic agents is a HLA class II proteins. In some embodiments, wherein the second donor polynucleotide template comprises a pluripotent stem cell-specific promoter operably linked to at least one of the one or more therapeutic agents.
[0122] In some embodiments of the pleiopluripotent cell, the second donor polynucleotide template comprises a constitutive promoter operably linked to at least one of the one or more therapeutic agent. [0123] In some embodiments of the pleiopluripotent cell, the second donor polynucleotide template comprises an inducible promoter operably linked to at least one of the one or more therapeutic agent. [0124] In some embodiments of the pleiopluripotent cell, the pleiopluripotent cell is a pluripotent stem cell. [0125] In some embodiments of the pleiopluripotent cell, the pluripotent stem cell is an embryonic stem cell or an induced pluripotent stem cell. [0126] In some embodiments of the pleiopluripotent cell, the pluripotent stem cell is an induced pluripotent stem cell. [0127] In some embodiments of the pleiopluripotent cell, the induced pluripotent stem cell is a human induced pluripotent stem cell. [0128] In another aspect, this disclosure features a composition comprising a clonal population of any of the pleiopluripotent cells described herein. [0129] In another aspect, this disclosure features a pharmaceutical composition comprising a clonal population of pleiopluripotent cells described herein and a pharmaceutically acceptable excipient or carrier. [0130] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site is incorporated site-specifically into the PC-derived cell genome. [0131] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome.
[0132] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a hematopoietic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site is incorporated site-specifically into the PC-derived cell genome. [0133] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a hematopoietic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0134] In some embodiments of the PC-derived cell or a population thereof, the hematopoietic cell is selected from: hematopoietic stem and progenitor cells (HSC), pre-HSC, hematopoietic multipotent progenitor (MPP) cells, pre-T cell progenitor cells, pre-NK cell progenitor cells, T cell progenitor cells, NK cell progenitor cells, T cells, NK cells, NKT cells, or B cells. [0135] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a neuronal cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site integration recognition sites incorporated site-specifically into the PSC-derived cell genome. [0136] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a neuronal cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0137] In some embodiments of the PC-derived cell or a population thereof, the neuronal cell is selected from: a neural progenitor cell (NPC), a forebrain neuron, a dopaminergic neuron, a motor neuron, and a sensory neuron. [0138] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a cardiac cell differentiated from a
pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site incorporated site-specifically into the PSC-derived cell genome. [0139] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a cardiac cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0140] In some embodiments of the PC-derived cell or a population thereof, the cardiac cell is selected from: a cardiac mesodermal cell, a cardiac progenitor cell, and a cardiomyocyte. [0141] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a pancreatic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site incorporated site-specifically into the PC-derived cell genome. [0142] In another aspect, this disclosure features a pleiopluripotent cell (PC)-derived cell or a population thereof, wherein (i) the PC-derived cell is a pancreatic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0143] In some embodiments of the PC-derived cell or a population thereof, the pancreatic cell is selected from a pancreatic progenitor cell, pancreatic endoderm, a endocrine pancreatic cell, an exocrine pancreatic cell, a islet progenitor, and a beta cell. [0144] In some embodiments of the PC-derived cell or a population thereof, the PC-derived cell further comprises two integration recognition sites, three integration recognition sites, four integration recognition sites, five integration recognition sites, six integration recognition sites, seven integration recognition sites, eight integration recognition sites, nine integration recognition sites, or ten or more integration recognition sites.
[0145] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a safe harbor locus. [0146] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition sites is site-specifically incorporated within a locus, disruption of which is capable of reducing allogeneic immune response to the PC-derived cell. [0147] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition sites is incorporated into the genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. [0148] In some embodiments of the PC-derived cell or a population thereof, the pleiopluripotent cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. [0149] In some embodiments of the PC-derived cell or a population thereof, the locus is in a chromosomal region selected from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. [0150] In some embodiments of the PC-derived cell or a population thereof, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA- DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. [0151] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first recognition sites is specific for a serine integrase. [0152] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition sites is an attB or attP site. [0153] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition sites is a modified attB or attP site. [0154] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition site is specific for BxB1 or a modified BxB1. [0155] In some embodiments of the PC-derived cell or a population thereof, at least one of the at least first integration recognition sites is comprised of 38 or 46 nucleotides.
[0156] In some embodiments of the PC-derived cell or a population thereof, the first donor polynucleotide template encodes one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof. In some embodiments, inducing at least one of the one or more inducible suicide genes targets the pleiopluripotent cell or a cell matured from the pleiopluripotent cell for cell death. In some embodiments, expression of at least one of the one or more inducible suicide gene is driven by a pluripotent stem cell-specific promoter. In some embodiments, expression of the at least one of the one or more inducible suicide genes is driven by a constitutive promoter. In some embodiments, expression of the at least one of the one or more inducible suicide genes is driven by an inducible promoter. In some embodiments, the one or more inducible suicide genes is select from: caspase9, cytosine deaminase, and thymidine kinase. In some embodiments, the one or more inducible suicide genes is a controllable caspase9. In some embodiments, AP20187 (or analog thereof) controls activity of Caspase9 or AP21967 (or analog thereof) controls activity of Caspase9. [0157] In some embodiments of the PC-derived cell or a population thereof, the cell further comprises a second inducible suicide gene. In some embodiments, the polynucleotide encoding for the second inducible suicide gene is operably linked to the controllable capase9 protein using a 2A self-cleaving peptide or an internal ribosome entry site. In some embodiments, the second inducible suicide gene comprises a thymidine kinase. [0158] In some embodiments of the PC-derived cell or a population thereof, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells. In some embodiments, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells by inhibiting, blocking, or preventing recognition of the PC-derived cell by macrophages, T- cells, Natural Killer (NK)-cells, antigen-presenting cells, or a combination thereof. In some embodiments, the one or more exogenous polypeptides capable of modulating an immune response are capable of serving as a safety switch target. [0159] In some embodiments of the PC-derived cell or a population thereof, expression of at least one of the one or more exogenous polypeptide capable of modulating an immune response is driven by a pluripotent stem cell-specific promoter.
[0160] In some embodiments of the PC-derived cell or a population thereof, expression of at least one of the one or more exogenous polypeptide capable of modulating an immune response is driven by a constitutive promoter. [0161] In some embodiments of the PC-derived cell or a population thereof, expression of at least one of the one or more exogenous polypeptide capable of modulating an immune response is driven by an inducible promoter. [0162] In some embodiments of the PC-derived cell or a population thereof, the one or more exogenous polypeptides capable of modulating an immune response is selected from: CD47, PDL- 1, B2M-HLA-E, HLA-G, HACD16, 41BBL, CD3, CD4, CD8, CD137, CD80, and A2AR, or a combination thereof. In some embodiments, the donor polynucleotide template encodes a CD47, PDL1, and B2M-HLA-E. In some embodiments, the polynucleotide template encoding CD47, PDL1 and B2M-HLA-E are separated by a 2A self-cleaving peptide, an internal ribosome entry site, or a combination thereof. [0163] In some embodiments of the PC-derived cell or a population thereof, the donor polynucleotide template further comprises a polynucleotide sequence encoding a tag. In some embodiments, the tag is an ALFA tag. [0164] In some embodiments of the PC-derived cell or a population thereof, the cell further comprises a second integration recognition site site-specifically incorporated into the pleiopluripotent cell genome. In some embodiments, the second integration recognition sites is site-specifically incorporated into a safe harbor locus. In some embodiments, the second integration recognition site is site-specifically incorporated within a second locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent cell or a cell matured from the pleiopluripotent cell. In some embodiments, the second integration recognition site is site-specifically incorporated into the genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. In some embodiments, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA- DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. [0165] In some embodiments of the PC-derived cell or a population thereof, the second integration recognition site is specific for a serine integrase.
[0166] In some embodiments of the PC-derived cell or a population thereof, the second integration recognition sites is different from the at least first integration recognition attB or attP site. [0167] In some embodiments of the PC-derived cell or a population thereof, the second integration recognition site is an attB or attP site. [0168] In some embodiments of the PC-derived cell or a population thereof, the second integration ecognition sites is a modified attB or attP site. [0169] In some embodiments of the PC-derived cell or a population thereof, the second integration ecognition site is specific for BxB1 or a modified BxB1. [0170] In some embodiments of the PC-derived cell or a population thereof, the second integration recognition sites is comprised of 38 or 46 nucleotides. [0171] In some embodiments of the PC-derived cell or a population thereof, the donor polynucleotide template encodes one or more orthogonal integration recognition sites. [0172] In some embodiments of the PC-derived cell or a population thereof, a second donor polynucleotide template is integrated into the PC-derived cell genome at the second integration recognition site site-specifically incorporated into the PC-derived cell genome. [0173] In some embodiments of the PC-derived cell or a population thereof, the first donor polynucleotide template is encodes one or more therapeutic agents. [0174] In some embodiments of the PC-derived cell or a population thereof, the one or more therapeutic agents is selected from: transcription factors, receptors, signaling molecules, secreted proteins, cytokines, enzymes, or proteins promoting engraftment, trafficking, homing, viability, self-renewal, and persistence and/or survival of the iPSCs or cells derived from the iPSC. [0175] In some embodiments of the PC-derived cell or a population thereof, the one or more therapeutic agents is a HLA class I proteins. [0176] In some embodiments of the PC-derived cell or a population thereof, the one or more therapeutic agents is a HLA class II proteins. [0177] In some embodiments of the PC-derived cell or a population thereof, the second donor polynucleotide template comprises a pluripotent stem cell-specific promoter operably linked to at least one of the one or more therapeutic agents.
[0178] In some embodiments of the PC-derived cell or a population thereof, the second donor polynucleotide template comprises a constitutive promoter operably linked to at least one of the one or more therapeutic agent. [0179] In some embodiments of the PC-derived cell or a population thereof, the second donor polynucleotide template comprises an inducible promoter operably linked to at least one therapeutic agent. [0180] In some embodiments of the PC-derived cell or a population thereof, the PC-derived cell or population thereof are human cells. [0181] In another aspect, this disclosure features a composition comprising any of the population of PC-derived cells described herein. [0182] In another aspect, this disclosure features a pharmaceutical composition comprising any of the population of PC-derived cells described herein and a pharmaceutically acceptable excipient or carrier. [0183] In another aspect, this disclosure features a method of treating or ameliorating or preventing a disease or condition in a subject, comprising administering a therapeutically effective amount of any of the PC-derived cells or populations described herein or any of the compositions described herein or any of the pharmaceutical composition described herein. [0184] In some embodiments of the method of treating or ameliorating or preventing a disease, the disease is a cancer. [0185] In some embodiments of the method of treating or ameliorating or preventing a disease, the disease is a muscular and/or the condition is muscle degeneration or muscle injury. [0186] In some embodiments of the method of treating or ameliorating or preventing a disease, the disease is a neuronal disease and/or the condition is neuron degeneration. [0187] In some embodiments of the method of treating or ameliorating or preventing a disease, the disease is associated with the pancreas. [0188] In another aspect, this disclosure features a method of using a pleiopluripotent cell having at least a first integration recognition site site-specifically incorporated into the pleiopluripotent cell genome, the method comprising: integrating a first donor polynucleotide template into the pleiopluripotent cell genome by introducing into the pleiopluripotent cell: (i) the donor
polynucleotide template, wherein the donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the at least one incorporated genomic integration recognition sites by the integrase. [0189] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises selecting the pleiopluripotent cells having the first donor polynucleotide template site- specifically integrated into the genome. [0190] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises expanding the pleiopluripotent cells in a de-differentiated state. [0191] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises cryopreserving the pleiopluripotent cells. [0192] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises directing differentiation of the modified pleiopluripotent cell to a hematopoietic cell. [0193] In some embodiments of the method of using the pleiopluripotent cell, the hematopoietic cell is selected from: hematopoietic stem and progenitor cells (HSC), pre-HSC, hematopoietic multipotent progenitor (MPP) cells, pre-T cell progenitor cells, pre-NK cell progenitor cells, T cell progenitor cells, NK cell progenitor cells, T cells, NK cells, NKT cells, or B cells. [0194] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises directing differentiation of the modified pleiopluripotent cell to a neuronal cell. [0195] In some embodiments of the method of using the pleiopluripotent cell, the neuronal cell is selected from: a neural progenitor cell (NPC), a forebrain neuron, a dopaminergic neuron, a motor neuron, and a sensory neuron. [0196] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises directing differentiation of the modified pleiopluripotent cell to a cardiac cell. [0197] In some embodiments of the method of using the pleiopluripotent cell, the cardiac cell is selected from: a cardiac mesodermal cell, a cardiac progenitor cell, and a cardiomyocyte. [0198] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises directing differentiation of the modified pleiopluripotent cell to a pancreatic cell.
[0199] In some embodiments of the method of using the pleiopluripotent cell, the cardiac cell is selected from: pancreatic progenitor cell, pancreatic endoderm, an endocrine pancreatic cell, an exocrine pancreatic cell, an islet progenitor, and a beta cell. [0200] In some embodiments of the method of using the pleiopluripotent cell, the method further comprises administering the PC-derived cells or a population thereof to a patient in need thereof. 5. BRIEF DESCRIPTION OF THE DRAWINGS [0201] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, and accompanying drawings, where: [0202] FIG.1A-1E shows analysis of AttP variants. FIG.1A shows a non-limiting schematic of AttP mutations tested for improving integration efficiency (SEQ ID NOS: 394 and 540-542, respectively, in order of appearance). FIG. 1B shows integration efficiencies of wildtype and mutant AttP sites across a panel of AttB lengths. FIG. 1C shows a non-limiting schematic of multiplexed integration of different cargo sets at specific genomic loci. Three fluorescent cargos (GFP, mCherry, and YFP) are inserted orthogonally at three different loci (ACTB, LMNB1, NOLC1) for in-frame gene tagging. FIG.1D shows orthogonality of top 4 AttB/AttP dinucleotide pairs evaluated for GFP integration with PASTE at the ACTB locus. FIG.1E shows efficiency of multiplexed PASTE insertion of combinations of fluorophores at ACTB, LMNB1, and NOLC1 loci. Data are mean (n= 3) ± s.e.m. [0203] FIG.2 illustrates a schematic of a non-limiting example of engineered pleiopluripotent cell having a knockout of HLA Class I and/or II, one or more exogenous polypeptides capable of modulating an immune response, one or more inducible suicide genes, one or more adaptors, and optionally one or more beacons for inserting additional therapeutic genes. [0204] FIG. 3A illustrates a schematic of a donor polynucleotide template: NANOG- FKBPCasp9-ACTB-mFRBFKBPCasp9-CAG-CD47-PDL1-HLAE-3AttB and integration of the donor polynucleotide into exon 1 of the B2M locus. Abbreviations (top panel): B2M – beta-2 microglobulin. Nanog – endogenous promoter that drives expression of Nanog. FKBPCasp9: FK506-binding protein fused to caspase 9. ACTB-mFRB-FKBP-Casp9: Actin promoter driving expression of an FRB domain and FKBP-Casp9. ALFA – epitope tag. CD47: Cluster of Differentiation 47 (i.e., an example exogenous polypeptide capable of modulating an immune response). PD-L1: Programmed death-ligand 1. B2M: Beta-2-Microglobulin. HLA-E: Major
Histocompatibility Complex, Class I, E. AttB1 (AA): AttB1 site with a AA dinucleotide. AttB2 (CG): AttB site with a CG dinucleotide. AttB3 (CC): AttB site with a CC dinucleotide. [0205] FIG. 3B illustrates a schematic of a donor polynucleotide template: PTRE3G-B2M- pA-hPGKprm-Tet3G-pA and integration of the donor polynucleotide template into exon 2 of the CIITA locus. Abbreviations (bottom panel): PTRE3G – TetO promoter. B2M - beta-2 microglobulin. pA – SV40 poly A tail. hPGK prm – human phosphoglycerate kinase gene promoter. Tet3G – tet transactivator. [0206] FIG.4 illustrates a schematic of an example inducible suicide gene. Left panel shows non-limiting examples Caspase9-based suicide genes. Right panel shows non-limiting examples of exogenous molecules that control activity of Caspase 9. [0207] FIG. 5 illustrates a schematic of single atgRNA and dual atgRNA approaches for beacon placement. [0208] FIG.6 shows the source of protospacer sequences for each atgRNA targeting human B2M and human CIITA genes and the dual atgRNA approach for targeting the B2M and CIITA loci. [0209] FIGs. 7A-7B illustrates designing of atgRNAs capable of beacon placement into a target genome site. Exemplary 38 or 46 base attB insertion sites are shown. FIG.7A shows a non- limiting example workflow for designing single atgRNA and dual atgRNA approaches for beacon placement. FIG.7B shows a non-limiting example workflow for designing each atgRNA. [0210] FIG.8 illustrates a non-limiting example workflow for editing pleiopluripotent cells. [0211] FIG.9 illustrates the modified atgRNA sequences for targeting the B2M and CIITA loci. Non-modified RNA are entered as ‘r_’. For example, as rA or rU.2’ O-methyl RNA are entered as ‘m_’. Phosphorothioated RNA are entered as ‘r_*’. Phosphorothioated 2’ O-methyl RNA are entered as ‘m_*’. [0212] FIGs. 10A-10B illustrate beacon placement in two different iPSC lines (iPSC line 1 was in FIG. 10A and iPSC line 2 was in FIG. 10B) across tested conditions for two different genomic loci in each iPSC line (B2M and CIITA loci). Beacon placement was determined by ddPCR and amp-seq.
[0213] FIGs.11A-11B illustrate concurrent beacon placement at B2M and CIITA loci using a dual atgRNA approach for beacon placement at each loci. Beacon placement was determined by ddPCR. FIG.11A shows raw data from ddPCR. FIG.11B shows a histogram summarizing data from FIG.11A. [0214] FIGs. 12A-12B illustrate beacon placement data for various iPSC lines. FIG. 12A shows raw ddPCR data for beacon placement at the B2M loci and the CIITA loci for 22 iPSC lines. FIG.12B shows a histogram summarizing ddPCR data for three iPSC lines. Lines 1 and 9 show 100% (i.e., bi-allelic) beacon placement at both B2M and CIITA loci. [0215] FIG.13 shows Amp-seq data for beacon placement in six iPSC cell lines generated in Example 2. [0216] FIGs.14A-14B illustrate a schematic of the digital droplet PCR (ddPCR) assay used to detect integration of a donor polynucleotide at the B2M locus (FIG. 14A) or the CIITA locus (FIG.14B). Similar designs can be used to determine integration at other genomic loci. [0217] FIG. 15 shows data for integration of a 6 kilobase (kb) first donor polynucleotide template into the B2M locus (site 1) and a 5kb second donor polynucleotide template into the CIITA locus (site 2). Data is presented as transductions that include a single donor polynucleotide template, thereby measuring a single integration of donor polynucleotide template at either the B2M locus or the CIITA locus (single integration), referred to in FIG.15 as “single.” Data is also presented for transductions that include both the first and second donor polynucleotide templates, thereby showing concurrent integration of the donor polynucleotide templates at the B2M locus and CIITA locus, referred to in FIG.15 as “Duplex”. [0218] FIG.16 shows data for programmable gene insertion (i.e., integration) of a 31 kb donor polynucleotide template at the CIITA locus that has an integration recognition site site-specifically incorporated into exon 2. The 31 kb donor polynucleotide (Adv donor) was delivered to the induced pluripotent stem cell (iPSC) using adenovirus at MOIs of 0.01, 0.1, 1, and 10. [0219] FIG.17 shows polynucleotide and amino acid sequences for the donor polynucleotide template described in FIG.3A. FIG.17 includes the polynucleotide sequence (SEQ ID NO: 616) of the donor polynucleotide template that is integrated into the B2M locus. FIG.17 also includes the FKBP-linker-Caspase9 amino acid sequence (SEQ ID NO: 662); the mFRB-linker-FKBP- Caspase9-P2A-DeltaTK amino acid sequence (SEQ ID NO: 663); and the alpha tag-CD47-P2A- PDL1-T2A-B2M-HLA-E amino acid sequence (SEQ ID NO: 664).
[0220] FIG. 18 shows polynucleotide and amino acid sequences for donor polynucleotide template described in FIG.3B. FIG.18 includes the polynucleotide sequence (SEQ ID NO: 617) of the donor polynucleotide template that is integrated into the CIITA locus. FIG.18 also includes the B2M amino acid sequence (SEQ ID NO: 665) and the Tet3G amino acid sequence (SEQ ID NO: 666). [0221] FIG.19A shows ddPCR data for percent beacon placement in the CD52 locus in iPSC clone #17 following electroporation with the atgRNA pairs indicated on the x-axis and identified in the key. [0222] FIG.19B shows next-generation sequencing data for percent beacon placement in the CD52 locus in iPSC clone #17 following electroporation with the atgRNA pairs indicated on the x-axis that include a subset of the atgRNAs identified in the key in FIG.19A. [0223] FIG.20A shows ddPCR data for percent beacon placement in the CISH locus in iPSC clone #17 following electroporation with the atgRNA pairs indicated on the x-axis, which are also described in Example 6. [0224] FIG.20B shows next-generation sequencing data for percent beacon placement in the CISH locus in iPSC clone #17 following electroporation with the atgRNA pairs indicated on the x-axis. The pairs in FIG.20B correspond to the pairs in FIG.20A as follows: pair 1 corresponds to SP01-N01, pair 2 corresponds to SP02-N02, pair 5 corresponds to SP05-N04, pair 3 corresponds to SP03-N03, and pair 4 corresponds to SP04-N04. [0225] FIG. 21A shows ddPCR data for percent beacon placement in the ADRA2A locus in iPSC clone #17 following electroporation with the atgRNA pairs indicated on the x-axis, which are also described in Example 7. [0226] FIG.21B shows next-generation sequencing data for percent beacon placement in the ADRA2A locus in iPSC clone #17 following electroporation with the atgRNA pairs indicated on the x-axis. The pairs in FIG. 21B correspond to the pairs in FIG. 21A as follows: pair 1 corresponds to SP01-N01, pair 2 corresponds to SP02-N02, pair 3 corresponds to SP03-N03, pair 4 corresponds to SP04-N04, and pair 5 corresponds to SP05-N05. [0227] FIG. 22 shows ddPCR data for percent beacon placement in the B2M, CIITA, and CD52 loci in a wild type iPSC line following electroporation with the indicated combinations of atgRNA pairs. Abbreviations: “3X” indicates electroporation with three atgRNA pairs for
multiplex beacon placement; bmp001, bmp002, bmp003, and mod2 indicate the atgRNA is modified. [0228] FIG.23 shows ddPCR data for percent beacon placement in the TRAC and AAVS1 loci in iPSC clone # 17 following electroporation with the atgRNA pairs indicated on the x-axis. Data is shown for negative control, electroporation of TRAC atgRNA pair only, electroporation of AAVS1 atgRNA pair only, and the co-electroporation of the TRAC and AAVS1 atgRNA pairs. DKO #17 indicates that iPSC clone includes beacons site-specifically incorporated into B2M and CIITA loci prior to being electroporated with the TRAC and AAVS1 atgRNAs. [0229] FIG.24 shows a non-limiting example of the clonal isolation process for generating an iPSC clone. The overall process takes roughly a month from electroporation to NGS analysis. First, electroporation (EP) is used to place beacons in the iPS cells. Electroporated iPSCs are grown for 72 hours and part of the iPSC culture is harvested for genomic DNA to get an initial read of beacon placement. If cells are positive for beacon placement, electroporation is scaled up from a 48 well plate to a 24 well plate and then eventually to 6 wells. A confluent 6 well population of cells is diluted such that a single cell is placed in each well of a 96-well plate across multiple 96 well plates. These cells take roughly two weeks to reach the point of needing to be harvested. Cell growth is monitored and only clones with good morphology and growth rates are expanded and/or harvested for a second round of ddPCR. Cells with high performing beacon placement (e.g., beacon placement at both the TRAC and AAVS1 loci) are scaled up a final time to 6 well plates. The last step being to send samples for NGS analysis and cryopreserve the remaining cells. [0230] FIG.25 shows next generation sequencing data from iPSC clones generated using the method described in FIG.24. Abbreviations: Total # = total number of reads; and merge R1/R2 = merged reads 1 and 2. [0231] FIG. 26 shows ddPCR data for programmable gene insertion of four different donor polynucleotide templates at the B2M, CIITA, TRAC, and AAVS1 loci in iPSC clones #16 and #29. Each donor polynucleotide template includes an AttP site having a different central dinucleotide that enables integration at its corresponding (cognate) AttB site that has been site-specifically integrated into the iPS cell genome at one of the indicated loci. Controls include no BxB1 control (i.e., donor polynucleotide templates but no BxB1) and a no donor polynucleotide template control (i.e., a BxB1 polypeptide or polynucleotide encoding a BxB1 polypeptide but no donor polynucleotide templates.
