PAX6 is a PAX family transcription factor with important functions in the development of the eye, nose, central nervous system and pancreas. It is required for the differentiation of pancreatic islet alpha cells. It competes with PAX4 in binding to a common element in the glucagon, insulin and somatostatin promoters. It regulates the specification of the ventral neuron subtypes by establishing the correct progenitor domains. PAX6 isoform 5a appears to function as a molecular switch that specifies target genes. References: The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804