Background：

Activates insulin， somatostatin， glucokinase， islet amyloid polypeptide and glucose transporter type 2 gene transcription. Particularly involved in glucose-dependent regulation of insulin gene transcription. As part of a PDX1:PBX1b:MEIS2b complex in pancreatic acinar cells is involved in the transcriptional activation of the ELA1 enhancer; the complex binds to the enhancer B element and cooperates with the transcription factor 1 complex (PTF1) bound to the enhancer A element. Binds preferentially the DNA motif 5’-[CT]TAAT[TG]-3’. During development， specifies the early pancreatic epithelium， permitting its proliferation， branching and subsequent differentiation. At adult stage， required for maintaining the hormone-producing phenotype of the beta-cell.