[0232] FIG. 27 shows ddPCR data for programmable gene insertion of four different donor polynucleotide templates at the B2M, CIITA, TRAC, and AAVS1 loci in iPSC clones #30. Each donor polynucleotide template includes an AttP site having a different central dinucleotide that enables integration at its corresponding (cognate) AttB site that has been site-specifically integrated into the iPS cell genome at one of the indicated loci. 6. DETAILED DESCRIPTION OF THE INVENTION [0233] In one aspect, the methods described herein enable multiplexed programmable gene insertion whereby multiple edits (e.g., beacon placement, donor polynucleotide incorporation, or a combination thereof) can be performed sequentially or simultaneously in a single pleiopluripotent cell, thereby reducing the time and cost associated with conventional methods of editing pleiopluripotent cells. Additionally, the methods described herein avoid the need for inducing double strand breaks, which increases accuracy of genome integration and reduces likelihood of off-target events. For example, using a beacon (e.g., an integration recognition site) incorporated at a particular genomic location to guide integration of the donor polynucleotide template increases integration efficiency of the donor polynucleotide template. Moreover, the methods described herein enable integration of larger donor polynucleotide template sequences compared to conventional methods which have payload capacity limitations. This is enabled, at least in part, by using single atgRNA (and optionally a nicking gRNA) or dual atgRNA to guide precise beacon placement (i.e., incorporation of one or more integration recognition sites) at desired loci. One application of these methods is the generation of pleiopluripotent cells that include one or more of (i) knockout of HLA Class I and/or Class II molecules, (ii) expression of self-molecules (e.g., one or more exogenous polypeptides capable of modulating an immune response), (iii) expression one or more controllable (e.g., inducible) suicide genes, (iv) expression of one or more adaptors (e.g., a tag), and (v) one or more landing pads (e.g., beacons) incorporated into the genome for integrating additional therapeutic agents (see FIG.2). Cells comprising one or more of these features provide a source of cells suitable for differentiation to a cell type of interest (e.g., without limitation, a hematopoietic cell, a neuronal cell, a cardiac cell, and a pancreatic cell) and use in cell therapy (e.g., allogeneic cell therapy). 6.1. Terminology [0234] Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this disclosure belongs. As used herein, the following terms have the meanings ascribed to them below.
[0235] “Gene editor” as used herein, is a protein that that can be used to perform gene editing, gene modification, gene insertion, gene deletion, or gene inversion. As used herein, the terms “gene editor polynucleotide” refers to a polynucleotide sequence encoding the gene editor polypeptide. Such an enzyme or enzyme fusion may contain DNA or RNA targetable nuclease protein (i.e., Cas protein, ADAR, or ADAT), wherein target specificity is mediated by a complexed nucleic acid (i.e., guide RNA). Such an enzyme or enzyme fusion may be a DNA/RNA targetable protein, wherein target specificity is mediated by internal, conjugated, fused, or linked amino acids, such as within TALENs, ZFNs, or meganucleases. The skilled person in the art would appreciate that the gene editor can demonstrate targeted nuclease activity, targeted binding with no nuclease activity, or targeted nickase activity (or cleavase activity). A gene editor comprising a targetable protein may be fused or linked to one or more proteins or protein fragment motifs. Gene editors may be fused, linked, complexed, operate in cis or trans to one or more integrase, recombinase, polymerase, telomerase, reverse transcriptase, or invertase. A gene editor can be a prime editor fusion protein or a gene writer fusion protein. [0236] “Prime editor fusion protein” as used herein, describes a protein that is used in prime editing. “Prime editor system” as used herein describes the components used in prime editing. Prime editing uses CRISPR enzyme that nicks or cuts only single strand of double stranded DNA, i.e., a nickase; the nickase can occur either naturally or by mutation or modification of a nuclease that makes double stranded cuts. Such an enzyme can be a catalytically impaired Cas9 endonuclease (a nickase). Such an enzyme can be a Casl2a/b, MAD7, or variant thereof. The nickase is fused to an engineered reverse transcriptase (RT). The nickase is programmed (directed) with an attachment site-containing guide RNA (or a prime-editing guide RNA (pegRNA)). The skilled person in the art would appreciate that the pegRNA both specifies the target site and encodes the desired edit. Described herein, are attachment site-containing guide RNA (atgRNA) that both specifies the target and encodes for the desired integrase target recognition site. The nickase may be programmed (directed) with an atgRNA. Advantageously the nickase is a catalytically-impaired Cas9 endonuclease, a Cas9 nickase, that is fused to the reverse transcriptase. During genetic editing, the Cas9 nickase part of the protein is guided to the DNA target site by the atgRNA (or pegRNA), whereby a nick or single stranded cut occurs. The reverse transcriptase domain then uses the atgRNA (or pegRNA) to template reverse transcription of the desired edit, directly polymerizing DNA onto the nicked target DNA strand. The edited DNA strand replaces the original DNA strand, creating a heteroduplex containing one edited strand and one unedited strand. Afterward, optionally, the prime editor (PE) guides resolution of the heteroduplex to favor copying the edit onto the unedited strand, completing the process (typically achieved with a
nickase gRNA). Other enzymes that can be used to nick or cut only a single strand of double stranded DNA includes a cleavase (e.g., cleavase I enzyme). [0237] In some embodiments, an additional agent or agents may be added that improve the efficiency and outcome purity of the prime edit. In some embodiments, the agent may be chemical or biological and disrupt DNA mismatch repair (MMR) processes at or near the edit site (i.e., PE4 and PE5 and PEmax architecture by Chen et al. Cell, 184, 1-18, October 28, 2021; Chen et al. is incorporated herein by reference). In typical embodiments, the agent is a MMR-inhibiting protein. In certain embodiments, the MMR-inhibiting protein is dominant negative MMR protein. In certain embodiments, the dominant negative MMR protein is MLH1dn. In particular embodiments, the MMR-inhibiting agent is incorporated into the single nucleic acid construct design described herein. In some embodiments, the MMR-inhibiting agent is linked or fused to the prime editor protein fusion, which may or may not have a linked or fused integrase. In some embodiments, the MMR-inhibiting agent is linked or fused to the Gene Writer™ protein, which may or may not have a linked or fused integrase. [0238] The prime editor or gene editor system can be used to achieve DNA deletion and replacement. In some embodiments, the DNA deletion replacement is induced using a pair of atgRNAs (or pegRNA) that target opposite DNA strands, programming not only the sites that are nicked but also the outcome of the repair (i.e., PrimeDel by Choi et al. Nat. Biotechnology, October 14, 2021; Choi et al. is incorporated herein by reference and TwinPE by Anzalone et al., Nat. Biotech. 40: 731–740 (2022); Anzalone et al. is incorporated herein by reference). In some embodiments described herein, the DNA deletion is induced using a single atgRNA. In some embodiments, the DNA deletion and replacement is induced using a wild type Cas9 prime editor (PE-Cas9) system (i.e., PEDAR by Jiang et al. Nat. Biotechnology, October 14, 2021; Jiang et al. is incorporated herein by reference). In some embodiments, the DNA replacement is an integrase target recognition site or recombinase target recognition site. In certain embodiments, the constructs and methods described herein may be utilized to incorporate the pair of pegRNAs used in PrimeDel, TwinPE (WO2021226558, which is hereby incorporated by reference herein in its entirety), or PEDAR, the prime editor fusion protein or Gene Writer protein, optionally a nickase guide RNA (ngRNA), an integrase, a nucleic acid cargo, and optionally a recombinase into a single nucleic acid construct described herein. The integrase may be directly linked, for example by a peptide linker, to the prime editor fusion or gene writer protein. [0239] In some embodiments, the prime editors can refer to a retrovirus or lentivirus reverse transcriptase such as a Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase (RT)
fused to a CRISPR enzyme nickase such as a Cas9 H840A nickase, a Cas9nickase. In some embodiments, the prime editors can refer to a retrovirus or lentivirus reverse transcriptase such as a Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase (RT) fused to a cleavase. In some embodiments the RT can be fused at, near or to the C-terminus of a Cas9nickase, e.g., Cas9 H840A. Fusing the RT to the C-terminus region, e.g., to the C-terminus, of the Cas9 nickase may result in higher editing efficiency. Such a complex is called PEI. In some embodiments, the CRISPR enzyme nickase, e.g., Cas9(H840A), i.e., a Cas9nickase, can be linked to a non-M-MLV reverse transcriptase such as an AMV-RT or XRT (Cas9(H840A)-AMV-RT or XRT). In some embodiments, instead of the CRISPR enzyme nickase being a Cas9 (H840A), i.e., instead of being a Cas9 nickase, the CRISPR enzyme nickase instead can be a CRISPR enzyme that naturally is a nickase or cuts a single strand of double stranded DNA; for instance, the CRISPR enzyme nickase can be Casl2a/b. Alternatively, the CRISPR enzyme nickase can be another mutation of Cas9, such as Cas9(Dl0A). A CRISPR enzyme, such as a CRISPR enzyme nickase, such as Cas9 (wild type), Cas9(H840A), Cas9(Dl0A) or Cas 12a/b nickase can be fused in some embodiments to a pentamutant of M-MLV RT (D200N/ L603W/ T330P/ T306K/ W313F), whereby there can be up to about 45-fold higher efficiency, and this is called PE2. In some embodiments, the M-MLV RT comprise one or more of the mutations Y8H, P51L, S56A, S67R, E69K, Vl29P, L139P, Tl97A, H204R, V223H, T246E, N249D, E286R, Q2911, E302K, E302R, F309N, M320L, P330E, L435G, L435R, N454K, D524A, D524G, D524N, E562Q, D583N, H594Q, E607K, D653N, and L671P. Specific M-MLV RT mutations are shown in Table 1.

[0240] In some embodiments, the reverse transcriptase can also be a wild-type or modified transcription xenopolymerase (RTX), avian myeloblastosis virus reverse transcriptase (AMV RT), Feline Immunodeficiency Virus reverse transcriptase (FIV-RT), FeLV-RT (Feline leukemia virus reverse transcriptase), HIV-RT (Human Immunodeficiency Virus reverse transcriptase). In some embodiments, the reverse transcriptase can be a fusion of MMuLV to the Sto7d DNA binding
domain (see Ionnidi et al.; https://doi.org/10.1101/2021.11.01.466786). The fusion of MMuLV to the Sto7d DNA binding domain sequence is given in Table 2.

[0241] PE3, PE3b, PE4, PE5, and/or PEmax, which a skilled person can incorporate into the gene editor polypeptide, involves nicking the non-edited strand, potentially causing the cell to remake that strand using the edited strand as the template to induce HR. The nicking of the non-edited strand can involve the use of a nicking guide RNA (ngRNA). [0242] The skilled person can readily incorporate into a gene editor polypeptide described herein a prime editing or CRISPR system. Examples of prime editors can be found in the following: WO2020/191153, WO2020/191171, WO2020/191233, WO2020/191234, WO2020/191239, WO2020/191241, WO2020/191242, WO2020/191243, WO2020/191245, WO2020/191246, WO2020/191248, WO2020/191249, each of which is incorporated by reference herein in its entirety. In addition, mention is made, and can be used herein, of CRISPR Patent Applications and Patents of the Zhang laboratory and/or Broad Institute, Inc. and Massachusetts Institute of Technology and/or Broad Institute, Inc., Massachusetts Institute of Technology and President and Fellows of Harvard College and/or Editas Medicine, Inc. Broad Institute, Inc., The University of Iowa Research Foundation and Massachusetts Institute of Technology, including those claiming priority to US Application 61/736,527, filed December 12, 2012, including US Patents 11,104,937, 11,091,798, 11,060,115, 11,041,173, 11,021,740, 11,008,588, 11,001,829, 10,968,257, 10,954,514, 10,946,108, 10,930,367, 10,876,100, 10,851,357, 10,781,444, 10,711,285, 10,689,691, 10,648,020, 10,640,788, 10,577,630, 10,550,372, 10,494,621, 10,377,998, 10,266,887, 10,266,886, 10,190,137, 9,840,713, 9,822,372, 9,790,490, 8,999,641, 8,993,233, 8,945,839, 8,932,814, 8,906,616, 8,895,308, 8,889,418, 8,889,356, 8,871,445, 8,865,406, 8,795,965, 8,771,945, and 8,697,359; CRISPR Patent Applications and Patents of the Doudna laboratory and/or of Regents of the University of California, the University of Vienna and Emmanuelle
Charpentier, including those claiming priority to US application 61/652,086, filed May 25, 2012, and/or 61/716,256, filed October 19, 2012, and/or 61/757,640, filed January 28, 2013, and/or 61/765,576, filed February 15, 2013 and/or 13/842,859, including US Patents 11,028,412, 11,008,590, 11,008,589, 11,001,863, 10,988,782, 10,988,780, 10,982,231, 10,982,230, 10,900,054, 10,793,878, 10,774,344, 10,752,920, 10,676,759, 10,669,560, 10,640,791, 10,626,419, 10,612,045, 10,597,680, 10,577,631, 10,570,419, 10,563,227, 10,550,407, 10,533,190, 10,526,619, 10,519,467, 10,513,712, 10,487,341, 10,443,076, 10,428,352, 10,421,980, 10,415,061, 10,407,697, 10,400,253, 10,385,360, 10,358,659, 10,358,658, 10,351,878, 10,337,029, 10,308,961, 10,301,651, 10,266,850, 10,227,611, 10,113,167, and 10,000,772; CRISPR Patent Applications and Patents of Vilnius University and/or the Siksnys laboratory, including those claiming priority to US application 62/046384 and/or 61/625,420 and/or 61/613,373 and/or PCT/IB2015/056756, including US Patent 10,385,336; CRISPR Patent Applications and Patents of the President and Fellows of Harvard College, including those of George Church’s laboratory and/or claiming priority to US application 61/738,355, filed December 17, 2012, including 11,111,521, 11,085,072, 11,064,684, 10,959,413, 10,925,263, 10,851,369, 10,787,684, 10,767,194, 10,717,990, 10,683,490, 10,640,789, 10,563,225, 10,435,708, 10,435,679, 10,375,938, 10,329,587, 10,273,501, 10,100,291, 9,970,024, 9,914,939, 9,777,262, 9,587,252, 9,267,135, 9,260,723, 9,074,199, 9,023,649; CRISPR Patent Applications and Patents of the President and Fellows of Harvard College, including those of David Liu’s laboratory, including 11,111,472, 11,104,967, 11,078,469, 11,071,790, 11,053,481, 11,046,948, 10,954,548, 10,947,530, 10,912,833, 10,858,639, 10,745,677, 10,704,062, 10,682,410, 10,612,011, 10,597,679, 10,508,298, 10,465,176, 10,323,236, 10,227,581, 10,167,457, 10,113,163, 10,077,453, 9,999,671, 9,840,699, 9,737,604, 9,526,784, 9,388,430, 9,359,599, 9,340,800, 9,340,799, 9,322,037, 9,322,006, 9,228,207, 9,163,284, and 9,068,179; and CRISPR Patent Applications and Patents of Toolgen Incorporated and/or the Kim laboratory and/or claiming priority to US application 61/717,324, filed October 23, 2012 and/or 61/803,599, filed March 20, 2013 and/or 61/837,481, filed June 20, 2013 and/or 62/033,852, filed August 6, 2014 and/or PCT/KR2013/009488 and/or PCT/KR2015/008269, including US Patent 10,851,380, and 10,519,454; and CRISPR Patent Applications and Patents of Sigma and/or Millipore and/or the Chen laboratory and/or claiming priority to US application 61/734,256, filed December 6, 2012 and/or 61/758,624, filed January 30, 2013 and/or 61/761,046, filed February 5, 2013 and/or 61/794,422, filed March 15, 2013, including US Patent 10,731,181, each of which is hereby incorporated herein by reference, and from the disclosures of the foregoing, the skilled
person can readily make and use a prime editing or CRISPR system, and can especially appreciate impaired endonucleases, such as a mutated Cas9 that only nicks a single strand of DNA and is hence a nickase, or a CRISPR enzyme that only makes a single-stranded cut that can be employed in a PASTE system of the invention. Further, from the disclosures of the foregoing, the skilled person can incorporate the selected CRISPR enzyme, as part of the gene editor composition described herein. Additional gene editor polypeptides are as described in WO 2023/076898; WO 2023/015014; WO 2023/070062; WO2023288332; WO2023015318; WO2023004439; WO2023070110; WO2022256714; and WO2023283092, each of which are hereby incorporated by reference in their entireties. Additional gene editor polypeptides are as described in U.S. Patent Pub.2023/0059368, which is hereby incorporated by reference in its entirety. [0243] Prior to RT-mediated edit incorporation, the prime editor protein (1) site- specifically targets a genomic locus and (2) performs a catalytic cut or nick. These steps are typically performed by a CRISPR-Cas. However, in some embodiments the Cas protein may be substituted by other nucleic acid programmable DNA binding proteins (napDNAbp) such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), or meganucleases. In addition, to the extent the “targeting rules” of other napDNAbp are known or are newly determined, it becomes possible to use new napDNAbp, beyond Cas9, to site specifically target and modify genomic sites of interest. [0244] Similar to a prime editor protein, a Gene Writer can introduce novel DNA elements, such as an integration target site, into a DNA locus. A Gene Writer protein comprises: (A) a polypeptide or a nucleic acid encoding a polypeptide, wherein the polypeptide comprises (i) a reverse transcriptase domain, and either (x) an endonuclease domain that contains DNA binding functionality or (y) an endonuclease domain and separate DNA binding domain; and (B) a template RNA comprising (i) a sequence that binds the polypeptide and (ii) a heterologous insert sequence. Examples of such Gene Writer™ proteins and related systems can be found in US20200109398, which is incorporated by reference herein in its entirety. [0245] In some embodiments, the prime editor or Gene Writer protein fusion or prime editor protein linked or fused to an integrase is expressed as a split construct. In typical embodiments, the split construct in reconstituted in a cell. In some embodiments, the split construct can be fused or ligated via intein protein splicing. In some embodiments, the split construct can be reconstituted via protein-protein inter-molecular bonding and/or interactions. In some embodiments, the split construct can be reconstituted via chemical, biological, or environmental induced oligomerization.
In some embodiments, the split construct can be reconstituted via nanobody binding ALFA-tagged proteins. In certain embodiments, the split construct can be adapted into one or more single nucleic acid polynucleotides. [0246] In some embodiments, an integrase or recombinase is directly linked or fused, for example by a peptide linker, which may be cleavable or non-cleavable, to the prime editor fusion protein (i.e., fused Cas9 nickase-reverse transcriptase) or Gene Writer protein. Suitable linkers, for example between the Cas9, RT, and integrase, may be selected from Table 3:

Table 3

6.2. Type II CRISPR proteins [0247] The skilled person can incorporate a selected CRISPR enzyme, described below, as part of the prime editor fusion, as a component of the gene editor polypeptide described herein. Streptococcus pyogenes Cas9 (SpCas9), the most common enzyme used in genome-editing applications, is a large nuclease of 1368 amino acid residues. Advantages of SpCas9 include its
short, 5′-NGG-3′ PAM and very high average editing efficiency. SpCas9 consists of two lobes: a recognition (REC) lobe and a nuclease (NUC) lobe. The REC lobe can be divided into three regions, a long a helix referred to as the bridge helix (residues 60–93), the REC1 (residues 94–179 and 308–713) domain, and the REC2 (residues 180–307) domain. The NUC lobe consists of the RuvC (residues 1–59, 718–769, and 909–1098), HNH (residues 775–908), and PAM-interacting (PI) (residues 1099–1368) domains. The negatively charged sgRNA:target DNA heteroduplex is accommodated in a positively charged groove at the interface between the REC and NUC lobes. In the NUC lobe, the RuvC domain is assembled from the three split RuvC motifs (RuvC I–III) and interfaces with the PI domain to form a positively charged surface that interacts with the 30 tail of the sgRNA. The HNH domain lies between the RuvC II–III motifs and forms only a few contacts with the rest of the protein. Structural aspects of SpCas9 are described by Nishimasu et al., Crystal Structure of Cas9 in Complex with Guide RNA and Target DNA, Cell 156, 935-949, February 27, 2014. [0248] REC lobe: The REC lobe includes the REC1 and REC2 domains. The REC2 domain does not contact the bound guide:target heteroduplex, indicating that truncation of REC lobe may be tolerated by SpCas9. Further, SpCas9 mutant lacking the REC2 domain (D175–307) retained ~50% of the wild-type Cas9 activity, indicating that the REC2 domain is not critical for DNA cleavage. In striking contrast, the deletion of either the repeat-interacting region (D97–150) or the anti-repeat-interacting region (D312–409) of the REC1 domain abolished the DNA cleavage activity, indicating that the recognition of the repeat:anti-repeat duplex by the REC1 domain is critical for the Cas9 function. [0249] PAM-Interacting domain: The NUC lobe contains the PAM-interacting (PI) domain that is positioned to recognize the PAM sequence on the noncomplementary DNA strand. The PI domain of SpCas9 is required for the recognition of 5’-NGG-3’ PAM, and deletion of the PI domain (Δ1099-1368) abolished the cleavage activity, indicating that the PI domain is critical for SpCas9 function and a major determinant for the PAM specificity. [0250] RuvC domain: The RuvC nucleases of SpCas9 have an RNase H fold and four catalytic residues, Asp10 (Ala), Glu762, His983, and Asp986, that are critical for the two-metal cleavage of the noncomplementary strand of the target DNA. In addition to the conserved RNase H fold, the Cas9 RuvC domain has other structural elements involved in interactions with the guide:target heteroduplex (an end-capping loop between α42 and α43) and the PI domain/stem loop 3 (β hairpin formed by β3 and β4).
