Replicational Dilution of H3K27me3 in Mammalian Cells and the Role of Poised Promoters (Molecular Cell)

Loss of PRC2 activity in dividing adult mammalian cells depletes H3K27me3 equally at all marked nucleosomes, owing mainly to replicational dilution by unmarked histones. Individual PRC2 target genes overcome the repressed state in proportion to the number of preceding cell divisions and basal levels of promoter H3K4me2/3.