Activates insulin, somatostatin, glucokinase, islet amyloid polypeptide and glucose transporter type 2 gene transcription. Particularly involved in glucose-dependent regulation of insulin gene transcription. 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. Insulin promoter factor 1 is an islet-specific protein that activates transcription of the insulin andsomatostatin genes. It is a key regulator of islet peptide hormone expressionn and also plays an essential role in pancreatic development. Mutations in this gene may be involved in several disorders of the pancreas or in diabetes mellitus. Belongs to the Antp homeobox family. IPF1/XlHbox-8 subfamily. & Contains 1 homeobox DNA-binding domain. Subcellular Location: Nucleus. Tissue Specificity: Duodenum and pancreas.