[0251] HNH domain: SpCas9 HNH nucleases have three catalytic residues, Asp839, His840, and Asn863 and cleave the complementary strand of the target DNA through a single-metal mechanism. [0252] sgRNA:DNA recognition: The sgRNA guide region is primarily recognized by the REC lobe. The backbone phosphate groups of the guide region (nucleotides 2, 4–6, and 13–20) interact with the REC1 domain (Arg165, Gly166, Arg403, Asn407, Lys510, Tyr515, and Arg661) and the bridge helix (Arg63, Arg66, Arg70, Arg71, Arg74, and Arg78). The 20-hydroxyl groups of G1, C15, U16, and G19 hydrogen bond with Val1009, Tyr450, Arg447/Ile448, and Thr404, respectively. [0253] A mutational analysis demonstrated that the R66A, R70A, and R74A mutations on the bridge helix markedly reduced the DNA cleavage activities, highlighting the functional significance of the recognition of the sgRNA ‘‘seed’’ region by the bridge helix. Although Arg78 and Arg165 also interact with the ‘‘seed’’ region, the R78A and R165A mutants showed only moderately decreased activities. These results are consistent with the fact that Arg66, Arg70, and Arg74 form multiple salt bridges with the sgRNA backbone, whereas Arg78 and Arg165 form a single salt bridge with the sgRNA backbone. Moreover, the alanine mutations of the repeat:anti- repeat duplex-interacting residues (Arg75 and Lys163) and the stemloop-1-interacting residue (Arg69) resulted in decreased DNA cleavage activity, confirming the functional importance of the recognition of the repeat:anti-repeat duplex and stem loop 1 by Cas9. [0254] RNA-guided DNA targeting: SpCas9 recognizes the guide:target heteroduplex in a sequence-independent manner. The backbone phosphate groups of the target DNA (nucleotides 1, 9–11, 13, and 20) interact with the REC1 (Asn497, Trp659, Arg661, and Gln695), RuvC (Gln926), and PI (Glu1108) domains. The C2’ atoms of the target DNA (nucleotides 5, 7, 8, 11, 19, and 20) form van der Waals interactions with the REC1 domain (Leu169, Tyr450, Met495, Met694, and His698) and the RuvC domain (Ala728). The terminal base pair of the guide:target heteroduplex (G1:C20’) is recognized by the RuvC domain via end-capping interactions; the sgRNA G1 and target DNA C20’ nucleobases interact with the Tyr1013 and Val1015 side chains, respectively, whereas the 20-hydroxyl and phosphate groups of sgRNA G1 interact with Val1009 and Gln926, respectively. [0255] Repeat:Anti-Repeat duplex recognition: The nucleobases of U23/A49 and A42/G43 hydrogen bond with the side chain of Arg1122 and the main-chain carbonyl group of Phe351, respectively. The nucleobase of the flipped U44 is sandwiched between Tyr325 and His328, with
its N3 atom hydrogen bonded with Tyr325, whereas the nucleobase of the unpaired G43 stacks with Tyr359 and hydrogen bonds with Asp364. [0256] The nucleobases of G21 and U50 in the G21:U50 wobble pair stack with the terminal C20:G10 pair in the guide:target heteroduplex and Tyr72 on the bridge helix, respectively, with the U50 O4 atom hydrogen bonded with Arg75. Notably, A51 adopts the syn conformation and is oriented in the direction opposite to U50. The nucleobase of A51 is sandwiched between Phe1105 and U63, with its N1, N6, and N7 atoms hydrogen bonded with G62, Gly1103, and Phe1105, respectively. [0257] Stem-loop recognition: Stem loop 1 is primarily recognized by the REC lobe, together with the PI domain. The backbone phosphate groups of stem loop 1 (nucleotides 52, 53, and 59– 61) interact with the REC1 domain (Leu455, Ser460, Arg467, Thr472, and Ile473), the PI domain (Lys1123 and Lys1124), and the bridge helix (Arg70 and Arg74), with the 20-hydroxyl group of G58 hydrogen bonded with Leu455. A52 interacts with Phe1105 through a face-to-edge p-p stacking interaction, and the flipped U59 nucleobase hydrogen bonds with Asn77. [0258] The single-stranded linker and stem loops 2 and 3 are primarily recognized by the NUC lobe. The backbone phosphate groups of the linker (nucleotides 63–65 and 67) interact with the RuvC domain (Glu57, Lys742, and Lys1097), the PI domain (Thr1102), and the bridge helix (Arg69), with the 20-hydroxyl groups of U64 and A65 hydrogen bonded with Glu57 and His721, respectively. The C67 nucleobase forms two hydrogen bonds with Val1100. [0259] Stem loop 2 is recognized by Cas9 via the interactions between the NUC lobe and the non-Watson-Crick A68:G81 pair, which is formed by direct (between the A68 N6 and G81 O6 atoms) and water-mediated (between the A68 N1 and G81 N1 atoms) hydrogen-bonding interactions. The A68 and G81 nucleobases contact Ser1351 and Tyr1356, respectively, whereas the A68:G81 pair interacts with Thr1358 via a water-mediated hydrogen bond. The 20-hydroxyl group of A68 hydrogen bonds with His1349, whereas the G81 nucleobase hydrogen bonds with Lys33. [0260] Stem loop 3 interacts with the NUC lobe more extensively, as compared to stem loop 2. The backbone phosphate group of G92 interacts with the RuvC domain (Arg40 and Lys44), whereas the G89 and U90 nucleobases hydrogen bond with Gln1272 and Glu1225/Ala1227, respectively. The A88 and C91 nucleobases are recognized by Asn46 via multiple hydrogen- bonding interactions.
[0261] Cas9 proteins smaller than SpCas9 allow more efficient packaging of nucleic acids encoding CRISPR systems, e.g., Cas9 and sgRNA into one rAAV (“all-in-one-AAV”) particle. In addition, efficient packaging of CRISPR systems can be achieved in other viral vector systems (i.e., lentiviral, hd-AAV, etc.) and non viral vector systems (i.e., lipid nanoparticle). Small Cas9 proteins can be advantageous for multidomain-Cas-nuclease-based systems for prime editing. Well characterized smaller Cas9 proteins include Staphylococcus aureus (SauCas9, 1053 amino acid residues) and Campylobacter jejuni (CjCas9, 984 amino residues). However, both recognize longer PAMs, 5′-NNGRRT-3′ for SauCas9 (R = A or G) and 5′-NNNNRYAC-3′ for CjCas9 (Y = C or T), which reduces the number of uniquely addressable target sites in the genome, in comparison to the NGG SpCas9 PAM. Among smaller Cas9s, Schmidt et al. identified Staphylococcus lugdunensis (Slu) Cas9 as having genome-editing activity and provided homology mapping to SpCas9 and SauCas9 to facilitate generation of nickases and inactive (“dead”) enzymes (Schmidt et al., 2021, Improved CRISPR genome editing using small highly active and specific engineered RNA-guided nucleases. Nat Commun 12, 4219. doi.org/10.1038/s41467-021- 24454-5) and engineered nucleases with higher cleavage activity by fragmenting and shuffling Cas9 DNAs. The small Cas9s and nickases are useful in the instant disclosure. [0262] Besides dead Cas9 and Cas9 nickase variants, the Cas9 proteins used herein may also include other “Cas9 variants” having at least about 70% identical, at least about 80% identical, at least about 90% identical, at least about 95% identical, at least about 96% identical, at least about 97% identical, at least about 98% identical, at least about 99% identical, at least about 99.5% identical, or at least about 99.9% identical to any reference Cas9 protein, including any wild type Cas9, or mutant Cas9 (e.g., a dead Cas9 or Cas9 nickase), or fragment Cas9, or circular permutant Cas9, or other variant of Cas9 disclosed herein or known in the art. In some embodiments, a Cas9 variant may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 or more amino acid changes compared to a reference Cas9. In some embodiments, the Cas9 variant comprises a fragment of a reference Cas9 (e.g., a gRNA binding domain or a DNA-cleavage domain), such that the fragment is at least about 70% identical, at least about 80% identical, at least about 90% identical, at least about 95% identical, at least about 96% identical, at least about 97% identical, at least about 98% identical, at least about 99% identical, at least about 99.5% identical, or at least about 99.9% identical to the corresponding fragment of wild type Cas9. In some embodiments, the fragment is at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least
85%, at least 90%, at least 95% identical, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% of the amino acid length of a corresponding wild type Cas9. [0263] In some embodiments, the disclosure also may utilize Cas9 fragments that retain their functionality and that are fragments of any herein disclosed Cas9 protein. In some embodiments, the Cas9 fragment is at least 100 amino acids in length. In some embodiments, the fragment is at least 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, or at least 1300 amino acids in length. [0264] In various embodiments, the prime editors disclosed herein may comprise one of the Cas9 variants described as follows, or a Cas9 variant thereof having at least about 70% identical, at least about 80% identical, at least about 90% identical, at least about 95% identical, at least about 96% identical, at least about 97% identical, at least about 98% identical, at least about 99% identical, at least about 99.5% identical, or at least about 99.9% identical to any reference Cas9 variants. 6.2.1. Table 4. Cas9 Orthologs.










































[0301] In certain embodiments, the one or more integration recognition sites is specific for a serine integrase other than BxB1. [0302] In some embodiments, the integration enzyme is selected from one of the about 27,000 Serine integrases described in International Patent Publication No. WO 2023/070031A2, which is hereby incorporated by reference in its entirety.
6.9. Split Gene Editor Guide RNA Compositions [0303] The present disclosure contemplates a split guide RNA comprised of two or more polynucleotides that are capable of forming a guide RNA complex (see Liu et al; doi: 10.1038/s41587-022-01255-9 the entirety of which is incorporated by reference herein). In some embodiments, the guide RNA may be a guide RNA complex, wherein the guide RNA complex is comprised of at least two polynucleotide components. In certain embodiments, the guide RNA complex is comprised of a first polynucleotide component and a second polynucleotide component. In certain embodiments, the first polynucleotide component comprises a spacer complementary to a target first genomic site and a scaffold capable of binding to a DNA binding nickase, and wherein the second polynucleotide component comprises a reverse transcriptase template comprised of at least an integrase target recognition site, a primer binding site and a RNA- protein recruitment domain. In some embodiments, the RNA-protein recruitment domain is a MS2 hairpin. [0304] In some embodiments, at least one of the first polynucleotide component and the second polynucleotide component are circularized. In some embodiments, circularization is mediated by a ribozyme or ligase. In some embodiments, circularization is mediated by covalently or non-covalently linking the 5’ and 3’ termini. [0305] In certain embodiments, the guide RNA or the guide RNA complex further comprises one or more of an RNA-protein recruitment domain, RNA-RNA recruitment domain, a transcriptional termination signal, a reverse transcription termination signal, an RNA ribozyme, or a chemical linker. [0306] In typical embodiments, one or more guide RNA complex is comprised in one or more RNA polynucleotides or DNA polynucleotides. 6.10. Guide RNA Compositions for Dual Guide RNA Systems [0307] In some embodiments, the guide RNA or the guide RNA complex reverse transcriptase template encodes for a first single-stranded DNA sequence (i.e., a first DNA flap) that contains a complementary region to a second single-stranded DNA sequence (i.e., a second DNA flap) encoded by a second guide RNA comprised of a reverse transcriptase template. In certain embodiments, the complementary region between the first and second single-stranded DNA sequences is comprised of more than 5 consecutive bases of an integrase target recognition site. In certain embodiments, the complementary region between the first and second single-stranded DNA sequences is comprised of more than 10 consecutive bases of an integrase target recognition
site. In certain embodiments, the complementary region between the first and second single- stranded DNA sequences is comprised of more than 20 consecutive bases of an integrase target recognition site. In certain embodiments, the complementary region between the first and second single-stranded DNA sequences is comprised of more than 30 consecutive bases of an integrase target recognition site. Use of two guide RNAs that are (or encode DNA that is) partially complementarity to each other and comprised of consecutive bases of an integrase target recognition site are referred to as dual, paired, annealing, complementary, or twin attachment site- containing guide RNAs (atgRNAs). In certain embodiments, use of two guide RNAs that are (or encode DNA that is) full complementarity to each other and comprised of consecutive bases of an integrase target recognition site are referred to as dual, paired, annealing, complementary, or twin attachment site-containing guide RNAs (atgRNAs). [0308] In some embodiments, the integrase target recognition site is an Bxb1 attB or attP sequence. In some embodiments, the att-site central dinucleotide is not GT or CA. [0309] In typical embodiments, one or more guide RNA or the guide RNA complex is comprised in one or more RNA polynucleotides or DNA polynucleotides. [0310] In typical embodiments, the one or more guide RNA complex is a split guide RNA complex or split guide RNA system. In typical embodiments, the one or more guide RNA complex is a split atgRNA complex or split atgRNA system. [0311] A non-limiting example of a dual gRNA (i.e., dual atgRNA system) is as described in FIG.5. 6.11. Programmable Gene Insertion within a Pleiopluripotent Cell Genome [0312] Described herein is a method of editing a pleiopluripotent cell genome. In typical embodiments, the pleiopluripotent cells are edited using, at least in part, the information provided in FIGs.1-5. In some embodiments, editing the pleiopluripotent cell genome results in a cell that, following differentiation and transplantation into a subject, is capable of evading a subject’s immune system (e.g., encoding for one or more exogenous polypeptides that modulate immune response) but safeguarded from runaway expansion (e.g., inducible suicide genes) (see, e.g., FIG. 2). In some embodiments, the methods described herein are designed so that beacons (and ultimately the donor polynucleotide templates) are targeted to genomic loci with the aim of reducing expression (e.g., knocking out) of the gene associated with the particular genomic locus being targeted while also serving as a genomic locus suitable for expression of the aforementioned
transgenes (e.g., exogenous polypeptides capable of modulating an immune response, inducible suicide genes, or a combination thereof). The pleiopluripotent cell genome can be further modified to include additional integration recognition sites (i.e., landing pads and beacons) incorporated into the genome for integrating additional polynucleotides encoding therapeutic agents. Example 10 provides a non-limiting exemplary method for generating pleiopluripotent stem cells having a beacon (integration recognition site) in each of the B2M, CIITA, TRAC, and AAVS1 loci. The pleiopluripotent stem cells can then be used for programmable gene insertion. In some cases, this achieved using multiplex programmable gene insertion, for example, where a different donor polynucleotide template is inserted into each beacon site-specifically placed into the aforementioned loci (see, e.g., Example 11). The resulting genetically modified pleiopluripotent cells can be differentiated to a non-pleiopluripotent cell (e.g., a hematopoietic cell, a neuronal cell, a cardiac cell, or a pancreatic cell) and used as a source of material for allogeneic cell therapy. [0313] In a typical embodiment, a method of generating pleiopluripotent cells includes site- specifically incorporating at least a first integration recognition site into the genome of a pleiopluripotent cell. [0314] In some embodiments, site-specifically incorporating the at least first integration recognition site is effected by introducing into the pleiopluripotent stem cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein or a prime editor fusion protein or a polynucleotide encoding a prime editor fusion protein; (ii) at least a first pair of guide RNAs, wherein the first paired guide RNAs have domains that are capable of guiding the gene editor protein or prime editor fusion protein to nick the pleiopluripotent stem cell genome at sites respectively flanking the specific incorporation site, and at least one of the two paired guide RNAs is an atgRNA that further includes a reverse transcriptase (RT) template that comprises at least a portion of the first integration recognition site, and the atgRNAs collectively encode the entirety of the first integration recognition site, whereby the first integration recognition site is site- specifically incorporated into the genome of the pleiopluripotent stem cell. [0315] In some embodiments, the at least first pair of guide RNAs comprise: (i) the first of the two paired guide RNAs is a first atgRNA that further includes a first RT template that comprises at least a portion of the first integration recognition site; and (ii) a second of the two paired guide RNAs is a second atgRNA that further includes a second RT template that comprises at least a portion of the first integration recognition site, wherein the first atgRNA and the second atgRNAs collectively encode the entirety of the first integration recognition site.
[0316] In some embodiments, the at least first pair of guide RNAs comprise: (i) the first of the two paired guide RNAs is an atgRNA that further includes an RT template that comprises at least a portion of the first integration recognition site, wherein the atgRNA encodes the entirety of the first integration recognition site; and (ii) a second of the two paired guide RNAs is a nicking gRNA. [0317] In some embodiments, the methods include incorporating a plurality of integration recognition sites into the genome of a pleiopluripotent cell. In some embodiments, the method includes incorporating two integration recognition sites, three integration recognition sites, four integration recognition sites, five integration recognition sites, six integration recognition sites, seven integration recognition sites, eight integration recognition sites, nine integration recognition sites, or ten or more integration recognition sites into the genome of a pleiopluripotent cell. In some embodiments, each of the additional integration recognition sites (e.g., second, third, fourth, fifth, sixth, seventh, eighth, ninth, or tenth or more) are an orthogonal pair with an integration recognition site in one or more additional donor polynucleotides. [0318] In another embodiment, a method of generating pleiopluripotent cells includes (a) site- specifically incorporating at least a first integration recognition site into the genome of a pleiopluripotent cell, wherein site-specifically incorporating the at least first integration recognition site is effected by introducing into the pleiopluripotent stem cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein or a prime editor fusion protein or a polynucleotide encoding a prime editor fusion protein; (ii) at least a first pair of guide RNAs, wherein the first paired guide RNAs have domains that are capable of guiding the gene editor protein or prime editor fusion protein to nick the pleiopluripotent stem cell genome at sites respectively flanking the specific incorporation site, and at least one of the two paired guide RNAs is an atgRNA that further includes a reverse transcriptase (RT) template that comprises at least a portion of the first integration recognition site, and the atgRNAs collectively encode the entirety of the first integration recognition site, whereby the first integration recognition site is site- specifically incorporated into the genome of the pleiopluripotent stem cell; and (b) integrating at least a first donor polynucleotide template into the pleiopluripotent cell genome at the first incorporated integration recognition site, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the at least one incorporated integration recognition site by the integrase; thereby producing a second generation
pleiopluripotent cell. In some embodiments, incorporation of the integration recognition site into the pleiopluripotent cell genome is performed concurrently with integration of the donor polynucleotide template into the pleiopluripotent cell genome. [0319] In some embodiments, an at least first integration recognition site is incorporated into the genome of the pleiopluripotent cell using a homology directed repair, homology-independent target insertion (HITI), retrotransposon-mediated integration, viral vector-mediated integration (e.g., lentivirus), transposon-mediated integration (e.g., sleeping beauty), and/or recombinase- mediated integration (e.g., serine recombinase fC31 integrase). In such embodiments, at least a first donor polynucleotide template can be integrated into the genome of the pleiopluripotent cell at the at least first incorporated recognition site using an integrase. [0320] In another embodiment, a method of generating a pleiopluripotent cell (e.g., a second generation pleiopluripotent cell) includes integrating, into the genome of the pleiopluripotent cell at an at least first incorporated recognition site, at least a first donor polynucleotide template, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the at least one incorporated genomic integration recognition sites by the integrase; thereby producing a second generation pleiopluripotent cell. [0321] In another embodiment, a method of generating a pleiopluripotent cell (e.g., a third generation pleiopluripotent cell) includes integrating, into the genome of the pleiopluripotent cell at an at least first incorporated recognition site, at least a first donor polynucleotide template, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the at least one incorporated genomic integration recognition sites by the integrase; and (b) site- specifically incorporating a second integration recognition site into the genome of the pleiopluripotent cell, thereby producing a third generation pleiopluripotent cell. [0322] In another embodiment, a method of generating a pleiopluripotent cell (e.g., a fourth generation pleiopluripotent cell) includes integrating, into the genome of the pleiopluripotent cell at an at least the first incorporated recognition site, at least a first donor polynucleotide template, by introducing into the cell: (i) the first donor polynucleotide template, wherein the first donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and
(ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the at least one incorporated genomic integration recognition sites by the integrase; (b) site- specifically incorporating a second integration recognition site into the genome of the pleiopluripotent cell; and (c) integrating a second donor polynucleotide template into the pleiopluripotent cell genome at the second incorporated integration recognition site, by delivering into the cell: (i) the second donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more integration recognition sites orthogonal to the second integration recognition site, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the second incorporated genomic integration recognition sites by the integrase; thereby producing a fourth generation pleiopluripotent cell. In some embodiments, incorporation of the second integration recognition site into the pleiopluripotent cell genome is performed concurrently with integration of the second donor polynucleotide template into the pleiopluripotent cell genome. [0323] In some embodiments, an integration recognition site (i.e., beacon) is incorporated into a pleiopluripotent cell genome by delivering into the cell: (i) a gene editor protein (or a polynucleotide encoding a gene editor protein) or a prime editor fusion protein (or a polynucleotide encoding a prime editor fusion protein), wherein the gene editor protein or prime editor fusion protein is capable of incorporating the integration recognition site into the genome, and (ii) two guide RNAs (e.g., two atgRNAs), wherein each of the two guide RNA encodes all or part of an integrase target recognition site. Further, the method includes integrating a donor polynucleotide template into the pleiopluripotent cell genome at the incorporated target recognition site by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of an integration target site, and an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the incorporated integration recognition site by the integrase, thereby producing a genetically modified pleiopluripotent cell (e.g., a second generation pleiopluripotent cell). In some embodiments, incorporation of the integration recognition site (i.e., beacon) into the pleiopluripotent cell genome is performed concurrently with integration of the donor polynucleotide template into the pleiopluripotent cell genome. [0324] In some embodiments, an integration recognition site (i.e., beacon) is incorporated into a pleiopluripotent cell genome by delivering into the cell: (i) a gene editor protein (or a polynucleotide encoding a gene editor protein) or a prime editor fusion protein (or a polynucleotide encoding a prime editor fusion protein), wherein the gene editor protein or prime editor fusion
protein is capable of incorporating the integration recognition site into the genome, and (ii) two guide RNA complexes (e.g., two complexes each comprising an atgRNA), wherein each of the two guide RNA complexes is comprised of at least one polynucleotide that encodes all or part of an integrase target recognition site. Further, the method includes integrating a donor polynucleotide template into the pleiopluripotent cell genome at the incorporated target recognition site by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of an integration target site, and an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the incorporated integration recognition site by the integrase, thereby producing a genetically modified pleiopluripotent cell (e.g., a second generation pleiopluripotent cell). In some embodiments, incorporation of the integration recognition site (i.e., beacon/beacon placement) into the pleiopluripotent cell genome is performed concurrently with integration of the donor polynucleotide template into the pleiopluripotent cell genome. [0325] In some embodiments, an integration recognition site (i.e., beacon/beacon placement) is incorporated into a pleiopluripotent cell genome by delivering into the cell: (i) a gene editor protein (or a polynucleotide encoding a gene editor protein) or a prime editor fusion protein (or a polynucleotide encoding a prime editor fusion protein), wherein the gene editor protein or prime editor fusion protein is capable of incorporating the integration recognition site into the genome, (ii) one or more guide RNA, wherein the one or more guide RNA encodes an integrase target recognition site (i.e., atgRNA), and (iii) optionally, a nicking guide RNA (ngRNA). Further, integrating a donor polynucleotide template into the pleiopluripotent cell genome at the incorporated target recognition site by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of an integration target site, and an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the incorporated integration recognition site by the integrase, thereby producing a genetically modified pleiopluripotent cell (e.g., a second generation pleiopluripotent cell). In some embodiments, incorporation of the integration recognition site (i.e., beacon/beacon placement) into the pleiopluripotent cell genome is performed concurrently with integration of the donor polynucleotide template into the pleiopluripotent cell genome. [0326] In some embodiments, an integration recognition site (i.e., beacon/beacon placement) is incorporated into a pleiopluripotent cell genome by delivering into the cell: (i) a gene editor protein (or a polynucleotide encoding a gene editor protein) or a prime editor fusion protein (or a polynucleotide encoding a prime editor fusion protein), wherein the gene editor protein or prime
editor fusion protein is capable of incorporating the integration recognition site into the genome, (ii) one or more guide RNA complex, wherein the one or more guide RNA complex is comprised of at least one polynucleotide that encodes an integrase target recognition site (i.e., atgRNA), and (iii) optionally, a nicking guide RNA (ngRNA). Further, integrating a donor polynucleotide template into the pleiopluripotent cell genome at the incorporated target recognition site by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of an integration target site, and an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent cell at the incorporated integration recognition site by the integrase, thereby producing a genetically modified pleiopluripotent cell (e.g., a second generation pleiopluripotent cell). In some embodiments, incorporation of the integration recognition site (i.e., beacon/beacon placement) into the pleiopluripotent cell genome is performed concurrently with integration of the donor polynucleotide template into the pleiopluripotent cell genome. [0327] In certain embodiments, the pleiopluripotent cell is a pluripotent stem cell. In some embodiments, the pluripotent stem cell is an embryonic stem cell or an induced pluripotent stem cell. In some embodiments, the pleiopluripotent cell is a human cell. 6.11.1. Knockout of HLA Class I and/or Class II proteins [0328] In certain embodiments, the pleiopluripotent comprises a genetic perturbation that results in reduction of an allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. In some embodiments, at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. In some embodiments, the pleiopluripotent cell includes a plurality of integration recognition sites at least one of which is incorporated into the pleiopluripotent cell genome at a locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. Non-limiting examples of loci, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell, are as described in U.S. Patent No. 10,968,426, which is herein incorporated by reference in its entirety. [0329] In certain embodiments, the pleiopluripotent stem cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a
combination thereof. In such cases, the deletion or reduced expression results from knockout or knockdown using base editing, prime editing, other CRISPR/Cas9-mediated methods, TALE- based methods, Zinc Finger Nuclease-based methods, siRNA, miRNA, RNAi, or a combination thereof. In some embodiments, the pleiopluripotent stem cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof as the result of knockout or knockdown of genes expressed from one or more chromosomal regions selected from: HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA- DQ. As described herein, in some embodiments, the pleiopluripotent stem cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof, as a result of incorporation of one or more integration recognition sites into a genomic loci that when disrupted leads to deletion or reduced expression of the associated gene. [0330] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. In such cases, the pleiopluripotent cell has reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. Additionally, incorporation of the at least first integration recognition site results in reduction of a potential allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell (when administered to a patient in need thereof). [0331] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at a chromosomal region selected from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. In such cases, the pleiopluripotent cell has reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. Additionally, incorporation of the at least first integration recognition site results in reduction of a potential allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell (when administered to a patient in need thereof). [0332] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at a locus selected from B2M locus, CIITA locus, HLA-A locus, HLA- B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, and RFXANK locus. In such cases, incorporation of the at least first integration recognition site results in reduction of a potential allogeneic immune response to the pleiopluripotent stem cell
or a cell matured from the pleiopluripotent stem cell (when administered to a patient in need thereof). [0333] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at the B2M locus. In such cases, incorporation of the at least first integration recognition site at the B2M locus results in reduction of a potential allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell (when administered to a patient in need thereof). [0334] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at the CIITA locus. In such cases, incorporation of the at least first integration recognition site at the CIITA locus results in reduction of a potential allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell (when administered to a patient in need thereof). [0335] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at locus associated with blood group antigens, disruption of which is capable of reducing expression of the blood group antigens by the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. In some embodiments, at least one of the at least first integration recognition sites is incorporated into the genome at an alleles of the ABO gene (alpha 1-3-N-acetylgalactosaminyltransferase and alpha 1-3-galactosyltransferase), including, without limitation ABO*A1.01 and ABO* B.01. A non-limiting example of loci, disruption of which is capable of reducing expression of the blood group antigens by the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell, are as described in U.S. Patent No.11,162,079, which is herein incorporated by reference in its entirety. [0336] In some embodiments, the pleiopluripotent cell is an iPSC derived from a healthy donor in order to minimize immunity against ABO antigens. In some embodiments, the pleiopluripotent cell is an iPSC derived from a healthy donor with blood type O. 6.11.2. Incorporation of Integration Recognition Sites into the Genome of a Pleiopluripotent Stem Cell [0337] In some embodiments, an integration recognition site is incorporated (i.e., beacon placement) into a pleiopluripotent cell genome using a single atgRNA and a single nicking guide RNA (ngRNA) (see, e.g., FIG. 5). In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome using two atgRNAs (dual atgRNAs) (see, e.g., FIG. 5). Beacon placement efficiency can be determined, for example, by a two-color digital
droplet PCR assay that compares signal from no-insertion amplicons (i.e., wild type) with signal from beacon inserted/placed amplicons. Beacon placement efficiency can be determined, for example, by amplicon-sequencing (amp-seq). [0338] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90% or greater. [0339] In some embodiments, at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a locus encoding an exon. In such embodiments, the exon is coding sequence of a gene of interest, wherein incorporation of the integration recognition site into the exon is capable of reducing or deleting expression of the gene of interest. In some embodiments, incorporation of integration recognition site at one or more exons associated with a gene of interest results in reduced expression of at least 99%, 98%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, or 10% of the gene of interest as compared to a cell where the integration recognition site is not incorporated at one or more exons associated with the gene of interest. [0340] In some embodiments, efficiency of incorporating an integration recognition site into a pleiopluripotent cell genome at an exon of a gene of interest depends on the molar ratio of a single atgRNA and a single ngRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA at about 900 picomoles total of atgRNA plus ngRNA. In some embodiments, an integration recognition site is incorporated into a pluripotent cell genome at an exon of a gene of interest using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA at about 100 to about 1000 picomoles total of atgRNA plus ngRNA and about 1 to about 10 micrograms of mRNA encoding a prime editor protein (or a primer editor fusion protein).
