Histone methylation profiles of prospectively isolated mammary epithelial subpopulations

In this study we mapped H3K27me3, H3K4me3 and H3K9me2 marks in three mammary epithelial subsets: MaSC/basal (MS), luminal progenitor (LP) and mature luminal (ML) in the steady-state. In addition, profiles were generated for H3K4me3 and H3K27me3 marks in the MaSC/basal and luminal populations from the glands of ovariectomized or mid-pregnant (12.5 days) mice as well as from control virgin mice. Overall design: We used ChIPseq analysis to determine histone modification marks in the MS, LP and ML subsets in the steady-state. We then determined the histone modification profiles of MS and sorted luminal (Lum) cells from pregnant (12.5 dP) or ovariectomized (OVX) mice and compared these with the profiles of control virgin mice in order to study the effect of hormones on the mammary epigenomes.