Crucial role of PDX-1 in pancreas development, beta-cell differentiation, and induction of surrogate beta-cells.

Pancreatic and duodenal homeobox factor-1 (PDX-1) plays a crucial role in pancreas development, beta-cell differentiation, and maintaining mature beta-cell function. At an early stage of embryonic development, PDX-1 is initially expressed in the gut region when the foregut endoderm becomes committed to common pancreatic precursor cells. During pancreas development, PDX-1 expression is maintained in precursor cells, and later it becomes restricted to beta-cells. In mature beta-cells, PDX-1 transactivates the insulin gene and other genes involved in glucose sensing and metabolism, such as GLUT2 and glucokinase. MafA is a recently isolated beta-cell-specific transcription factor which functions as a potent activator of insulin gene transcription. During pancreas development, MafA expression is first detected at the beginning of the principal phase of insulin-producing cell production. Furthermore, these transcription factors play a crucial role in inducing surrogate beta-cells from non-beta-cells and thus could be therapeutic targets for diabetes.