[0341] In some embodiments, efficiency of incorporating an integration recognition site into a pleiopluripotent cell genome at an exon of a gene of interest depends on the molar ratio of each atgRNA in a dual atgRNA method. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest using dual atgRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of each atgRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest using dual atgRNAs at a 1:1 molar ratio of each atgRNA at about 100 to about 1000picomoles total of atgRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest using dual atgRNAs at a 1:1 molar ratio of each atgRNA at about 100 to about 1000 picomoles total of atgRNA and about 1 to about 10 micrograms of mRNA encoding a prime editor protein (or a primer editor fusion protein). [0342] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% using a single atgRNA and a single ngRNA. [0343] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at an exon of a gene of interest at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% using dual atgRNAs. [0344] In some embodiments, the integration recognition site is incorporated at one or more loci associated with HLA Class I proteins, one or more loci associate with HLA Class II proteins, or a combination thereof. In some embodiments, the integration recognition site is incorporated at one or more loci associated with HLA Class I proteins. In some embodiments, the integration target site is incorporated at one or more loci associated with HLA Class II proteins.
[0345] In some embodiments, incorporation of integration recognition site at one or more loci associated with HLA Class I proteins results in reduced expression of the one or more HLA Class I proteins as compared to a cell where the integration recognition site is not incorporated at one or more loci associated with HLA Class I proteins. In some embodiments, incorporation of integration recognition site at one or more loci associated with HLA Class I proteins results in reduced expression of at least 99%, 98%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, or 10% for each of the one or more HLA Class I proteins as compared to a cell where the integration recognition site is not incorporated at one or more loci associated with HLA Class I proteins. [0346] In some embodiments, incorporation of integration target recognition at one or more loci associated with HLA Class II proteins results in reduced expression of the one or more HLA Class II proteins as compared to a cell where the integration recognition site is not incorporated at one or more loci associated with HLA Class II proteins. In some embodiments, incorporation of integration recognition site at one or more loci associated with HLA Class II proteins results in reduced expression of at least 99%, 98%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, or 10% for each of the one or more HLA Class II proteins as compared to a cell where the integration recognition site is not incorporated at one or more loci associated with HLA Class II proteins. [0347] In certain embodiments, the integration recognition site is incorporated at one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. In some embodiments, the integration recognition target site is incorporated at one or more of the B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. In some embodiments, a donor polynucleotide is integrated at one or more incorporated integration target site. [0348] In some embodiments, efficiency of incorporating an integration recognition site into a pleiopluripotent cell genome at the B2M locus depends on the molar ratio of a single atgRNA and a single ngRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA at about 900 picomoles total of atgRNA plus ngRNA. In some
embodiments, an integration recognition site is incorporated into a pluripotent cell genome at the B2M locus using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA at about 100 to about 1000 picomoles total of atgRNA plus ngRNA and about 1 to about 10 micrograms of mRNA encoding a prime editor protein (or a primer editor fusion protein). [0349] In some embodiments, efficiency of incorporating an integration recognition site into a pleiopluripotent cell genome at the B2M locus depends on the molar ratio of each atgRNA in a dual atgRNA method. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus using dual atgRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of each atgRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus using dual atgRNAs at a 1:1 molar ratio of each atgRNA at about 100 to about 1000picomoles total of atgRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus using dual atgRNAs at a 1:1 molar ratio of each atgRNA at about 100 to about 1000 picomoles total of atgRNA and about 1 to about 10 micrograms of mRNA encoding a prime editor protein (or a primer editor fusion protein). [0350] In some embodiments, efficiency of incorporating an integration recognition site into a pleiopluripotent cell genome at the CIITA locus depends on the molar ratio of a single atgRNA and a single ngRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA at about 900 picomoles total of atgRNA plus ngRNA. In some embodiments, an integration recognition site is incorporated into a pluripotent cell genome at the CIITA locus using a single atgRNA and a single ngRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of atgRNA to ngRNA at about 100 to about 1000 picomoles total of atgRNA plus ngRNA and about 1 to about 10 micrograms of mRNA encoding a prime editor protein (or a primer editor fusion protein). [0351] In some embodiments, efficiency of incorporating an integration recognition site into a pleiopluripotent cell genome at the CIITA locus depends on the molar ratio of each atgRNA in a dual atgRNA method. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus using dual atgRNA at a 1:1, 1.5:1, 2:1, 3:1, 1:3:
1:2, 1:1.5 or 1:1 molar ratio of each atgRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus using dual atgRNAs at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of each atgRNA at about 100 to about 1000 picomoles total of atgRNA. In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus using dual atgRNAs at a 1:1, 1.5:1, 2:1, 3:1, 1:3: 1:2, 1:1.5 or 1:1 molar ratio of each atgRNA at about 100 to about 1000 picomoles total of atgRNA and about 1 to about 10 micrograms of mRNA encoding a prime editor protein (or a primer editor fusion protein). [0352] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% using a single atgRNA and a single ngRNA. [0353] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the CIITA locus at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% using dual atgRNAs. [0354] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% using a single atgRNA and a single ngRNA.
[0355] In some embodiments, an integration recognition site is incorporated into a pleiopluripotent cell genome at the B2M locus at an efficiency of at least 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% using dual atgRNAs. [0356] In certain embodiments, an integration recognition site is specific for an integrase. In some embodiments, the integration recognition site is specific for a recombinase or transposase. In typical embodiments, the integration recognition site is an attB or attP site. In some embodiments, the integration recognition site is a modified or orthogonal attB or attP site. In certain embodiments, the integrase target recognition site is a Bxb1 attB or attP sequence. In some embodiments, the att-site central dinucleotide is not GT or CA. [0357] In some embodiments, the integration recognition site is comprised of 38 or 46 nucleotides. In some embodiments, the integration recognition site is less than 46 nucleotides. In some embodiments, the integration recognition site is less than 40 nucleotides. In some embodiments, the integration recognition site is less than 35 nucleotides. In some embodiments, the integration recognition site is less than 30 nucleotides. In some embodiments, the integration recognition site is less than 25 nucleotides. [0358] In some embodiments, the one or more guide RNA or the one or more guide RNA complex comprises a chemical modification. In certain embodiments, the chemical modification is selected from one or more of a 2’ O-methyl and phosphorothioate. [0359] Sequences of guide RNAs (i.e., attachment site-containing guide RNAs) suitable for partial replacement use in embodiments of the disclosure are presented below. In the below table: [0360] As described herein non-modified RNA are entered as ‘r_’. For example, as rA or rU. As described herein, 2’ O-methyl RNA are entered as ‘m_’. As described herein, phosphorothioated RNA are entered as ‘r_*’. As described herein, phosphorothioated 2’ O-methyl RNA are entered as ‘m_*’ [0361] Table 12 includes dual atgRNAs for incorporating an integration recognition site at the B2M locus or CIITA locus.
Table 12

Table 12
Table 12

[0362] In typical embodiments, the guide RNA (e.g., atgRNA) for beacon placement comprises, in 5’ to 3’ order, (i) a spacer complementary to a first target genomic site, (ii) a scaffold capable of binding to a DNA binding nuclease or nuclease with nickase activity (or cleaves activity), (iii) a reverse transcriptase template comprised of at least an integrase target recognition site (e.g., all or a portion of an integrase target recognition site), and (iv) a primer binding site. In typical embodiments, the reverse transcriptase template encodes for a first single-stranded DNA sequence or first DNA flap sequence.
6.11.3. Donor Polynucleotide Template [0363] In certain embodiments, a cellular integrated polynucleotide (i.e., donor polynucleotide template) encodes for one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, and one or more adapters (tags), or a combination thereof. (See, e.g., FIG.3A). [0364] In some embodiments, a cellular integrated polynucleotide (i.e., donor polynucleotide template) includes one or more integration recognition sites. In some embodiments, the one or more integration recognition sites encoded in the cellular integrated polynucleotide (i.e., donor polynucleotide template) can be used to integrate a second cellular integrated polynucleotide (e.g., a second donor polynucleotide template) in the genomic loci where the first cellular integrated polynucleotide integrated. In some embodiments, the one or more integration recognition sites encoded in the cellular integrated polynucleotide (i.e., donor polynucleotide template) can be used to excise all or a portion of the cellular integrated polynucleotide integrated into pleiopluripotent cell genome. [0365] In some embodiments, expression of the one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof, is driven by a pleiopluripotent cell-specific regulatory elements (e.g., a promoter, an enhancer, or a combination thereof). Non-limiting examples of pleiopluripotent cell-specific promoters include a Nanog promoter, a Oct4 promoter, an hTERT promoter, and a Sox2 promoter. [0366] In some embodiments, expression of the one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof, is driven by a constitutive promoter. Non-limiting examples of constitutive promoters include CMV, EF1A, SV40, PGK, CAG, and UBC. [0367] In some embodiments, the first donor polynucleotide template integrated into the pleiopluripotent cell genome is at least 1 kilobase (kb), at least 2kb, at least 3kb, at least 4kb, at least 5kb, at least 6kb, at least 7kb, at least 8kb, at least 9kb, at least 10kb, at least 11kb, at least 12kb, at least 13kb, at least 14kb, at least 15kb, at least 16kb, at least 17kb, at least 18kb, at least 19kb, at least 20kb, at least 21kb, at least 22kb, at least 23kb, at least 24kb, at least 25kb, at least 26kb, at least 27kb, at least 28kb, at least 29kb, at least 30kb, at least 31kb, at least 32kb, at least 33kb, at least 34kb, or at least 35kb or more. In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome is at least 5 kilobases (kb). In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome
is at least 10 kilobases (kb). In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome is at least 15 kilobases (kb). In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome is at least 20 kilobases (kb). In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome is at least 25 kilobases (kb). In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome is at least 30 kilobases (kb). In some embodiments, the first donor polynucleotide template integrated into pleiopluripotent cell genome is at least 35 kilobases (kb). [0368] In some embodiments, the first donor polynucleotide template integrated into the pleiopluripotent cell genome is at least at least 1 kilobase (kb), at least 2kb, at least 3kb, at least 4kb, at least 5kb, at least 6kb, at least 7kb, at least 8kb, at least 9kb, at least 10kb, at least 11kb, at least 12kb, at least 13kb, at least 14kb, at least 15kb, at least 16kb, at least 17kb, at least 18kb, at least 19kb, at least 20kb, at least 21kb, at least 22kb, at least 23kb, at least 24kb, at least 25kb, at least 26kb, at least 27kb, at least 28kb, at least 29kb, at least 30kb, at least 31kb, at least 32kb, at least 33kb, at least 34kb, or at least 35kb or more. In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 5 kilobases (kb). In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 10 kilobases (kb). In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 15 kilobases (kb). In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 20 kilobases (kb). In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 25 kilobases (kb). In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 30 kilobases (kb). In some embodiments, the second donor polynucleotide template integrated into pleiopluripotent cell genome is at least 35 kilobases (kb). 6.11.3.1 Inducible Suicide Genes [0369] In certain embodiments, the cellular integrated polynucleotide (i.e., donor polynucleotide template) encodes for one or more inducible suicide genes. As used herein, the term “inducible suicide gene” refers to an engineered polypeptide designed to prevent the adverse events of cell therapy. In some embodiments, the inducible suicide gene is conditionally controlled to address adverse events of cell therapy (e.g., safety concerns). Conditional regulation can include control through a small molecule-mediated post-translational activation, tissue-specific regulation, temporal transcriptional regulation, or a combination thereof. The inducible suicide gene could
mediate induction of apoptosis, inhibition of protein synthesis, DNA replication, growth arrest, transcriptional and post-transcriptional genetic regulation and/or antibody-mediated depletion. In some embodiments, the inducible suicide gene is activated by an exogenous molecule, e.g., a prodrug, that when activated, triggers apoptosis and/or cell death of a therapeutic cell. Non- limiting examples of inducible suicide genes include to suicide genes such as caspase 9 (or caspase 3 or 7), herpes simplex virus thymidine kinase (HSV-TK), cytosine deaminase, modified EGFR, nitroreductase, purine nucleoside phosphorylase, horseradish peroxidase, a HER1 transgene, a RQR8 transgene, or a combination thereof. In this strategy, a prodrug (e.g., an exogenous molecule) that is administered in the event of an adverse event is activated by the suicide-gene product and kills the transduced cell. [0370] In one embodiment, the one or more inducible suicide genes is caspase9. In one embodiment, the one or more inducible suicide genes comprises two caspase9 proteins where each caspase9 protein is operably linked to a different promoter sequence (See FIG. 3A). Relying on two different promoters enables both time and tissue specific control over expression of each caspase9 protein. In one embodiment, each caspase 9 protein is fused to a different controllable domain (e.g., FKBP or mFRM and FKBP), thereby generating controllable caspase9 proteins. This enables individual control over activity of each caspase9 protein (see FIG. 4). Activity of a controllable caspase9 proteins is controlled using an exogenous molecule. In one embodiment, the exogenous molecule is AP20187 (or an analog thereof). AP20187 enables homodimerization of Caspase9-FKBP fusions. A non-limiting example, as shown in FIG.4, illustrates caspase9-FKBP fusions where expression is driven by a nanog promoter. In this case, the caspase9 FKBP protein is expressed while the cells are in a pluripotent state. Contacting the cell with AP20187 during the pluripotent state results in cell death. In some embodiments, the exogenous molecule is AP21967 (or an analog thereof). A non-limiting example, as shown in FIG.4, illustrate caspase9-FKBP and caspase9-mFRB where expression is driven by a beta-actin promoter (or another constitutively active promoter). In this case, the Caspase9-FKBP and Caspase9-mFRB fusion are expressed constitutively. Therefore, contacting the cells with the AP21967 results in cell death. Either AP20187 and/or AP21967 can be administered to a subject who was previously been administered cells containing the HSV-TK gene. [0371] In one embodiment, the one or more inducible suicide genes is herpes simplex virus thymidine kinase (HSV-TK). HSV-TK converts ganciclovir into a toxic product and allows selective elimination of cells expressing the HSV-TK gene. Ganciclovir can be administered to a
subject who was previously been administered cells containing the HSV-TK gene. In such cases, ganciclovir is used to eliminate the previously administered cells. [0372] In one embodiment, the donor polynucleotide templates comprise three suicide genes, including a first caspase9 protein fused to a FKBP domain operably linked to a Nanog promoter, a second caspase9 protein used to a mFRB domain and a FKBP domain operably linked to a Beta- actin promoter, and a thymidine kinase (see, e.g. FIG. 3A). In some embodiments, each of the inducible suicide genes is operably linked to a promoter. In some embodiments, the thymidine kinase is linked to one of the caspase9 proteins by a 2A self-cleaving peptide (e.g., a P2A, E2A,T2A, and F2A) or an internal ribosome entry site (IRES) (see, e.g., FIG.3A). [0373] In some embodiments, integrating a donor polynucleotide template encoding one or more inducible suicide genes into the pleiopluripotent cell genome at the one or more incorporated target recognition sites results in increased expression of the one or more inducible suicide genes as compared to a pluripotent stem genome not having a donor polynucleotide template integrated into the cell’s genome at the one or more incorporated target recognition sites. In some embodiments, integrating a donor polynucleotide template encoding one or more inducible suicide genes into the pleiopluripotent cell genome at the one or more incorporated target recognition sites results in increased expression of at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, or more of the one or more inducible suicide genes as compared to a pluripotent stem genome not having a donor polynucleotide template integrated into the cell’s genome at the one or more incorporated target recognition sites. [0374] In some embodiments, the encoded one or more inducible suicide genes further comprises an integrase target recognition site. In some embodiments, the encoded one or more inducible suicide genes further comprises at least two integrase target recognition sites. In certain embodiments, the one or more integrase target recognition sites flank the encoded one or more inducible suicide genes. In certain embodiments, the flanking integrase target recognition sites allow for excision of the one or more inducible suicide genes. 6.11.3.2 Exogenous Polypeptides Capable of Modulating an Immune Response [0375] In certain embodiments, the one or more exogenous polypeptides capable of modulating an immune response prevents an immune response to the pleiopluripotent cells or cells derived therefrom. In some embodiments, the one or more exogenous polypeptides capable of
modulating an immune response prevent an immune response to the pleiopluripotent cells (or cells derived therefrom) by inhibiting, blocking, or preventing recognition of the pleiopluripotent cell by macrophages, T-cells, Natural Killer (NK)-cells, antigen-presenting cells, or a combination thereof. [0376] In some embodiments, the one or more exogenous polypeptides capable of modulating an immune response is selected from: CD47, PDL-1, HLA-E, HLA-G, HACD16, 41BBL, CD3, CD4, CD8, CD137, CD80, and A2AR, or a combination thereof. [0377] In some embodiments, integrating a donor polynucleotide template encoding one or more exogenous polypeptides capable of modulating an immune response into the pleiopluripotent cell genome at the one or more incorporated target recognition sites results in increased expression of the one or more polypeptides capable of modulating an immune response as compared to a pluripotent stem genome not having a donor polynucleotide template integrated into the cell’s genome at the one or more incorporated target recognition sites. In some embodiments, integrating a donor polynucleotide template encoding one or more exogenous polypeptides capable of modulating an immune response into the pleiopluripotent cell genome at the one or more incorporated target recognition sites results in increased expression of at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, or more of the one or more inducible suicide genes as compared to a pluripotent stem genome not having a donor polynucleotide template integrated into the cell’s genome at the one or more incorporated target recognition sites. [0378] In certain embodiments, the cellular integrated polynucleotide (i.e., donor polynucleotide template) encodes for two or more exogenous polypeptides capable of modulating an immune response where the sequence encoding the two or more exogenous polypeptides are separated by a 2A self-cleaving peptide (e.g., a P2A, E2A,T2A, and F2A). In other embodiments, the sequences encoding the two or more exogenous polypeptides are separated by an internal ribosome entry site (IRES). In some embodiments, a cellular integrated polynucleotide includes: CD47, PDL-1, and B2M-HLA-E. In such cases, the sequences encoding CD47, PDL-1 and B2M- HLA-E are separated by either a 2A self-cleaving peptide (e.g., a P2A, E2A,T2A, and F2A) or an IRES sequence. A non-limiting example of a cellular integrated polynucleotide is described in FIG.3A. [0379] In certain embodiments, the encoded one or more exogenous polypeptides capable of modulating an immune response further comprises an integrase target recognition site. In some
embodiments, the encoded one or more exogenous polypeptides capable of modulating an immune response further comprises at least two integrase target recognition sites. In certain embodiments, the one or more integrase target recognition sites flank the encoded one or more exogenous polypeptides capable of modulating an immune response. In certain embodiments, the flanking integrase target recognition sites allow for excision of the one or more exogenous polypeptides capable of modulating an immune response. [0380] In some embodiments, the one or more exogenous polypeptides capable of modulating an immune response are capable of serving as a safety switch target. In some embodiments, the one or more exogenous polypeptides can be targeted with an antibody that is capable of specifically binding to the one or more exogenous polypeptides, thereby blocking the polypeptides ability to prevent an immune response to the pleiopluripotent cells, or cells derived therefrom. For example, a pleiopluripotent cell comprising an exogenous CD47 on it surface can be contacted with an anti- CD47 antibody, wherein the anti-CD47 antibody blocks CD47 interaction with macrophage signal regulatory protein (SIRPα), thereby allowing recognition and elimination of the cell by macrophages. In another example, the pleiopluripotent cell comprising an exogenous PD-L1 on it surface can be contacted with an anti-PD-L1 antibody, wherein the anti-PD-L1 antibody blocks PD-L1 interaction with PD-1, thereby allowing recognition and elimination of the cell by T cells. 6.11.3.3 Adapters/Tags [0381] In some embodiments, a first or second cellular integrated polynucleotide (i.e., a first or second donor polynucleotide template) includes a sequence encoding a tag that enables isolation of the pleiopluripotent cell. The tag can be a stand-alone molecule such as a polypeptide expressed on the surface of the pleiopluripotent cell or a cell-derived from the pleiopluripotent cell. Non- limiting example of stand-alone tags includes non-natively expressed receptors (e.g., nerve truncated growth factor receptor and truncated nerve growth factor receptor). [0382] In other cases, the tag can be an amino acid sequence fused to an amino acid sequence of an endogenous protein that is expressed by a pleiopluripotent cell or a cell-derived from the pleiopluripotent cell. Non-limiting examples of tags that can be used to isolate a cell having a first or second cellular integrated polynucleotide include an ALFA tag system (e.g., SRLEEELRRRLTE (SEQ ID NO: 615)). In one non-limiting example, the ALFA tag is fused to the N-terminus of CD47 (see FIG.3A). [0383] In one embodiment, the first or second cellular integrated polynucleotide includes a sequence encoding an ALFA tag fused to one or more polypeptide expressed on the surface of the
cell (e.g., one of more of the exogenous polypeptides capable of modulating an immune response). In such cases, a nanobody designed to bind specifically to the ALFA can be used to bind and isolate the pleiopluripotent cells having the tag on the surface. In some cases, an ALFA tag can be used to identify pleiopluripotent cells that include the first and/or second cellular integrated polynucleotide integrated into its genome. In some cases, an ALFA nanobody (NbALFA) is fused to one or more polypeptides on the surface of the cell, one or more ALFA tagged polypeptides can be used to engage with NbALFA fusion polypeptides for therapeutic purposes. 6.11.4. Additional Integration Recognition Sites Incorporated into Pleiopluripotent Cell Genome [0384] In some embodiments, an additional integration recognition site is incorporated into a pleiopluripotent cell genome by delivering into the cell: (i) a gene editor protein (or a polynucleotide encoding a gene editor protein) or a prime editor fusion protein (or a polynucleotide encoding a prime editor fusion protein), wherein the gene editor protein or prime editor fusion protein is capable of incorporating the integration recognition site into the genome, (ii) at least a first pair of guide RNAs, wherein the first paired guide RNAs have domains that are capable of guiding the gene editor protein or prime editor fusion protein to nick the pleiopluripotent stem cell genome at sites respectively flanking the specific incorporation site, and at least one of the two paired guide RNAs is an atgRNA that further includes a reverse transcriptase (RT) template that comprises at least a portion of the first integration recognition site, and the atgRNAs collectively encode the entirety of the first integration recognition site, whereby the first integration recognition site is site-specifically incorporated into the genome of the pleiopluripotent stem cell. [0385] In some embodiments, the additional integration recognition site is incorporated into the pleiopluripotent cell genome at a locus encoding an exon. In such embodiments, the exon is coding sequence of a gene of interest, wherein incorporation of the integration recognition site into the exon is capable of reducing or deleting expression of the gene of interest. [0386] In some embodiments, the additional integration recognition is incorporated into the pleiopluripotent cell genome at a locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent cell. Non-limiting examples of loci, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent cell, are described herein.
