Characterization and regulation of the hb9/mnx1 beta-cell progenitor specific enhancer in zebrafish

► Beta-cell progenitor enhancer localizes to non-conserved hb9 promoter sequences. ► E-boxes are required for hb9 induction. ► Induction is independent of Ngn3 and NeuroD. ► Pax6b activates enhancer. ► Pax6b is required for hb9 maintenance.