Genome-wide maps of histone modifications in male and female mouse liver
Here we map six chromatin modifications -- H3K4me1, H3K4me3, H3K27ac, H3K36me3, H3K9me3, and H3K27me3 -- genome-wide in male and female mouse liver in order to identify histone modifications that characterize sex-biased genes and sex-biased DNase hypersensitive sites and their regulation by plasma growth hormone (GH) profiles, which are sexually dimorphic. We find distinct mechanisms of regulation in male liver and female liver: sex-dependent K27me3-mediated repression is an important mechanism of repression of female-biased, but not of male-biased, genes, and a sex-dependent K4me1 distribution, suggesting nucleosome repositioning by pioneer factors, is observed at male-biased, but not female-biased, regulatory sites.  STAT5-mediated activation is most strongly associated with sex-biased chromatin modifications, while BCL6-mediated repression primarily occurs in association with sex-independent chromatin modifications, both at binding sites and at target genes. These samples are part of a study on chromatin states in male and female mouse and their role in sex-biased liver gene expression (A Sugathan and DJ Waxman (2013) Molec Cell Biol). Overall design: Examination of six different histone modifications in male and female mouse liver.