[0387] Incorporating an additional integration recognition site into a pleiopluripotent cell genome enables subsequent round of genetic modification of the pleiopluripotent cell genome. For example, in a subsequent round of genetic modification, a second donor polynucleotide can be integrated at the genomic locus where the additional integration recognition sites were incorporated in the early round of editing. [0388] In some embodiments, a genetically modified pleiopluripotent cell comprises one, two, three, four, five, six, seven, eight, nine, ten, or more integration recognition sites. In some embodiments, the at least one, at least two, at least three, at least four, at least five or more of the integration recognition sites can be used for placing a second donor polynucleotide template into the pleiopluripotent cell genome. 6.11.5. A Second Donor Polynucleotide Template [0389] In certain embodiments, a second donor polynucleotide template (e.g., a second cellular integrated polynucleotide) that encodes for one or more of the therapeutic agents described herein is incorporated into the pleiopluripotent cell genome. In such cases, the second cellular integrated polynucleotide (i.e., second donor polynucleotide template) can be incorporated into the pleiopluripotent cell genome at an additional integration recognition site (e.g., any of the additional integration recognition sites described herein). [0390] In some embodiments, a second donor polynucleotide template encodes transcription factors, receptors, chimeric antigen receptors, signaling molecules, secreted proteins, cytokines, enzymes, or proteins promoting engraftment, trafficking, homing, viability, self-renewal, and persistence and/or survival of the iPSCs or cells derived from the iPSC. [0391] In some embodiments, a second donor polynucleotide template encodes for one or more of a chimeric antigen receptor, a T cell receptor, a cytokine receptor, a chemokine receptor, or a modified receptor. In some embodiments, the second donor polynucleotide template encodes for an exogenous T cell receptor. In some embodiments, the second cellular integrated polynucleotide encodes for a secreted cytokine. In some embodiments, the second donor polynucleotide template encodes for a recombinant protein. In some embodiments, the second donor polynucleotide template further comprises one or more of a co-stimulatory receptor such suitable co-stimulatory signaling regions are also well known in the art, and include members of the B7/CD28 family such as B7-1, B7-2, E7-H1, B7-H2, E7-H3, B7-H4, B7-H6, B7-H7, BTLA, CD28, CTLA-4, Gi24, ICOS, PD-1, PD-L2 or PDCD6; or ILT/CD85 family proteins such as LILRA3, LILRA4, LILRB1, LILRB2, LILRB3 or LILRB4; or tumor necrosis factor (TNF)
superfamily members such as 4-1BB, BAFF, BAFF R, CD27, CD30, CD40, DR3, GITR, HVEM, LIGHT, Lymphotoxin-alpha, OX40, RELT, TACI, TL1A, TNF-alpha or TNF RII; or members of the SLAM family such as 2B4, BLAME, CD2, CD2F-10, CD48, CD8, CD84, CD229, CRACC, NTB-A or SLAM; or members of the TIM family such as TIM-1, TIM-3 or TIM-4; or other co- stimulatory molecules such as CD7, CD96, CD160, CD200, CD300a, CRTAM, DAP12, Dectin- 1, DPPIV, EphB6, Integrin alpha 4 beta 1, Integrin alpha 4 beta 7/LPAM-1, LAG-3 or TSLP R. [0392] The selection of the co-stimulatory signaling regions may be selected depending upon the particular use intended for the transformed cells. In particular, the co-stimulatory signaling regions selected for those which may work co-operatively or synergistically together. For example, the co-stimulatory signaling regions may be selected from CD28, CD27, ICOS, 4-1BB, OX40, CD30, GITR, HVEM, DR3 or CD40. [0393] In some embodiments, the encoded one or more chimeric antigen receptor, T cell receptor, cytokine receptor, chemokine receptor, or modified receptor, further comprises one or more integrase target recognition site. In some embodiments, the encoded one or more chimeric antigen receptor, T cell receptor, cytokine receptor, chemokine receptor, or modified receptor, further comprises at least two integrase target recognition sites. In certain embodiments, the one or more integrase target recognition sites flank the encoded one or more chimeric antigen receptor, T cell receptor, cytokine receptor, chemokine receptor, or modified receptor. In certain embodiments, the flanking integrase target recognition sites allow for excision of any inserted genetic sequence. [0394] In some embodiments, a first or second donor polynucleotide template encodes one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. In some embodiments, the first or second donor polynucleotide template encodes one or more HLA Class I proteins or one or more HLA Class II proteins that has reduced expression (e.g., due to a mutation or due to genetic ablation using a knockdown-mediated technique) in the pleiopluripotent cell or cell differentiated from the pleiopluripotent cell. In some embodiments, the HLA Class 1 protein is a B2M protein. In some embodiments, a first or second donor polynucleotide template includes an inducible promoter that controls expression of the one or more HLA Class I proteins, the one or more HLA Class II proteins, or a combination thereof. In such cases, the one or more HLA Class I proteins or one or more HLA Class II proteins can be “switched-on” at a later time point. Non-limiting examples of inducible promoter sequences that can be used in the methods described herein include a tetracycline-inducible promoter, an alcohol regulated promoter (e.g., AlcA promoter and AlcR activator), and steroid-regulated promoter (e.g., a LexA promoter and a XVE
activator), a temperature-inducible promoter (e.g., Hsp70 or Hsp90), and a light-inducible promoter (e.g., FixK2 promoter and blue-light sensing protein YFI). In some embodiments, the inducible promoter is a tetracycline inducible promoter. [0395] A non-limiting example of a donor polynucleotide template that can be incorporated into the genome of a pleiopluripotent cell using the methods described herein includes the donor polynucleotide templates are as described in FIGs.3A-3B, FIG.17, and FIG.18 (see also SEQ ID NOs: 616 and 617). [0396] In some embodiments, a first or second cellular integrated polynucleotide (i.e., a first or second donor polynucleotide template) that includes an inducible promoter that controls expression of the one or more HLA Class I proteins, the one or more HLA Class II proteins, or a combination thereof, is incorporated into a pleiopluripotent cell’s genome at locus that allows for inducible gene expression can be “switched-on” at a later time point. Non-limiting criteria for genomic loci that enable inducible gene expression at a later time point include those that remain accessible to transcriptional machinery (i.e., capable of being expressed) when the cell is in a pluripotent state as well as when the cells are differentiated to one or more of the cell types described herein (e.g., a hematopoietic cell, a neuronal cell, a cardiac cell, and a beta-cell). A non- limiting example of a genomic loci that fits this criteria is the CIITA locus. 6.11.6. Safe Harbor Loci and Genomic Safe Harbor [0397] In some embodiments, an integration recognition site (i.e., beacon) is incorporated into a pleiopluripotent cell genome at a safe harbor locus or a genomic safe harbor. In such cases, the donor polynucleotide template is integrated into the pleiopluripotent cell genome at the safe harbor loci or the genomic safe harbor. [0398] In some embodiments, an additional integration recognition site (e.g., a second integration recognition site) is incorporated into a pleiopluripotent cell genome at a safe harbor locus or a genomic safe harbor. In such cases, the second donor polynucleotide template described herein) is integrated into the pleiopluripotent cell genome at the safe harbor loci or the genomic safe harbor. [0399] Safe harbor loci, safe harbor site, and genomic safe can be used interchangeably. In some embodiments, a safe harbor locus is region of the human genome (e.g., intragenic or extragenic regions) that are able to accommodate predictable expression of newly integrated DNA without adverse effects on the host cell or organism. In typical embodiments, a useful safe harbor must
permit sufficient transgene expression to yield desired levels of the proteins encoded in the donor template polynucleotide. In some embodiments, a safe harbor also must not predispose cells to malignant transformation nor alter cellular functions. Non-limiting examples of criteria that describe a safe harbor loci and/or genomic safe harbor include (i) absence of disruption of regulatory elements or genes, as judged by sequence annotation; is an intergenic region in a gene dense area, or a location at the convergence between two genes transcribed in opposite directions; (ii) keep distance to minimize the possibility of long-range interactions between vector-encoded transcriptional activators and the promoters of adjacent genes, particularly cancer-related and microRNA genes; and (iii)ubiquitous transcriptional activity, as reflected by broad spatial and temporal expression patterns (e.g., as measured by expression analysis), chromatin accessibility patterns (e.g., as measured by ATAC-seq), or methylation patterns (e.g., as measured by whole- genome bisulfite sequencing), indicating ubiquitous transcriptional activity. In typical embodiments, it is important for the safe harbor loci or genomic safe harbor to have the potential for ubiquitous expression because pleiopluripotent cells during differentiation experience changes in chromatin accessibility and/or remodeling that can lead to silencing of some loci and potential activation of others. [0400] Non-limiting examples of genomic safe harbor include those as described in Aznauryan et al. (Cell Reports Methods, Discovery and validation of human genomic safe harbor sites for gene and cell therapies, 2(1): 100154 (2022); see Table S1, including Genomic coordinates: chromosome 1: 195338589-195818588 and chromosome 3: 22720711-22761389). [0401] Other non-limiting examples of safe harbor sites include adeno-associated virus site 1 (AAVS1), the chemokine (CC motif) receptor 5 ( CCR5 ) gene locus, the human orthologue of the mouse ROSA26 locus, collagen and FITRP. A frequently used human SHS is the AAVS1 site on chromosome 19q, initially identified as a site for recurrent adeno-associated virus insertion. Another locus comprises the human homolog of the murine Rosa26 locus. Yet another SHS comprises the human H11 locus on chromosome 22. In some cases, a complete gene may be prohibitively large and replacement of an entire gene impractical. 6.11.7. Therapeutic Agents [0402] This disclosure provides compositions and methods for correcting or replacing genes or gene fragments (including introns or exons) or inserting genes in new locations. In certain embodiments, such a method comprises recombination or integration of a therapeutic agent into a
safe harbor site (SHS) (e.g., any of the safe harbor sites described herein). In certain embodiments, a method of the invention comprises recombining corrective gene fragments into a defective locus. [0403] The methods and compositions can be used to target, without limitation, pleiopluripotent cells, for example embryonic stem cells or induced pleiopluripotent cells (iPSCs) cells at various stages of potency. [0404] In certain embodiments, correcting or replacing genes or gene fragment (including introns and exons) includes integrating the corrective gene or fragment (the therapeutic agent) into one or more additional integration recognition sites previously incorporated into the pleiopluripotent cell genome. For example, the genes and targets described herein are encoded in the first donor template nucleotide, the second donor template nucleotide, or both. In such cases, the genes and targets described herein are integrated into the pleiopluripotent cell genome at the corresponding loci in which the integration target recognition sequences have been integrated (e.g., the one or more integration recognition sites or the one or more additional integration recognition sites). [0405] In certain embodiments, methods and compositions of the invention are adapted to differentiate muscle cells to cardiomyocytes for Duchene Muscular Dystrophy (DMD). The dystrophin gene is the largest gene in the human genome, spanning ∼2.3 Mb of DNA. DMD is composed of 79 exons resulting in a 14-kb full-length mRNA. Common mutations include mutations that disrupt the reading frame of generate a premature stop codon. An aspect of DMD that lends it to gene editing as a therapeutic approach is the modular structure of the dystrophin protein. Redundancy in the central rod domain permits the deletion of internal segments of the gene that may harbor loss-of-function mutations, thereby restoring the open reading frame (ORFs). [0406] The following are non-limiting diseases that may be treated utilizing the methods and compositions of the present disclosure: Inherited Retinal Diseases: • Stargardt Disease (ABCA4) • Leber congenital amaurosis 10 (CEP290) • X linked Retinitis Pigmentosa (RPGR) • Autosomal Dominant Retinitis Pigmentosa (RHO) Liver Diseases: • Wilson’s disease (ATP7B)
• Alpha-1 antitrypsin (SERPINA1) Intellectual Disabilities: • Rett Syndrome (MECP2) • SYNGAP1-ID (SYNGAP1) • CDKL5 deficiency disorder (CDKL5) Peripheral Neuropathies: • Charcot-Marie-Tooth 2A (MFN2) Lung Diseases: • Cystic Fibrosis (CFTR) • Alpha-1 Antitrypsin (SERPINA1) Autoimmune diseases: • IgA Nephropathy (Berger’s disease) • Anti-Neutrophil Cytoplasmic Antibody (ANCA) Vasculitis • Systemic Lupus Erythematosus (SLE) / Lupus Nephritis (LN) • Membranous Nephropathy (MN) • C3 glomerulonephritis (C3GN) Blood disorders: • Sickle Cell • Hemophilia • Factor VIII or • Factor IX • Ornithine transcarbamylase deficiency (OTCD) • Homocystinuria (HCU) • Phenylketonuria (PKU) Cancer • Prostate cancer • Renal cell cancer • Thyroid cancer [0407] CFTR (cystic fibrosis transmembrane conductance regulator). The most common cystic fibrosis (CF) mutation F508del removes a single amino acid. In some embodiments,
recombining human CFTR into an SHS of a cell that expresses CFTR F508del is a corrective treatment path. In some embodiments, the methods and systems described herein are used to CF by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing CF. Proposed validation is detection of persistent CFTR mRNA and protein expression in transduced cells. [0408] Sickle cell disease (SCD) is caused by mutation of a specific amino acid — valine to glutamic acid at amino acid position 6. In some embodiments, SCD is corrected by recombination of the HBB gene into a safe harbor site (SHS) and by demonstrating correction in a proportion of target cells that is high enough to produce a substantial benefit. In some embodiments, the methods and systems described herein are used to sickle cell disease by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing the disease. In some embodiments, validation is detection of persistent HBB mRNA and protein expression in transduced cells. [0409] DMD — Duchenne Muscular Dystrophy. The dystrophin gene is the largest gene in the human genome, spanning ∼2.3 Mb of DNA. DMD is composed of 79 exons resulting in a 14- kb full-length mRNA. Common mutations include mutations that disrupt the reading frame of generate a premature stop codon. An aspect of DMD that lends it to gene editing as a therapeutic approach is the modular structure of the dystrophin protein. Redundancy in the central rod domain permits the deletion of internal segments of the gene that may harbor loss-of-function mutations, thereby restoring the open reading frame (ORFs). [0410] In some embodiments, recombination will be into safe harbor sites (SHS). A frequently used human SHS is the AAVS1 site on chromosome 19q, initially identified as a site for recurrent adeno-associated virus insertion. In some embodiments, the site is the human homolog of the e murine Rosa26 locus (pubmed.ncbi.nlm.nih.gov/18037879). In some embodiments, the site is the human H11 locus on chromosome 22. Proposed target cells for recombination include stem cells for example induced pluripotent stem cells (iPSCs) and cells at various stages of differentiation. In some cases, a complete gene may be prohibitively large and replacement of an entire gene impractical. In such instances, rescuing mutants by recombining in corrected gene fragments with the methods and systems described herein is a corrective option. [0411] In some embodiments, correcting mutations in exon 44 (or 51) by recombining in a corrective coding sequence downstream of exon 43 (or 50), using the methods and systems
described herein is a corrective option. Proposed validation is detection of persistent DMD mRNA and protein expression in transduced cells. [0412] F8 (Factor VIII). A large proportion of severe hemophilia A patients harbor one of two types of chromosomal inversions in the FVIII gene. The recombinase technology and methods described herein are well suited to correcting such inversions (and other mutations) by recombining of the FVIII gene into a SHS. [0413] In some embodiments, correcting factor VIII deficiency by recombining the FVIII gene into an SHS is a corrective path. In some embodiments, the methods and systems described herein are used to correct factor VIII deficiency by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing the FIX deficiency. Proposed validation is detection of persistent FVIII mRNA and protein expression in transduced cells. [0414] Factor 9 (Factor IX) Hemophilia B, also called factor IX (FIX) deficiency is a genetic disorder caused by missing or defective factor IX, a clotting protein. [0415] In some embodiments, the methods and systems described herein are used to correct factor IX deficiency by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing the FIX deficiency. Proposed validation is detection of persistent FiX mRNA and protein expression in transduced cells. [0416] Ornithine transcarbamylase deficiency (OTCD). Ornithine transcarbamylase deficiency is a rare genetic condition that causes ammonia to build up in the blood. The condition – more commonly called OTC deficiency – is more common in boys than girls and tends to be more severe when symptoms emerge shortly after birth. [0417] In some embodiments, the methods and systems described herein are used to correct OTC deficiency by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing the OTC deficiency or integrates a polynucleotide encoding a functional ornithine transcarbamylase enzyme. Proposed validation is detection of persistent OTC mRNA and protein expression in transduced cells. [0418] Phenylketonuria, also called PKU, is a rare inherited disorder that causes an amino acid called phenylalanine to build up in the body. PKU is caused by a change in the phenylalanine hydroxylase (PAH) gene. This gene helps create the enzyme needed to break down phenylalanine.
