Transcriptome comparison of PAX6 ablated mouse beta cells to WT beta cells, ChIP-seq analysis of PAX6 bound sites both in mouse and human beta cell lines (Min6 and EndoC), and ChIP-seq analysis fo histone mark H3K9ac on mouse pancreatic beta cells.

Here, we report a key role for the transcription factor Pax6 in the maintenance of adult beta-cell identity and function. Pax6 is down regulated in beta-cells of diabetic db/db mice and in wild type mice treated with an insulin receptor antagonist, revealing metabolic control of expression. Deletion of Pax6 in beta-cells of adult mice leads to lethal hyperglycemia and ketosis, due to loss of beta-cell function and expansion of alpha-cells. Lineage tracing, transcriptome, and chromatin analyses show that Pax6 is a direct activator of beta-cell genes, maintaining mature beta-cell function and identity. In parallel, Pax6 binds promoters and enhancers to repress alternative islet cell genes including ghrelin, glucagon, and somatostatin. Chromatin analysis and shRNA-mediated gene suppression experiments indicate a similar function of PAX6 in human beta-cells. Reduced expression of Pax6 in metabolically stressed beta-cells may contribute to beta-cell failure and alpha-cell dysfunction in diabetes. Overall design: RNA profiles of pancreatic beta cells from 6-8 weeks old ßPAX6 transgenic mice (MIP-CreER; Pax6lox/lox; Rosa26-LSL-YFP) and from their control littermates (Rosa26-LSL-YFP) were generated byRNAseq. Whole genome map of PAX6 bound sites were generated by ChIP-seq on Min6 and EnodC cells (n=3) whole genome map of histones enriched for H3K9ac modification was generated by ChIP-seq on pancreatic beta cells from 16 months old Bl6 mice .