Abstract
The main role of pancreatic β cells is to secrete insulin in response to an increase of the blood glucose level. To accomplish this, β cells express numerous genes essential for glucose-responsive insulin secretion. To allow the expression of such strictly selected multiple sets of genes, various differentiation steps are required during pancreatic development. As is the case for other types of cells, recent studies have identified several transcription factors that control the activation and repression of a large number of genes during pancreatic development and how these factors function. Accumulation of such knowledge has revealed that transcription factors orchestrate the intricate pathways of cellular growth, death, and differentiation by direct regulation of gene expression. Amongst the transcription factors in this well-organized cascade, neurogenin 3 (Ngn3) plays a key role in determining the fate of cells in the endocrine pancreas. We recently found how signals from adjacent cells regulate the expression of Ngn3 in pancreatic precursor cell. In addition, we found that Ngn3 regulates the expression of Pax4 and Nkx2.2 cooperated with HNF factors, thus induces β cell differentiation. [J Physiol Sci. 2006;56 Suppl:S18]