[0419] In some embodiments, the methods and systems described herein are used to correct PKU by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing the PKU deficiency or integrates a polynucleotide encoding a functional phenylalanine hydroxylase (PAH) gene. Proposed validation is detection of persistent PAH mRNA and protein expression in transduced cells. [0420] Homocystinuria (HCU). Homocystinuria is elevation of the amino acid, homocysteine (protein building block coming from our diet) in the urine or blood. Common causes of HCU include: problems with the enzyme cystathionine beta synthase (CBS), which converts homocysteine to the amino acid cystathionine (which then becomes cysteine) and needs the vitamin B6 (pyridoxine); and problems with converting homocysteine to the amino acid methionine. [0421] In some embodiments, the methods and systems described herein are used to correct HCU by site-specifically integrating in the genome a polynucleotide template that corrects the mutation causing the HCU or integrates a polynucleotide encoding a functional copy of a gene (e.g., CBS) able to reduce or prevent buildup of homocysteine in the urine. Proposed validation is detection of persistent CBS mRNA and protein expression in transduced cells. [0422] IgA Nephropathy (Berger’s disease). IgA nephropathy, also known as Berger's disease, is a kidney/autoimmune disease that occurs when an antibody called immunoglobulin A (IgA) builds up in the kidneys. [0423] In some embodiments, the methods and systems described herein are used to treat Berger’s disease by administering to a patient an iPSC-derived Natural Killer cell that includes a polynucleotide site-specifically integrated in the genome of the cell using the methods described herein. Upon administering the iPSC-NK cell to the patient, the iPSC-NK cell is capable of removing native cells (e.g., B cells) that are responsible, at least in part, for the symptoms of Berger’s disease. [0424] Anti-Neutrophil Cytoplasmic Antibody (ANCA) Vasculitis. ANCA vasculitis is an autoimmune disease affecting small blood vessels in the body. It is caused by autoantibodies called ANCAs, or Anti-Neutrophilic Cytoplasmic Autoantibodies. ANCAs target and attack a certain kind of white blood cells called neutrophils. [0425] In some embodiments, the methods and systems described herein are used to treat ANCA vasculitis by administering to a patient an iPSC-derived Natural Killer cell that includes a
polynucleotide site-specifically integrated in the genome of the cell using the methods described herein. Upon administering the iPSC-NK cell to the patient, the iPSC-NK cell is capable of removing native cells (e.g., B cells) that are responsible, at least in part, for the symptoms of ANCA vasculitis. [0426] Systemic Lupus Erythematosus (SLE) / Lupus Nephritis (LN). Lupus is an autoimmune—a disorder in which the body’s immune system attacks the body’s own cells and organs. [0427] In some embodiments, the methods and systems described herein are used to treat SLE/LN by administering to a patient an iPSC-derived Natural Killer cell that includes a polynucleotide site-specifically integrated in the genome of the cell using the methods described herein. Upon administering the iPSC-NK cell to the patient, the iPSC-NK cell is capable of removing native cells (e.g., B cells) that are responsible, at least in part, for the symptoms of SLE/LN. [0428] Membranous Nephropathy (MN). MN is a kidney disease that affects the filters (glomeruli) of the kidney and can cause protein in the urine, as well as decreased kidney function and swelling. It can sometimes be called membranous glomerulopathy as well (these terms can be used interchangeably and mean the same thing). [0429] In some embodiments, the methods and systems described herein are used to treat MN by administering to a patient an iPSC-derived Natural Killer cell that includes a polynucleotide site-specifically integrated in the genome of the cell using the methods described herein. Upon administering the iPSC-NK cell to the patient, the iPSC-NK cell is capable of removing native cells (e.g., B cells) that are responsible, at least in part, for the symptoms of MN. [0430] C3 glomerulonephritis (C3GN). C3 glomerulopathy is a group of related conditions that cause the kidneys to malfunction. The major features of C3 glomerulopathy include high levels of protein in the urine (proteinuria), blood in the urine (hematuria), reduced amounts of urine, low levels of protein in the blood, and swelling in many areas of the body. Affected individuals may have particularly low levels of a protein called complement component 3 (or C3) in the blood. [0431] In some embodiments, the methods and systems described herein are used to treat C3 glomerulopathy by administering to a patient an iPSC-derived Natural Killer cell that includes a polynucleotide site-specifically integrated in the genome of the cell using the methods described
herein. Upon administering the iPSC-NK cell to the patient, the iPSC-NK cell is capable of removing native cells (e.g., B cells) that are responsible, at least in part, for the symptoms of C3 glomerulopathy. 6.12. Pleiopluripotent Stem Cells [0432] In another embodiment, this disclosure features a pleiopluripotent cell comprising at least a first integration recognition site site-specifically incorporated into the pleiopluripotent cell genome. [0433] As used herein, the term “pleiopluripotent” refers to a pluripotent cell comprising at least a first integration recognition site. “Pluripotent” as used herein, refers to the ability of a cell to form all lineages of the body or the embryo proper. Pluripotency is a continuum of developmental potencies ranging from the incompletely or partially pluripotent cell (e.g., an epiblast stem cell or EpiSC), which is unable to give rise to a complete organism to the more primitive, more pluripotent cell, which is able to give rise to a complete organism (e.g., an embryonic stem cell). “Pluripotent” as used herein is intended to include cells that are totipotent, i.e., cells that have the ability to develop into an entire organism. [0434] In another aspect, this disclosure features a donor polynucleotide template (e.g., any of the donor polynucleotide templates described herein) comprised of one or more orthogonal integration recognition site integrated into the pleiopluripotent cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0435] In certain embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition site is incorporated into the pleiopluripotent cell genome at a safe harbor locus. [0436] In certain embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition sites is site-specifically incorporated within a locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. In some embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition sites is site-specifically incorporated into the genome at a locus required for surface expression of HLA class I proteins, HLA class II proteins, or a combination thereof. In some embodiments of any of the pleiopluripotent cells described herein, the locus is in a chromosomal region selected
from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. In some embodiments of any of the pleiopluripotent cells described herein, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, and RFXANK locus. In some embodiments of any of the pleiopluripotent cells described herein, the locus is the B2M locus. In some embodiments of any of the pleiopluripotent cells described herein, the locus is the CIITA locus. [0437] In some embodiments of any of the pleiopluripotent cells described herein, the pleiopluripotent cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. [0438] In some embodiments of any of the pleiopluripotent cells described herein, the PC-derived cell or population thereof includes at least a first integration recognition site-specifically incorporated into the genome. In some embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition sites is specific for a serine integrase. In some embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition sites is an attB or attP site. In some embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition sites is a modified attB or attP site. In some embodiments of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition site is specific for BxB1 or a modified BxB1. In some of any of the pleiopluripotent cells described herein, at least one of the at least first integration recognition sites is comprised of 38 or 46 nucleotides. [0439] In some embodiments of any of the pleiopluripotent cells described herein, the pleiopluripotent cell includes a first donor polynucleotide (e.g., any of the donor polynucleotide templates described herein, see, for example, Section 4.11.3) integrated into the pleiopluripotent stem cell genome at an at least first integration recognition site, where the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0440] In some embodiments of any of the pleiopluripotent cells described herein, the pleiopluripotent cell includes a second integration recognition site (e.g., any of the integration recognition sites described herein) site-specifically incorporated into the pleiopluripotent cell genome. [0441] In some embodiments of any of the pleiopluripotent cells described herein, the second integration recognition sites is site-specifically incorporated into a safe harbor locus.
[0442] In some embodiments of any of the pleiopluripotent cells described herein, the second integration recognition site is site-specifically incorporated within a second locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. Non-limiting examples of loci where disruption is capable of reducing allogeneic immune response to the PC-derived cell are as described in Section 4.11.1. For example, without limitation, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. In some embodiments, the locus where the first integration recognition site is incorporated into the genome and the second integration recognition site is incorporated into the genome are different. In some embodiments, the locus where the first integration recognition site is incorporated into the genome and the second integration recognition site is incorporated into the genome are the same. [0443] In some embodiments of any of the pleiopluripotent cells described herein, the PC-derived cell or population thereof includes a second integration recognition site-specifically incorporated into the genome. In some embodiments of any of the pleiopluripotent cells described herein, the second integration recognition sites is specific for a serine integrase. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is an attB or attP site. In some embodiments of any of the pleiopluripotent cells described herein, the second integration recognition sites is a modified attB or attP site. In some embodiments of any of the pleiopluripotent cells described herein, the second integration recognition site is specific for BxB1 or a modified BxB1. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is comprised of 38 or 46 nucleotides. [0444] In some embodiments of any of the pleiopluripotent cells described herein, the PC-derived cell or population thereof includes a second donor polynucleotide (e.g., any of the donor polynucleotide templates described herein, see, for example, Section 4.11.3) integrated into the pleiopluripotent stem cell genome at a second integration recognition site, where the second integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0445] In some embodiments of any of the pleiopluripotent cells described herein, the second donor polynucleotide template encodes one or more therapeutic agents. In some embodiments, the one or more therapeutic agents when expressed from the PC-derived cell or population thereof
treats, ameliorates, or prevents a disease or condition in a subject. Non-limiting examples of therapeutic agents are as described in Sections 4.11.5 and 4.11.7. In some embodiments of any of the pleiopluripotent cells described herein, the one or more therapeutic agents is a HLA class I proteins. In some embodiments of any of the PC-derived cell or populations thereof described herein, the one or more therapeutic agents is a HLA class I proteins. [0446] In some embodiments of any of the pleiopluripotent cells described herein, the second donor polynucleotide template comprises a pluripotent stem cell-specific promoter operably linked to at least one of the one or more therapeutic agents. In some embodiments of any of the pleiopluripotent cells described herein, the second donor polynucleotide template comprises a constitutive promoter operably linked to at least one of the one or more therapeutic agent. In some embodiments of any of the pleiopluripotent cells described herein, the second donor polynucleotide template comprises an inducible promoter operably linked to at least one therapeutic agent. [0447] In certain embodiments, the pleiopluripotent cells are derived from a mammal (e.g., a human, rhesus macaque (Macaca mulatta), bovine (Bos taurus), porcine (Sus scrofa), and mouse (Mus musculus)). In one embodiment, the pleiopluripotent cells are chimeric (i.e., a combination of iPSC derived from two or species). [0448] Non-limiting examples of pleiopluripotent cells include: induced pleiopluripotent cells (iPSC), embryonic stem cells (ESC), somatic cell nuclear transfer embryonic stem cells (ntES cells), epiblast stem cells (EpiSC) and parthenogenesis embryonic stem cell (pES cells). In certain embodiments, the pleiopluripotent cell is an embryonic stem cell or an induced pleiopluripotent cell. In one embodiment, pluripotent cells include cells capable of forming extraembryonic tissue (e.g., cell having totipotency). Pluripotency can be assessed using methods that include, but are not limited to: (i) pleiopluripotent cell morphology; (ii) the potential for unlimited self-renewal; (iii) expression of pleiopluripotent cell markers (e.g., OCT4, NANOG, SOX2, SSEA3/4, SSEA5, TRA1-60/81, TRAl-85, TRA2-54); (iv) teratoma formation consisting of the three somatic lineages; (v) formation of embryoid bodies consisting of cells from the three somatic lineages ; and (vi) ability to differentiate to all three somatic lineages (ectoderm, mesoderm and endoderm). [0449] In certain embodiments, the pleiopluripotent cell is an induced pluripotent stem cell (iPSC) derived from a non-pluripotent stem cell. In such cases, the non-pluripotent stem cell can be reprogrammed into an induced pleiopluripotent cell. Non-pluripotent stem cell can be reprogrammed into a induced pluripotent stem cell using exogenous genetic material (e.g.,
overexpression of transcription factors (e.g., Oct4, Sox2, Klf4, and c-Myc)), exogenous non- genetic material (e.g., small molecules (e.g., (valproic acid (VPA), CHIR99021, 616452, tranylcypromine (VC6T), and Forskolin (FSK (VC6TF))), or a combination thereof. Non-limiting examples of reprogramming a non-pluripotent stem cell into a pluripotent stem cell include methods as described in PCT Publications WO 2022/072883A1, and WO 2022/006399A1; U.S. Patent Nos.10,428,310B2; 9,499,797B2; and 8,802,438B2, each of which are herein incorporated by reference in their entireties. [0450] Also provided herein are cell banks comprising any of the pleiopluripotent cells described herein. 6.13. Pleiopluripotent (PC)-derived cell or a population thereof [0451] In another embodiments, this disclosure provides a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site (e.g., any of the integration recognition sites described herein) is incorporated site-specifically into the PC- derived cell genome. [0452] In another embodiment, this disclosure provides a pleiopluripotent (PC)-derived cell or a population thereof (i) the PC-derived cell is differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent stem cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. 6.13.1. PC-derived Hematopoietic Cell [0453] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a hematopoietic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site e.g., any of the integration recognition sites described herein) incorporated site-specifically into the PC-derived cell genome. [0454] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a hematopoietic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent stem cell genome at
an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0455] In some embodiments, the hematopoietic cell is selected from: hematopoietic stem and progenitor cells (HSC), pre-HSC, hematopoietic multipotent progenitor (MPP) cells, pre-T cell progenitor cells, pre-NK cell progenitor cells, T cell progenitor cells, NK cell progenitor cells, T cells, NK cells, NKT cells, or B cells. 6.13.2. PC-derived Neuronal Cell [0456] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a neuronal cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site (e.g., any of the integration recognition sites described herein) incorporated site-specifically into the PSC-derived cell genome. [0457] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a neuronal cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent stem cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0458] In some embodiments, the neuronal cell is selected from: a neural progenitor cell (NPC), a forebrain neuron, a dopaminergic neuron, a motor neuron, and a sensory neuron. 6.13.3. PC-derived Cardiac Cell [0459] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a cardiac cell differentiated from a pleiopluripotent cell; and (ii) the PC- derived cell comprises at least a first integration recognition site (e.g., any of the integration recognition sites described herein) incorporated site-specifically into the PSC-derived cell genome. [0460] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a cardiac cell differentiated from a pleiopluripotent cell; and (ii) the PC- derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent stem cell genome at
an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0461] In some embodiments, the cardiac cell is selected from: a cardiac mesodermal cell, a cardiac progenitor cell, and a cardiomyocyte. 6.13.4. PC-derived Pancreatic Cell [0462] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a pancreatic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises at least a first integration recognition site (e.g., any of the integration recognition sites described herein) incorporated site-specifically into the PC-derived cell genome. [0463] In some embodiments, a pleiopluripotent (PC)-derived cell or a population thereof where (i) the PC-derived cell is a pancreatic cell differentiated from a pleiopluripotent cell; and (ii) the PC-derived cell comprises a first donor polynucleotide template, comprised of one or more orthogonal integration recognition site, integrated into the pleiopluripotent stem cell genome at an at least first integration recognition site, wherein the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0464] In some embodiments, the pancreatic cell is selected from a pancreatic progenitor cell, pancreatic endoderm, an endocrine pancreatic cell, an exocrine pancreatic cell, a islet progenitor, and a beta cell. 6.13.5. Features of PC-derived cell or Populations Thereof [0465] In some embodiments of any of the PC-derived cell or populations thereof described herein, the PC-derived cell further comprises two integration recognition sites, three integration recognition sites, four integration recognition sites, five integration recognition sites, six integration recognition sites, seven integration recognition sites, eight integration recognition sites, nine integration recognition sites, or ten or more integration recognition sites. [0466] In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition sites is incorporated into the pleiopluripotent cell genome at a safe harbor locus. [0467] In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition sites is site-specifically incorporated within a locus, disruption of which is capable of reducing allogeneic immune response to the PC-
derived cell. Non-limiting examples of loci where disruption is capable of reducing allogeneic immune response to the PC-derived cell are as described in Section 4.11.1. For example, without limitation, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA- C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. [0468] In some embodiments of any of the PC-derived cell or populations thereof described herein, the PC-derived cell or population thereof includes at least a first integration recognition site-specifically incorporated into the genome. In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition sites is specific for a serine integrase. In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition sites is an attB or attP site. In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition sites is a modified attB or attP site. In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition site is specific for BxB1 or a modified BxB1. In some embodiments of any of the PC-derived cell or populations thereof described herein, at least one of the at least first integration recognition sites is comprised of 38 or 46 nucleotides. [0469] In some embodiments of any of the PC-derived cell or populations thereof described herein, the PC-derived cell or population thereof includes a first donor polynucleotide (e.g., any of the donor polynucleotide templates described herein, see, for example, Section 4.11.3) integrated into the pleiopluripotent stem cell genome at an at least first integration recognition site, where the at least first integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. 6.13.6. Second integration recognition site [0470] In some embodiments of any of the PC-derived cell or populations thereof described herein, the PC-derived cell or population thereof includes a second integration recognition site (e.g., any of the integration recognition sites described herein) site-specifically incorporated into the pleiopluripotent cell genome.
[0471] In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is site-specifically incorporated into a safe harbor locus. [0472] In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition site is site-specifically incorporated within a second locus, disruption of which is capable of reducing allogeneic immune response to the pleiopluripotent stem cell or a cell matured from the pleiopluripotent stem cell. Non-limiting examples of loci where disruption is capable of reducing allogeneic immune response to the PC- derived cell are as described in Section 4.11.1. For example, without limitation, the locus is selected from B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. In some embodiments, the locus is the B2M locus. In some embodiments, the locus is the CIITA locus. In some embodiments, the locus where the first integration recognition site is incorporated into the genome and the second integration recognition site is incorporated into the genome are different. In some embodiments, the locus where the first integration recognition site is incorporated into the genome and the second integration recognition site is incorporated into the genome are the same. [0473] In some embodiments of any of the PC-derived cell or populations thereof described herein, the PC-derived cell or population thereof includes a second integration recognition site- specifically incorporated into the genome. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is specific for a serine integrase. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is an attB or attP site. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is a modified attB or attP site. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition site is specific for BxB1 or a modified BxB1. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second integration recognition sites is comprised of 38 or 46 nucleotides. [0474] In some embodiments of any of the PC-derived cell or populations thereof described herein, the PC-derived cell or population thereof includes a second donor polynucleotide (e.g., any of the donor polynucleotide templates described herein, see, for example, Section 4.11.3) integrated into the pleiopluripotent stem cell genome at a second integration recognition site,
where the second integration recognition site is site-specifically incorporated into the pleiopluripotent cell genome. [0475] In some embodiments of any of the PC-derived cell or populations thereof described herein, the second donor polynucleotide template encodes one or more therapeutic agents. In some embodiments, the one or more therapeutic agents when expressed from the PC-derived cell or population thereof treats, ameliorates, or prevents a disease or condition in a subject. Non-limiting examples of therapeutic agents are as described in Sections 4.11.5and 4.11.7. In some embodiments of any of the PC-derived cell or populations thereof described herein, the one or more therapeutic agents is a HLA class I proteins. In some embodiments of any of the PC-derived cell or populations thereof described herein, the one or more therapeutic agents is a HLA class I proteins. [0476] In some embodiments of any of the PC-derived cell or populations thereof described herein, the second donor polynucleotide template comprises a pluripotent stem cell-specific promoter operably linked to at least one of the one or more therapeutic agents. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second donor polynucleotide template comprises a constitutive promoter operably linked to at least one of the one or more therapeutic agent. In some embodiments of any of the PC-derived cell or populations thereof described herein, the second donor polynucleotide template comprises an inducible promoter operably linked to at least one therapeutic agent. 6.14. Kits and Cell-based Compositions [0477] This disclosure also provides certain components or embodiments of cell-based products (e.g., genetically modified pleiopluripotent cells or cells-derived therefrom, such as a hematopoietic cell, a neuronal cell, a cardiac cell, or a beta cell) or pharmaceutical compositions thereof, can be provided in a kit. For example, any of the cell-based products described herein (e.g., any of the genetically modified pleiopluripotent cells or cells-derived therefrom, such as a hematopoietic cell, a neuronal cell, a cardiac cell, or a pancreatic cell) can be provided frozen and packaged as a kit, alone or along with separate containers of any of the other agents from the pre- conditioning or post-conditioning steps, and optional instructions for use. [0478] In some embodiments, the cell-based products (e.g., genetically modified pleiopluripotent cells or cells-derived therefrom, such as a hematopoietic cell, a neuronal cell, a cardiac cell, or a beta cell) may be frozen (cryopreserved) before administration into a subject. In some embodiments, cell-based products (e.g., genetically modified pleiopluripotent cells or cells-
derived therefrom, such as a hematopoietic cell, a neuronal cell, a cardiac cell, or a beta cell) may be frozen by suspending the cells in media containing at least 10% (e.g., at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, or at least 50%) human-derived serum and/or plasma, and lowering the temperature of the suspension to at least -80° C, thereby freezing the cell-based products. In some embodiments, the freezing media is approximately 30% human- derived serum and/or plasma and approximately 10% of an agent that prevents ice crystal formation during freezing, e.g., DMSO. In a further embodiment, the cell-based product (e.g., genetically modified pleiopluripotent cells or cells-derived therefrom, such as a hematopoietic cell, a neuronal cell, a cardiac cell, or a beta cell) freezing media suspension is maintained at -80°C for at least 24 hours and then transferred to liquid nitrogen for the duration of the storage. In a further embodiment, the frozen cell-based product (e.g., genetically modified pleiopluripotent cells or cells-derived therefrom, such as a hematopoietic cell, a neuronal cell, a cardiac cell, or a beta cell) suspension is thawed at a temperature in the range of 34°C to 41°C. [0479] In some embodiments, the genetically modified pleiopluripotent cells are selected, isolated, or a combination thereof, prior to being banked (e.g., cryopreserved). In some embodiments, the genetically modified pleiopluripotent cells are selected in bulk before being banked (e.g., cryopreserved). In some embodiments, the genetically modified pleiopluripotent cells are isolated prior to being banked (e.g., cryopreserved). In such cases, the genetically modified pleiopluripotent cells are isolated and expanded prior to being banked (e.g., cryopreserved). [0480] In some embodiments, the genetically modified pluripotent stem cells are banked (e.g., cryopreserved) following incorporation of one or more integration recognition sites (e.g., any of the integration recognition sites described herein) but prior to integration of a donor polynucleotide template (e.g., any of the donor polynucleotide templates described herein). In such cases, the genetically modified pluripotent stem cells are thawed (and optionally allowed to recover) prior to integrating a donor polynucleotide template (e.g., any of the donor polynucleotide templates described herein) into the genome of the pluripotent stem cell. [0481] In some embodiments, the genetically modified pluripotent stem cells are banked (e.g., cryopreserved) following incorporation of one or more integration recognition sites (“beacons”) (e.g., any of the integration recognition sites described herein) and integration of a donor polynucleotide template (e.g., any of the donor polynucleotide templates described herein). In such cases, the genetically modified pluripotent stem cells can be thawed (and optionally allowed to recover) prior to integrating a second donor polynucleotide template (e.g., any of the donor polynucleotide templates described herein) into the genome of the pluripotent stem cell. In other
cases, the genetically modified pluripotent stem cells can be thawed (and optionally allowed to recover) and used for downstream applications (e.g., differentiation to a hematopoietic stem cell, a neuronal cell, a cardiac cell, or a beta cell and use as a source for cell therapy). [0482] In some embodiments, the cells (e.g., genetically modified pluripotent stem cells) are frozen, which can be referred to as cryopreservation. The cells (e.g., genetically modified pluripotent stem cells) can, for example, be frozen using CryoStor CS5 (freeze media), Cryostor CS10 (freeze media), or another freeze media. However, this is a non-limiting example of freezing media and other freezing media can be used. The cells (e.g., genetically modified pluripotent stem cells) can be initially chilled 4°C. Then the cells (e.g., genetically modified pluripotent stem cells) can be further cooled to about -20°C. The cells (e.g., genetically modified pluripotent stem cells) can be centrifuged or resuspended in additional freeze media and then cooled to -90°C in a stepwise manner. The cells (e.g., genetically modified pluripotent stem cells) can then be stored in liquid nitrogen. In some embodiments, the cells (e.g., genetically modified pluripotent stem cells) are frozen in a cryobag. [0483] In some embodiments, the composition may comprise a pharmaceutically acceptable excipient, a pharmaceutically acceptable salt, diluents, carriers, vehicles and such other inactive agents well known to the skilled artisan. Vehicles and excipients commonly employed in pharmaceutical preparations include, for example, talc, gum Arabic, lactose, starch, magnesium stearate, cocoa butter, aqueous or non-aqueous solvents, oils, paraffin derivatives, glycols, etc. Solutions can be prepared using water or physiologically compatible organic solvents such as ethanol, 1,2-propylene glycol, polyglycols, dimethylsulfoxide, fatty alcohols, triglycerides, partial esters of glycerine and the like. Compositions may be prepared using conventional techniques that may include sterile isotonic saline, water, 1,3-butanediol, ethanol, 1,2-propylene glycol, polyglycols mixed with water, Ringer's solution, etc. In one aspect, a coloring agent is added to facilitate in locating and properly placing the composition to the intended treatment site. [0484] Compositions may include a preservative and/or a stabilizer. Non-limiting examples of preservatives include methyl-, ethyl-, propyl-parabens, sodium benzoate, benzoic acid, sorbic acid, potassium sorbate, propionic acid, benzalkonium chloride, benzyl alcohol, thimerosal, phenylmercurate salts, chlorhexidine, phenol, 3-cresol, quaternary ammonium compounds (QACs), chlorbutanol, 2-ethoxyethanol, and imidurea. [0485] To control tonicity, the composition can comprise a physiological salt, such as a sodium salt. Sodium chloride (NaCl) is preferred, which may be present at between 1 and 20 mg/ml. Other
