GSE24326
Genome-wide profiling of H3K56 acetylation and transcription factor binding sites in human adipocytes
We use ChIP-seq to discover the genome-wide sites of acetylation of lysine 56 of the histone H3 (H3K56), which is a target of three histone modifying enzymes with known roles in diabetes and insulin resistance, in human adipocytes derived from mesenchymal stem cells. Surprisingly, we find that a very large fraction of genes show some level of acetylation on H3K56, but the highest levels of acetylation are associated with genes previously reported to be involved  in type 2 diabetes.  Using computational methods, we propose that the transcription factor E2F4 may be involved in recruiting histone modifying enzymes to these sites.  We confirm this prediction by measuring the binding of E2F4 using ChIP-seq. We also examine the binding of two other proteins using ChIP-Seq:  HSF-1 and C/EBPa .  HSF-1 is a master regulator of stress responses, and is a target of the same histone modifiers as H3K56.  We find a high degree of overlap between HSF-1 binding and H3K56 acetylation even in cells that are not stressed.  By contrast, C/EBPa , which is not known to be modified by these enzymes, shows much less overlap with the sites of H3K56 acetylation.   Our results represent the first mapping of the regulatory code of human adipocytes. Overall design: Examination of H3K56 acetylation sites and E2F4,C/EBPa and HSF-1 binding sites in human adipocytes.