Pdx1 (Pancreatic and duodenal homeobox 1), also known as insulin promoter factor 1, is a transcription factor necessary for pancreatic development, including β-cell maturation, and duodenal differentiation. Pdx1 (in rodents), otherwise known as Ipf1 (in humans), is the gene encoding it.

Function

Pancreatic development

In embryonic development, Pdx1 is expressed by a population of cells in the posterior foregut region of the definitive endoderm, and Pdx1⁺epithelial cells give rise to the developing pancreatic buds, and eventually, the whole of the pancreas—its exocrine, endocrine, and ductal cell populations. Pancreatic Pdx1⁺ cells first arise at mouse embryonic day 8.5-9.0 (E8.5-9.0), and Pdx1 expression continues until E12.0-E12.5, after which Pdx1 expression decreases and the pancreas is formed—other transcription factors are expressed, controlling the fates of the cells of the newly formed pancreas. Homozygous Pdx1 knockout mice form pancreatic buds but fail to develop a pancreas, and transgenic mice in which tetracycline application results in death of Pdx1⁺ cells are almost completely apancreatic if doxycycline (tetracycline derivative) is administered throughout the pregnancy of these transgenic mice, illustrating the necessity of Pdx1⁺ cells in pancreatic development.