salts that may be present include potassium chloride, potassium dihydrogen phosphate, disodium phosphate dehydrate, magnesium chloride and calcium chloride. [0486] Compositions may include one or more buffers. Typical buffers include: a phosphate buffer; a Tris buffer; a borate buffer; a succinate buffer; a histidine buffer; or a citrate buffer. Buffers will typically be included at a concentration in the 5-20 mM range. The pH of a composition will generally be between 5 and 8, and more typically between 6 and 8 e.g. between 6.5 and 7.5, or between 7.0 and 7.8. [0487] In some embodiments, the composition may include a cryoprotectant agent. Non-limiting examples of cryoprotectant agents include a glycol (e.g., ethylene glycol, propylene glycol, and glycerol), dimethyl sulfoxide (DMSO), formamide, sucrose, trehalose, dextrose, and any combinations thereof. [0488] Some embodiments are also directed to any of the aforementioned compositions in a kit. In some embodiments, the kit may comprise ampoules, disposable syringes, capsules, vials, tubes, or the like. In some embodiments, the kit may comprise a single dose container or multiple dose containers comprising the topical formulation of embodiments herein. In some embodiments, each dose container may contain one or more unit doses. In some embodiments, the kit may include an applicator. In some embodiments, the kits include all components needed for the stages of conditioning/treatment. In some embodiments, the cellular compositions may have preservatives or be preservative-free (for example, in a single-use container). In some embodiments, the cell-based products may be prepared and frozen at a desired stage, suitable for shipping to a hospital or treatment center. [0489] Also provided herein are methods for freezing, thawing, and expanding any of the pluripotent stem cells described herein. 6.15. Pharmaceutical Compositions [0490] This disclosure provides pharmaceutical compositions comprising the pluripotent stem cell or hematopoietic cell, cardiac cell or neuronal cell derived from the pluripotent stem cell, wherein the pharmaceutical compositions further comprise a pharmaceutically acceptable medium. In one embodiment, the pharmaceutical composition comprises the pluripotent cell derived hematopoietic cells made by the methods and composition disclosed herein. In one embodiment, the pharmaceutical composition comprises the pluripotent cell derived cardiac cells made by the methods and composition disclosed herein. In one embodiment, the pharmaceutical composition
comprises the pluripotent cell derived neuronal cells made by the methods and composition disclosed herein. 6.16. Directed Differentiation of Pleiopluripotent Cells [0491] In certain embodiments, the method further includes directing differentiation of the modified pluripotent stem cell to a hematopoietic cell. Non-limiting examples of a hematopoietic cell include: hematopoietic stem and progenitor cells (HSC), pre-HSC, hematopoietic multipotent progenitor (MPP) cells, pre-T cell progenitor cells, pre-NK cell progenitor cells, T cell progenitor cells, NK cell progenitor cells, T cells, NK cells, NKT cells, B cells, platelets, erythrocytes, erythrocyte progenitors, megakaryocytes, and megakaryocyte precursors. Non-limiting methods of directing differentiation of the modified pluripotent stem cell to a hematopoietic cell include the methods described in U.S. Patent Pub. Nos. 2019/0119643A1; 2019/0177695A1, 2020/0199535A1, U.S. Patent Nos.10,858,628; 11,162,075; 10,947,505; and 11,162,076, each of which are herein incorporated by reference in their entireties. [0492] In certain embodiments, the method further includes directing differentiation of the modified pluripotent stem cell to a neuronal cell. Non-limiting examples of neuronal cells include: a neural progenitor cell (NPC), a forebrain neuron, a dopaminergic neuron, a motor neuron, and a sensory neuron. Non-limiting methods of directing differentiation of the modified pluripotent stem cell to a neuronal cell include the methods described in the PCT Publication Nos. WO2022/134031A1; WO2022/136306A1; WO2022/093375A1; WO2022/014681A1; and WO2022005023A1; U.S. Patent Nos. 11,007,232; 10,519,421; and 10,487,311; and U.S. Patent Pubs.2021/0244768A1, each of which are herein incorporated by reference in their entireties. [0493] In certain embodiments, the method further comprises directing differentiation of the modified pluripotent stem cell to a cardiac cell. Non-limiting examples of a cardiac cell include: a cardiac mesodermal cell, a cardiac progenitor cell, and a cardiomyocyte. Non-limiting methods of directing differentiation of the modified pluripotent stem cell to a cardiomyocyte include the methods described in PCT Publication Nos. WO2020/247957; WO2021/187601A1; WO2021/172542A1; and WO2020/264308A1; and U.S. Patent Nos. 11,352,604; 10,973,876; 10,443,044; and 9,587,220; and U.S. Patent Pubs.2021/0363487A1, and 2020/0140819A1, each of which are herein incorporated by reference in their entireties. [0494] In certain embodiments, the method further comprises directing differentiation of the modified pluripotent stem cell to a pancreatic cell. Non-limiting examples of a pancreatic cell include: a pancreatic progenitor cell, pancreatic endoderm, an endocrine pancreatic cell, an
exocrine pancreatic cell, a islet progenitor, and a beta cell. Non-limiting methods of directing differentiation of the modified pluripotent stem cell to a beta cell include the methods described in PCT Publication Nos. WO2020/033879A1; WO2021/030424A1; and WO2020/264072A1, U.S. Patent Nos. 10,376,545; and 9,650,610; U.S. Patent Publication No. US20210198632A1, each of which are herein incorporated by reference in their entireties. 6.17. Method of Using the Pleiopluripotent Cell (PC) or PC-derived Cell [0495] This disclosure also provides a method of using a pleiopluripotent cell having at least a first integration recognition site site-specifically incorporated into the pleiopluripotent cell genome, the method comprising: integrating a first donor polynucleotide template into the pleiopluripotent cell genome by introducing into the pleiopluripotent cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more orthogonal integration recognition sites, and (ii) an integrase, whereby the donor polynucleotide is integrated into the pleiopluripotent stem cell at the at least one incorporated genomic integration recognition sites by the integrase. [0496] In some embodiments, the method of using pleiopluripotent cells also includes selecting the pleiopluripotent stem cells having the first donor polynucleotide template site-specifically integrated into the genome. In some embodiments, the method of using pleiopluripotent cells also includes expanding the pleiopluripotent cells in a de-differentiated state. [0497] In some embodiments, the method of using pleiopluripotent cells also includes cryopreserving the pleiopluripotent cells following incorporation of the at least first integration recognition site. In some embodiments, the method of using pleiopluripotent cells also includes cryopreserving the pleiopluripotent cells following integrating the donor polynucleotide template at the at least one incorporated genomic recognition site. [0498] In some embodiments, the method of using the pleiopluripotent cells also includes directing differentiation of the modified pleiopluripotent cell to a hematopoietic cell. Non- limiting examples of hematopoietic cells include: hematopoietic stem and progenitor cells (HSC), pre-HSC, hematopoietic multipotent progenitor (MPP) cells, pre-T cell progenitor cells, pre-NK cell progenitor cells, T cell progenitor cells, NK cell progenitor cells, T cells, NK cells, NKT cells, or B cells. [0499] In some embodiments, the method of using the pleiopluripotent cells also includes directing differentiation of the modified pleiopluripotent cell to a neuronal cell. Non-limiting
examples of a neuronal cell is selected from: a neural progenitor cell (NPC), a forebrain neuron, a dopaminergic neuron, a motor neuron, and a sensory neuron. [0500] In some embodiments, the method of using the pleiopluripotent cells also includes directing differentiation of the modified pleiopluripotent cell to a cardiac cell. Non-limiting examples of cardiac cells include a cardiac mesodermal cell, a cardiac progenitor cell, and a cardiomyocyte. [0501] In some embodiments, the method of using the pleiopluripotent cells also includes directing differentiation of the modified pleiopluripotent cell to a pancreatic cell. Non-limiting examples of pancreatic cells include pancreatic progenitor cell, pancreatic endoderm, an endocrine pancreatic cell, an exocrine pancreatic cell, an islet progenitor, and a beta cell. [0502] In some embodiments, the method of using the pleiopluripotent cells also includes administering the PC-derived cells or a population thereof to a subject (patient) in need thereof. 6.18. Programmable Gene Insertion for Research Purposes [0503] In another aspect, the methods and compositions described herein can be used to generate cell lines for research purposes or applications that are intended for research purposes only. For example, the methods (see, e.g., Section 6.11), cells (e.g., Section 6.12 and 6.13), kits (see, e.g., Section 6.14), and compositions (see, e.g., Section 6.15) can be used for research purposes or applications that are intended for research purposes only. In one embodiment, the methods (see, e.g., Section 6.11), cells (e.g., Section 6.12 and 6.13), kits (see, e.g., Section 6.14), and compositions (see, e.g., Section 6.15) can be used for screening purposes, for example, screening therapeutic molecules (e.g., compounds, small molecules, and large molecules). 6.19. Methods of Treatment [0504] In another aspect, methods of treatment are presented. In some embodiments, the subject has a disease, condition, and/or an injury that can be treated, ameliorated, and/or improved by a cell therapy. Some embodiments contemplate that a subject in need of cell therapy is a subject with an injury, disease, or condition, whereby a cell therapy, for example, a therapy in which a cellular material is administered to the subject, can treat, ameliorate, improve, and/or reduce the severity of at least one symptom associated with the injury, disease, or condition. [0505] Certain embodiments contemplate that a subject in need of cell therapy, includes, but is not limited to, a candidate for bone marrow or stem cell transplantation, a subject who has received chemotherapy or irradiation therapy, a subject who has or is at risk of having a hyperproliferative
disorder or a cancer, (e.g., a hyperproliferative disorder) or a cancer of hematopoietic system, a subject having or at risk of developing a tumor (e.g., a solid tumor), a subject who has or is at risk of having a viral infection or a disease associated with a viral infection. [0506] This disclosure also features a method of treating or ameliorating or preventing a disease or condition in a subject, comprising administering a therapeutically effective amount of any of the PC-derived cell or population thereof, compositions, or pharmaceutical composition described herein. [0507] In some embodiments, the method includes treating or ameliorating or preventing cancer, where the subject has, or is suspected of having, cancer. [0508] In some embodiments, the method includes treating or ameliorating or preventing a cardiac condition, where the subject has or is suspected of having, a cardiac condition. In such cases, the cardiac condition is muscular and/or the condition is muscle degeneration or muscle injury. [0509] In some embodiments, the method includes treating or ameliorating or preventing a neuronal-associated disease, wherein the subject has, or is suspected of having, a neuronal- associated disease. In such cases, the disease is a neuronal-associated disease and/or the condition is neuron degeneration. [0510] In some embodiments, the method includes treating or ameliorating or preventing a pancreatic-associated disease, wherein the subject has, or is suspected of having, a pancreatic- associated disease. [0511] In some embodiments, the method of treating further includes administering to the subject, having previously been administered any of pluripotent stem cells described herein, one or more exogenous molecules to control activity of the one or more inducible suicide genes. In a non- limiting example, the method of treating also includes, following administration of any of the PC- derived cells or populations thereof as described herein, administering AP20187 (or an analog thereof), AP21967, ganciclovir, or a combination thereof. [0512] In some embodiments, the method of cell delivery used here occurs using electroporation. [0513] In some embodiments, the method of cell delivery used here occurs using a recombinant adenovirus, helper dependent adenovirus, AAV, lentivirus, HSV, anellovirus, retrovirus, Doggybone DNA, minicircle, plasmid, miniDNA, nanoplasmid, mRNA, RNP, or lipid
nanoparticle. Delivery of the nucleic acid construct can also be by fusosome or exosome, (See, e.g., WO2019222403 which is incorporated by reference herein). Delivery of nucleic acid construct can also be by VesiCas (See, e.g., US20210261957A1 which is incorporated by reference herein). [0514] Methods of non-viral delivery include lipofection, nucleofection, microinjection, biolistics, virosomes, liposomes, immunoliposomes, polycation or lipid:nucleic acid conjugates, naked DNA, artificial virions, and agent-enhanced uptake of DNA. Lipofection is described in e.g., U.S. Pat. Nos. 5,049,386, 4,946,787; and 4,897,355) and lipofection reagents are sold commercially (e.g., Transfectam™ and Lipofectin™). Cationic and neutral lipids that are suitable for efficient receptor-recognition lipofection of polynucleotides include those of Felgner, WO 91/17424; WO 91/16024. Delivery can be to cells (e.g. in vitro or ex vivo administration) or target tissues (e.g. in vivo administration). 6.19.1. Viral Vector Delivery into the Pluripotent Stem Cell Genome [0515] In certain aspects the invention involves vectors, e.g. for delivering or introducing in a cell, but also for propagating these components (e.g. in prokaryotic cells). A used herein, a "vector" is a tool that allows or facilitates the transfer of an entity from one environment to another. It is a replicon, such as a plasmid, phage, or cosmid, into which another DNA segment may be inserted so as to bring about the replication of the inserted segment. Generally, a vector is capable of replication when associated with the proper control elements. In general, the term "vector" refers to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. Vectors include, but are not limited to, nucleic acid molecules that are single-stranded, double- stranded, or partially double-stranded; nucleic acid molecules that comprise one or more free ends, no free ends (e.g. circular); nucleic acid molecules that comprise DNA, RNA, or both; and other varieties of polynucleotides known in the art. One type of vector is a "plasmid," which refers to a circular double stranded DNA loop into which additional DNA segments can be inserted, such as by standard molecular cloning techniques. Another type of vector is a viral vector, wherein virally- derived DNA or RNA sequences are present in the vector for packaging into a virus (e.g. retroviruses, replication defective retroviruses, adenoviruses, replication defective adenoviruses, and adeno-associated viruses (AAVs)). Viral vectors also include polynucleotides carried by a virus for transfection into a host cell. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g. bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and
thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively-linked. Such vectors are referred to herein as "expression vectors." Vectors for and that result in expression in a eukaryotic cell can be referred to herein as "eukaryotic expression vectors." Common expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. [0516] Recombinant expression vectors can comprise a nucleic acid of the invention in a form suitable for expression of the nucleic acid in a host cell, which means that the recombinant expression vectors include one or more regulatory elements, which may be selected on the basis of the host cells to be used for expression, that is operatively-linked to the nucleic acid sequence to be expressed. Within a recombinant expression vector, "operably linked" is intended to mean that the nucleotide sequence of interest is linked to the regulatory element(s) in a manner that allows for expression of the nucleotide sequence (e.g. in an in vitro transcription/translation system or in a host cell when the vector is introduced into the host cell). With regards to recombination and cloning methods, mention is made of U.S. patent application Ser. No.10/815,730, published Sep.2, 2004 as US 2004-0171156 A1, the contents of which are herein incorporated by reference in their entirety. [0517] Vector delivery, e.g., plasmid, viral delivery: The CRISPR enzyme, for instance a Type V protein such as C2c1 or C2c3, and/or any of the present RNAs, for instance a guide RNA, can be delivered using any suitable vector, e.g., plasmid or viral vectors, such as adeno associated virus (AAV), lentivirus, adenovirus or other viral vector types, or combinations thereof. Effector proteins and one or more guide RNAs can be packaged into one or more vectors, e.g., plasmid or viral vectors. [0518] The promoter used to drive nucleic acid-targeting effector protein coding nucleic acid molecule expression can include: AAV ITR can serve as a promoter: this is advantageous for eliminating the need for an additional promoter element (which can take up space in the vector). The additional space freed up can be used to drive the expression of additional elements (gRNA, etc.). Also, ITR activity is relatively weaker, so can be used to reduce potential toxicity due to over expression of nucleic acid-targeting effector protein. For ubiquitous expression, can use promoters: CMV, CAG, CBh, PGK, SV40, Ferritin heavy or light chains, etc. For brain or other CNS expression, can use promoters: Synapsin I for all neurons, CaMKII alpha for excitatory neurons, GAD67 or GAD65 or VGAT for GABAergic neurons, etc. For liver expression, can use Albumin promoter. For lung expression, can use SP-B. For endothelial cells, can use ICAM. For hematopoietic cells can use IFNbeta or CD45. For Osteoblasts can use OG-2.
[0519] The promoter used to drive guide RNA can include: Pol III promoters such as U6 or H1 Use of Pol II promoter and intronic cassettes to express guide RNA Adeno Associated Virus (AAV) [0520] Nucleic acid-targeting effector protein and one or more guide RNA can be delivered using adeno associated virus (AAV), lentivirus, adenovirus or other plasmid or viral vector types, in particular, using formulations and doses from, for example, U.S. Pat. No.8,454,972 (formulations, doses for adenovirus), U.S. Pat. No.8,404,658 (formulations, doses for AAV) and U.S. Pat. No. 5,846,946 (formulations, doses for DNA plasmids) and from clinical trials and publications regarding the clinical trials involving lentivirus, AAV and adenovirus. For examples, for AAV, the route of administration, formulation and dose can be as in U.S. Pat. No. 8,454,972 and as in clinical trials involving AAV. For Adenovirus, the route of administration, formulation and dose can be as in U.S. Pat. No. 8,404,658 and as in clinical trials involving adenovirus. For plasmid delivery, the route of administration, formulation and dose can be as in U.S. Pat. No. 5,846,946 and as in clinical studies involving plasmids. Doses may be based on or extrapolated to an average 70 kg individual (e.g., a male adult human), and can be adjusted for patients, subjects, mammals of different weight and species. Frequency of administration is within the ambit of the medical or veterinary practitioner (e.g., physician, veterinarian), depending on usual factors including the age, sex, general health, other conditions of the patient or subject and the particular condition or symptoms being addressed. The viral vectors can be injected into the tissue of interest. For cell- type specific genome modification, the expression of nucleic acid-targeting effector can be driven by a cell-type specific promoter. For example, liver-specific expression might use the Albumin promoter and neuron-specific expression (e.g., for targeting CNS disorders) might use the Synapsin I promoter. [0521] Another useful method to deliver proteins, enzymes, and guides to a pluripotent stem cell comprises transfection of messenger RNA (mRNA). Examples of mRNA delivery methods and compositions that may be utilized in the present disclosure including, for example, PCT/US2014/028330, US8822663B2, NZ700688A, ES2740248T3, EP2755693A4, EP2755986A4, WO2014152940A1, EP3450553B1, BR112016030852A2, and EP3362461A1. Expression of CRISPR systems in particular is described by WO2020014577. Each of these publications are incorporated herein by reference in their entireties. Additional disclosure hereby incorporated by reference can be found in Kowalski et al., “Delivering the Messenger: Advances in Technologies for Therapeutic mRNA Delivery,” Mol Therap., 2019; 27(4): 710-728.
[0522] In some embodiments, one or more vectors described herein are used to produce a non- human transgenic animal or transgenic plant. In some embodiments, the transgenic animal is a mammal, such as a mouse, rat, or rabbit. In certain embodiments, the organism or subject is a plant. In certain embodiments, the organism or subject or plant is algae. Methods for producing transgenic plants and animals are known in the art, and generally begin with a method of cell transfection, such as described herein. [0523] In some embodiments, the method comprises sampling a cell or population of cells from a human or non-human animal or plant (including micro-algae) and modifying the cell or cells. Culturing may occur at any stage ex vivo. The cell or cells may even be re-introduced into the non-human animal or plant (including micro-algae). [0524] Examples of target polynucleotides include a sequence associated with a signaling biochemical pathway, e.g., a signaling biochemical pathway-associated gene or polynucleotide. Examples of target polynucleotides include a disease associated gene or polynucleotide. A "disease-associated" gene or polynucleotide refers to any gene or polynucleotide which is yielding transcription or translation products at an abnormal level or in an abnormal form in cells derived from a disease-affected tissues compared with tissues or cells of a non-disease control. It may be a gene that becomes expressed at an abnormally high level; it may be a gene that becomes expressed at an abnormally low level, where the altered expression correlates with the occurrence and/or progression of the disease. A disease-associated gene also refers to a gene possessing mutation(s) or genetic variation that is directly responsible or is in linkage disequilibrium with a gene(s) that is responsible for the etiology of a disease. The transcribed or translated products may be known or unknown and may be at a normal or abnormal level. [0525] In some embodiments, the genetically modified cell are non-dividing cells (e.g., where cell growth has been arrested) prior to being contacted with the gene editing reagents (e.g., gene editor protein or a polynucleotide encoding a gene editor protein, one or more guide RNA, and optionally a nicking gRNA). In some embodiments, the genetically modified cells are terminally differentiated, non-dividing cells prior to being contacted with the gene editing reagents (e.g., gene editor protein or a polynucleotide encoding a gene editor protein, one or more guide RNA, and optionally a nicking gRNA). In some embodiments, the genetically modified cells are dividing cells.
7. ADDITIONAL EMBODIMENTS [0526] Embodiment 1. A method of editing a pluripotent stem cell, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of incorporating the one or more integration target recognition sites into the genome; and (ii) two guide RNAs, wherein each of the two guide RNA encodes all or part of an integrase target recognition site. [0527] Embodiment 2. A method of editing a pluripotent stem cell, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of incorporating the one or more integration target recognition sites into the genome; and (ii) two guide RNA complexes, wherein each of the two guide RNA complexes is comprised of at least one polynucleotide that encodes all or part of an integrase target recognition site. [0528] Embodiment 3. A method of editing a pluripotent stem cell, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of incorporating the one or more integration target recognition sites into the genome; (ii) one or more guide RNA, wherein the one or more guide RNA encodes an integrase target recognition site; and (iii) optionally, a nicking gRNA. [0529] Embodiment 4. A method of editing a pluripotent stem cell, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of polynucleotide genomic integration; (ii) one or more guide RNA complex, wherein the one or more guide RNA complex is comprised of at least one polynucleotide that encodes an integrase target recognition site; and (iii) optionally, a nicking gRNA. [0530] Embodiment 5. The method of any one of embodiments 1-4, further comprising: b) integrating a donor polynucleotide template into the pluripotent stem cell genome at the one or more incorporated target recognition sites by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more integration target recognition sites, wherein the donor polynucleotide is integrated into the pluripotent stem cell at
the one or more incorporated genomic integration target recognition sites by an integrase; thereby producing a genetically modified pluripotent stem cell. [0531] Embodiment 6. A method of editing a pluripotent stem cell, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of incorporating the one or more integration target recognition sites into the genome; and (ii) two guide RNAs, wherein each of the two guide RNA encodes all or a portion of an integrase target recognition site; and (b) integrating a donor polynucleotide template into the pluripotent stem cell genome at the one or more incorporated target recognition sites by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more integration target recognition sites, wherein the donor polynucleotide is integrated into the pluripotent stem cell at the incorporated genomic integration target recognition site by an integrase; thereby producing a genetically modified pluripotent stem cell. [0532] Embodiment 7. A method of editing a pluripotent stem cell genome, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of polynucleotide genomic integration; and (ii) two guide RNA complexes, wherein each of the two guide RNA complexes is comprised of at least one polynucleotide that encodes all or part of an integrase target recognition site; and (b) integrating a donor polynucleotide template into the pluripotent stem cell genome at the one or more incorporated target recognition sites by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of one of more integration target recognition sites, wherein the donor polynucleotide is integrated into the pluripotent stem cell at the one or more incorporated genomic integration target recognition sites by an integrase; thereby producing a genetically modified pluripotent stem cell. [0533] Embodiment 8. A method of editing a pluripotent stem cell, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or a polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of incorporating the one or more integration target recognition sites into the genome; (ii) one or more guide RNA, wherein the one or more guide RNA encodes an integrase target recognition site; and (iii) optionally, a nicking gRNA; and (b) integrating a donor polynucleotide template into the pluripotent stem cell genome at the one or
more incorporated target recognition sites by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more integration target recognition sites, wherein the donor polynucleotide is integrated into the pluripotent stem cell at the incorporated genomic integration target recognition site by an integrase; thereby producing a genetically modified pluripotent stem cell. [0534] Embodiment 9. A method of editing a pluripotent stem cell genome, the method comprising: (a) incorporating one or more integration target recognition sites into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of polynucleotide genomic integration; (ii) one or more guide RNA complex, wherein the one or more guide RNA complex is comprised of at least one polynucleotide that encodes an integrase target recognition site; and (iii) optionally, a nicking gRNA; and (b) integrating a donor polynucleotide template into the pluripotent stem cell genome at the one or more incorporated target recognition sites by delivering into the cell: (i) the donor polynucleotide template, wherein the donor polynucleotide template is comprised of one of more integration target recognition sites, wherein the donor polynucleotide is integrated into the pluripotent stem cell at the one or more incorporated genomic integration target recognition sites by an integrase; thereby producing a genetically modified pluripotent stem cell. [0535] Embodiment 10. The method of any one of embodiments 6-9, wherein steps (a) and (b) are performed concurrently. [0536] Embodiment 11. The method of any one of embodiments 1-10, wherein the pluripotent stem cell is an embryonic stem cell or an induced pluripotent stem cell. [0537] Embodiment 12. The method of any one of embodiments 1-11, wherein the one or more integration target recognition sites is incorporated at one or more loci associated with HLA Class I proteins, one or more loci associated with HLA Class II proteins, or a combination thereof. [0538] Embodiment 13. The method of embodiment 12, wherein the one or more integration target recognition sites is incorporated at one or more of the B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus.
[0539] Embodiment 14. The method of any one of embodiments 1-13, wherein the pluripotent stem cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. [0540] Embodiment 15. The method of embodiment 14, wherein the one or more HLA Class I proteins, one or more HLA Class II proteins are encoded in one or more chromosomal regions selected from HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DP, and HLA-DQ. [0541] Embodiment 16. The method of embodiment 14, wherein the one or more HLA Class I proteins or one or more HLA Class II proteins are selected from: B2M, and CIITA. [0542] Embodiment 17. The method of any one of embodiments 1-16, wherein delivery is performed by electroporation. [0543] Embodiment 18. The method of any one of embodiments 1-17, wherein delivery into the pluripotent stem cell occurs using one or more of a recombinant adenovirus, helper dependent adenovirus, AAV, lentivirus, HSV, anellovirus, retrovirus, Doggybone DNA, minicircle, plasmid, miniDNA, nanoplasmid, exosome, fusosome, mRNA, RNP, or lipid nanoparticle. [0544] Embodiment 19. The metho of any one of embodiments 1-16, wherein delivery is performed by transfection. [0545] Embodiment 20. The method of embodiment 19, wherein delivery comprises transfecting mRNA encoding the gene editor protein, the one or more guide gRNA or two guide RNAs, and the donor polynucleotide template, wherein the donor polynucleotide template is selected from a mini circle, a nanoplasmid, and a miniDNA. [0546] Embodiment 21. The method of any one of embodiments 1-20, wherein the one or more integration target recognition sites is specific for a serine integrase. [0547] Embodiment 22. The method of any one of embodiments 1-21, wherein the one or more integration target recognition sites is an attB or attP site. [0548] Embodiment 23. The method of any one of embodiments 1-21, wherein the one or more integration target recognition sites is a modified attB or attP site. [0549] Embodiment 24. The method of any one of embodiments 1-23, wherein the one or more integration target recognition sites is specific for BxB1 or a modified BxB1.
[0550] Embodiment 25. The method of any one of embodiments 1-24, wherein the one or more integration target recognition sites is comprised of 38 or 46 nucleotides. [0551] Embodiment 26. The method of any one of embodiments 1-25, wherein the one or more guide RNA or the one or more guide RNA complex comprises a chemical modification. [0552] Embodiment 27. The method of any one of embodiments 1-26, wherein the donor polynucleotide template encodes for one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof. [0553] Embodiment 28. The method of embodiment 27, wherein expression of the one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof, is driven by a pluripotent stem cell-specific promoter. [0554] Embodiment 29. The method of embodiment 27, wherein expression of the one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof, is driven by a constitutive promoter. [0555] Embodiment 30. The method of any one of embodiments 27-29, wherein the one or more inducible suicide genes is selected from: caspase9, cytosine deasminase, and thymidine kinase. [0556] Embodiment 31. The method of embodiment 30, wherein the one or more inducible suicide genes is a controllable caspase9. [0557] Embodiment 32. The method of embodiment 31, wherein AP20187 (or an analog thereof) controls activity of Caspase9 or AP21967 (or an analog thereof) controls activity of Caspase9. [0558] Embodiment 33. The method of embodiment 31, further comprising a second inducible suicide gene, wherein the second inducible suicide gene comprises a thymidine kinase. [0559] Embodiment 34. The method of embodiment 33, wherein the polynucleotide encoding for the thymidine kinase is operably linked to the controllable capase9 protein using a 2A self-cleaving peptide or an internal ribosome entry site. [0560] Embodiment 35. The method of any one of embodiments 1-34, wherein the one or more exogenous polypeptides capable of modulating an immune response is selected from: CD47, PDL- 1, B2M-HLA-E, HLA-G, HACD16, 41BBL, CD3, CD4, CD8, CD137, CD80, and A2AR, or a combination thereof.
[0561] Embodiment 36. The method of embodiment 35, wherein the donor polynucleotide template encodes a CD47, PDL1, and B2M-HLA-E. [0562] Embodiment 37. The method of embodiment 36, wherein the polynucleotide template encoding CD47, PDL1 and B2M-HLA-E are separated by a 2A self-cleaving peptide, an internal ribosome entry site, or a combination thereof. [0563] Embodiment 38. The method of any one of embodiments 27-37, wherein the donor polynucleotide template further comprises a polynucleotide sequence encoding a tag. [0564] Embodiment 39. The method of any one of embodiments 27-38, wherein the donor polynucleotide template that encodes one or more inducible suicide genes further comprises an integrase target recognition site. [0565] Embodiment 40. The method of any one of embodiments 27-39, wherein the donor polynucleotide template that encodes one or more exogenous polypeptides capable of modulating an immune response further comprises an integrase target recognition site. [0566] Embodiment 41. The method of any one of embodiments 1-40, further comprising: incorporating an additional integration target recognition site into the pluripotent stem cell genome by delivering into the cell: (i) a gene editor protein or polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of polynucleotide genomic integration; (ii) one or more guide RNA or one or more guide RNA complex, wherein the one or more guide RNA or one or more guide RNA complex is comprised of at least one polynucleotide that encodes an integrase target recognition site; and (iii) optionally, a nicking gRNA. [0567] Embodiment 42. The method of embodiment 41, further comprising: integrating a second donor polynucleotide template into the pluripotent stem cell genome at the incorporated additional target recognition site by delivering into the cell: (i) the second donor polynucleotide template, wherein the second donor polynucleotide template is comprised of an additional integration target recognition site, wherein the second donor polynucleotide is integrated into the pluripotent stem cell at the incorporated additional genomic integration target recognition site by an integrase; thereby producing a genetically modified pluripotent stem cell comprising a first polynucleotide template and a second polynucleotide template each integrated into the pluripotent stem cell genome.
[0568] Embodiment 43. The method of any one of embodiments 1-42, further comprising directing differentiation of the modified pluripotent stem cell to a hematopoietic cell. [0569] Embodiment 44. The method of embodiment 43, wherein the hematopoietic cell is selected from: hematopoietic stem and progenitor cells (HSC), pre-HSC, hematopoietic multipotent progenitor (MPP) cells, pre-T cell progenitor cells, pre-NK cell progenitor cells, T cell progenitor cells, NK cell progenitor cells, T cells, NK cells, NKT cells, or B cells. [0570] Embodiment 45. The method of any one of embodiments 1-42, further comprising directing differentiation of the modified pluripotent stem cell to a neuronal cell. [0571] Embodiment 46. The method of embodiments 45, wherein the neuronal cell is selected from: a neural progenitor cell (NPC), a forebrain neuron, a dopaminergic neuron, a motor neuron, and a sensory neuron. [0572] Embodiment 47. The method of any one of embodiments 1-42, further comprising directing differentiation of the modified pluripotent stem cell to a cardiac cell. [0573] Embodiment 48. The method of embodiment 47, wherein the cardiac cell is selected from: a cardiac mesodermal cell, a cardiac progenitor cell, and a cardiomyocyte. [0574] Embodiment 49. A pluripotent stem cell comprising: (a) an integration target recognition site integrated in the pluripotent stem cell genome at one or more loci associated with HLA Class I proteins, one or more loci associated with HLA Class II proteins, or a combination thereof. [0575] Embodiment 50. A pluripotent stem cell comprising: (a) a donor polynucleotide template integrated into the pluripotent stem cell genome at one or more loci associated with HLA Class I proteins, one or more loci associated with HLA Class II proteins, or a combination thereof. [0576] Embodiment 51. A pluripotent stem cell comprising: (a) an integration target recognition site that is integrated (or capable of being integrated) in the pluripotent stem cell genome at one or more loci associated with HLA Class I proteins, one or more loci associated with HLA Class II proteins, or a combination thereof; (b) a gene editor protein or a polynucleotide encoding a gene editor protein, wherein the gene editor protein is capable of incorporating the integration target recognition site into the genome; (c) one or more guide RNA, wherein the one or more guide RNA encodes an integrase target recognition site; and (d) optionally, a nicking gRNA.
[0577] Embodiment 52. The pluripotent stem cell of embodiment 51, further comprising: (e) a donor polynucleotide template, wherein the donor polynucleotide template is comprised of one or more integration target recognition site, wherein the donor polynucleotide is integrated into the pluripotent stem cell genome at the incorporated genomic integration target recognition site. [0578] Embodiment 53. The pluripotent stem cell of any one of embodiments 49-52, wherein the pluripotent stem cell is an embryonic stem cell or an induced pluripotent stem cell. [0579] Embodiment 54. The pluripotent stem cell of any one of embodiments 49-53, wherein the one or more integration target recognition sites is incorporated at one or more of the B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA- DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. [0580] Embodiment 55. The pluripotent stem cell of any one of embodiments 49-54, wherein the donor polynucleotide template is incorporated at one or more of the B2M locus, CIITA locus, HLA-A locus, HLA-B locus, HLA-C locus, HLA-DR locus, HLA-DP locus, HLA-DQ locus, TAP1 locus, TAP2 locus, LRC5 locus, CCR5 locus, CXCR4 locus, PD1 locus, LAG3 locus, TIM3 locus, RFXAP locus, RFX5 locus, or RFXANK locus. [0581] Embodiment 56. The pluripotent stem cell of any one of embodiments 49-55 wherein the pluripotent stem cell comprises deletion or reduced expression of one or more HLA Class I proteins, one or more HLA Class II proteins, or a combination thereof. [0582] Embodiment 57. The pluripotent stem cell of embodiment 56, wherein the one or more HLA Class I proteins or one or more HLA Class II proteins are selected from: B2M and CIITA. [0583] Embodiment 58. The pluripotent stem cell of any one of embodiments 49-57, wherein the integration target recognition site is an attB or attP site. [0584] Embodiment 59. The pluripotent stem cell of any one of embodiments 49-58, wherein the integration target recognition site is a modified attB or attP site. [0585] Embodiment 60. The pluripotent stem cell of any one of embodiments 49-59, wherein the integration target recognition site is specific for BxB1 or a modified BxB1. [0586] Embodiment 61. The pluripotent stem cell of any one of embodiments 49-60, wherein the integration target recognition site is comprised of 38 or 46 nucleotides.
[0587] Embodiment 62. The pluripotent stem cell of any one of embodiments 49-61, wherein the one or more guide RNA or the one or more guide RNA complex comprises a chemical modification. [0588] Embodiment 63. The pluripotent stem cell of any one of embodiments 49-62, wherein the donor polynucleotide template encodes for one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof. [0589] Embodiment 64. The pluripotent stem cell of embodiment 63, wherein expression of the one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof, is driven by a pluripotent stem cell-specific promoter. [0590] Embodiment 65. The pluripotent stem cell of embodiment 63, wherein expression of the one or more inducible suicide genes, one or more exogenous polypeptides capable of modulating an immune response, or a combination thereof, is driven by a constitutive promoter. [0591] Embodiment 66. The pluripotent stem cell of any one of embodiments 63-65, wherein the one or more inducible suicide genes is select from: caspase9, cytosine deasminase, and thymidine kinase. [0592] Embodiment 67. The pluripotent stem cell of embodiment 66, wherein the one or more inducible suicide genes is a controllable caspase9. [0593] Embodiment 68. The pluripotent stem cell of embodiment 67, wherein AP20187 (or analog thereof) controls activity of Caspase9 or AP21967 (or analog thereof) controls activity of Caspase9. [0594] Embodiment 69. The pluripotent stem cell of embodiment 67, further comprising a second inducible suicide gene, wherein the second inducible suicide gene comprises a thymidine kinase. [0595] Embodiment 70. The pluripotent stem cell of embodiment 69, wherein the polynucleotide encoding for the thymidine kinase is operably linked to the controllable capase9 protein using a 2A self-cleaving peptide or an internal ribosome entry site. [0596] Embodiment 71. The pluripotent stem cell of any one of embodiments 63-70, wherein the one or more exogenous polypeptides capable of modulating an immune response is selected from:
CD47, PDL-1, B2M-HLA-E, HLA-G, HACD16, 41BBL, CD3, CD4, CD8, CD137, CD80, and A2AR, or a combination thereof. [0597] Embodiment 72. The pluripotent stem cell of embodiment 71, wherein the donor polynucleotide template encodes a CD47, PDL1, and B2M-HLA-E. [0598] Embodiment 73. The pluripotent stem cell of embodiment 72, wherein the polynucleotide template encoding CD47, PDL1 and B2M-HLA-E are separated by a 2A self-cleaving peptide, an internal ribosome entry site, or a combination thereof. [0599] Embodiment 74. The pluripotent stem cell of any one of embodiments 63-73, wherein the donor polynucleotide template further comprises a polynucleotide sequence encoding a tag. [0600] Embodiment 75. The pluripotent stem cell of embodiments 63-71, wherein the one or more inducible suicide genes further comprise an integrase target recognition site. [0601] Embodiment 76. The pluripotent stem cell of any one of embodiments 63-75, wherein the one or more exogenous polypeptides capable of modulating an immune response further comprises an integrase target recognition site. [0602] Embodiment 77. A composition comprising the pluripotent stem cell of embodiments 49- 76. A pharmaceutical composition one or more of the pluripotent stem cells of claims 49-76 and a pharmaceutically acceptable excipient. 8. EXAMPLES 8.1. Materials [0603] Primers and probes used in ddPCR experiments described in the Examples can be found in Table 13.

Table 13. ddPCR Primers and Probes

8.2. Example 1: Dual atgRNA-mediated beacon placement within the B2M or CIITA loci in iPSC [0604] To demonstrate and optimize attB beacon placement (i.e., incorporation into the genome of the integrase target recognition site) at the B2M locus or the CIITA locus within iPSCs,
a dual atgRNA approach to beacon placement was used. A non-limiting example of a dual atgRNA approach for beacon placement within an iPSC genome is as shown in FIG.6 (left panel showing example atgRNAs and right panel showing a schematic of the dual atgRNA approach). The dual atgRNAs (forward and reverse atgRNAs) each included a portion of the 38 bp attB insertion site within a segment of the reverse transcriptase template (see, e.g., FIGs.7A-7B) (Table 12). The protospacer sequences (i.e., a sequence/domain capable of guiding the gene editor protein or prime editor fusion protein to site-specifically nick the iPSC genome) were initially selected from the literature (see FIG.6 and FIG.9). [0605] A non-limiting example of a method of generating an iPSC having an integration recognition site site-specifically integrated into the iPSC genome is shown in FIG.8. [0606] iPSC lines ACS-1030 (iPSC1) and ACS-1026 (iPSC2) were purchased from ATCC and cultured as undifferentiated iPSCs grown on Cell Basement Membrane (ATCC)-coated plates in Pluripotent Stem Cell SFM XF/FF media (ATCC). Undifferentiated iPSCs were electroporated with prime editor fusion protein (2 micrograms mRNA encoding prime editor fusion protein) and atgRNA (50 picomoles). Electroporation was performed using a Neon Transfection System (ThermoFisher) with a Neon P10 tip at 1200V, 30 msec, 1 pulse. Following electroporation, the electroporated iPSCs were plated on Cell Basement Membrane-coated 48 well plates in Pluripotent Stem Cell SFM XF/FF media supplemented with 10 µM Rho Kinase (ROCK) inhibitor Y27632 and allowed to recover for about 24 hours. After 24 hours, media was changed and cells were cultured for an additional 72 hours. DNA was harvested using LGC QuickExtract buffer and beacon placement at the B2M locus and/or the CIITA locus was measured using ddPCR and/or AmpSeq. [0607] FIGs. 10A-10B show beacon placement in iPSC lines ACS-1030 (iPSC1) and ACS- 1026 (iPSC2) at B2M exon 1 and/or CIITA exon 2 for each iPSC line. FIG.10A (left panel) shows beacon placement in iPSC line 1 (ACS-1030) at the B2M locus was between about 15% to about 95% as measured by ddPCR and between about 30% to about 95% as measured by AmpSeq. Additionally, FIG.10A shows beacon placement in iPSC line 1 (ACS-1030) at the CIITA locus was between about 25% to about 45% as measured by ddPCR and between about 30% to about 55% as measured by AmpSeq. FIG.10B shows beacon placement in iPSC line 2 (ACS-1026) at the B2M locus was between about 10% to about 75% as measured by ddPCR. FIG. 10B also shows beacon placement in iPSC line 2 (ACS-1026) at the CIITA locus was between about 10% to about 15% as measured by ddPCR.
[0608] Overall, this data showed efficient beacon placement in iPSCs at both the B2M and CIITA loci. 8.3. Example 2: Concurrent beacon placement at B2M and CIITA loci in iPSCs using a dual atgRNA approach at each locus [0609] To demonstrate and optimize concurrent attB beacon placement (i.e., integration recognition site placement or incorporation) at the B2M and CIITA loci within an iPSC, a dual atgRNA approach to beacon placement was used for beacon placement at each locus. The same dual atgRNAs as described in Example 1 were used in this Example. A non-limiting example of a method of generating an iPSC where the method includes concurrent site-specific integration of integration recognition sites in the B2M locus and CIITA locus is shown in FIG.8. [0610] iPSC lines ACS-1030 (iPSC1) and ACS-1026 (iPSC2) were cultured as undifferentiated iPSCs on Cell Basement Membrane (ATCC)-coated plates in Pluripotent Stem Cell SFM XF/FF media (ATCC). Undifferentiated iPSCs were electroporated with prime editor fusion protein (2 micrograms mRNA encoding prime editor fusion protein) and atgRNA (50 picomoles). Electroporation was performed using the Neon Transfection System with a Neon P10 tip at 1200V, 30 msec, 1 pulse. Following electroporation, the electroporated iPSCs were plated on Cell Basement Membrane coated 48 well plates in Pluripotent Stem Cell SFM XF/FF media supplemented with 10 µM ROCK-inhibitor Y27632 and allowed to recover for about 24 hours. After 24 hours, media was changed, and cells were cultured for an additional 72 hours. DNA was harvested using LGC QuickExtract buffer and beacon placement at the B2M locus and/or the CIITA locus was measured using ddPCR and/or AmpSeq. [0611] FIGs.11A-11B shows concurrent beacon placement at B2M and CIITA loci using the dual atgRNA approach for beacon placement at each locus as described above. FIG.11A shows ddPCR plots, with the top panel showing data for target specific probes and the bottom panel showing data for control probes. FIG. 11B shows a summary histogram from the ddPCR data presented in the FIG.11A. [0612] Overall, FIGs. 11A-11B show successful concurrent beacon placement at B2M and CIITA loci with at least 84.9% beacon placement for B2M and at least 51.3% beacon placement for CIITA. [0613] For iPS cell line generation, electroporated iPSCs were plated on Cell Basement Membrane-coated plates in Pluripotent Stem Cell SFM XF/FF media and allowed to recover. iPSCs were plated at a density suitable to allow the single cells to grow into iPSC colonies that
could be picked and expanded for purposes of cell line generation. During initial colony expansion (i.e., prior to picking), iPSCs were grown in Pluripotent Stem Cell SFM XF/FF media supplemented with 10 µM ROCK inhibitor Y27632. About 7-14 days following plating, colonies were picked, disassociated into clumps (e.g., no less than 4 cells per clump) and re-plated onto a Cell Basement Membrane-coated dish. The picked iPSC lines were expanded, analyzed for beacon placement, and cryopreserved. [0614] Analysis of beacon placement in the iPSC lines generated according to the methods described above is shown in FIGs. 12A-12B. FIG. 12A shows raw ddPCR data for beacon placement at the B2M locus and the CIITA locus for 22 iPSC lines. FIG. 12B is a histogram summarizing ddPCR data for three iPSC lines: line 1, line 8, and line 9. Line 1 and line 9 show 100% bi-allelic beacon placement at both B2M and CIITA loci. AmpSeq was used to confirm the ddPCR data. FIG.13 shows AmpSeq data for 6 iPSC lines including lines 1, 8, 9, 16, 17, and 22. The AmpSeq data did indeed confirm the ddPCR data from FIGs. 12A-12B. Based on the data from FIGs.12A-12B and FIG.13, iPSC lines 16, 17 and 22 showed concurrent, bi-allelic beacon placement at both B2M and CIITA loci. Therefore, these lines were selected for programmable gene insertion (i.e., integration of donor polynucleotide templates) into one or both of the B2M locus and the CIITA locus. 8.4. Example 3: Concurrent Integration of 6 kilobase donor templates at beacons incorporated into the B2M and CIITA loci using electroporation [0615] The iPS cell lines generated in Example 2 were used to assess concurrent integration integrate donor polynucleotide templates at the B2M locus, the CIITA locus, or both. In this Example, a first donor polynucleotide template (pDY-GG-EF1aGFP (SEQ ID NO: 618) about 6 kilobase (kb) in size having an AttP integration recognition site comprising a GG central dinucleotide was targeted to the AttB integration recognition site that was site-specifically integrated at the B2M locus. This Example also included a second donor polynucleotide template (pL1113 (SEQ ID NO: 619) about 5 kb in size having an AttP integration recognition site comprising a GT central dinucleotide that was targeted to the AttB integration recognition site site- specifically integrated at the CIITA locus. [0616] At Day 0, the undifferentiated iPS cell line (line #17) was electroporated with plasmid DNA encoding BxB1 as well as plasmid DNA from the first donor polynucleotide template and/or plasmid DNA from the second donor polynucleotide template. In particular, a single cell suspension of 100,000 iPSCs in 10 µL E1 buffer was combined with plasmid DNA according to the conditions specified in the Table 14.
10. EQUIVALENTS AND INCORPORATION BY REFERENCE [0667] All references cited herein are incorporated by reference to the same extent as if each individual publication, database entry (e.g., Genbank sequences or GeneID entries), patent application, or patent, was specifically and individually indicated incorporated by reference in its entirety, for all purposes. This statement of incorporation by reference is intended by Applicants, pursuant to 37 C.F.R. §1.57(b)(1), to relate to each and every individual publication, database entry (e.g., Genbank sequences or GeneID entries), patent application, or patent, each of which is clearly identified in compliance with 37 C.F.R. §1.57(b)(2), even if such citation is not immediately adjacent to a dedicated statement of incorporation by reference. The inclusion of dedicated statements of incorporation by reference, if any, within the specification does not in any way weaken this general statement of incorporation by reference. Citation of the references herein is not intended as an admission that the reference is pertinent prior art, nor does it constitute any admission as to the contents or date of these publications or documents. [0668] While the invention has been particularly shown and described with reference to a preferred embodiment and various alternate embodiments, it is understood by persons skilled in the relevant art that various changes in form and details can be made therein without departing from the spirit and scope of the invention.