Replicational dilution of H3K27me3 in mammalian cells and the role of poised promoters, Jadhav et al

This study investigated how cells respond to gradual erasure of H3K27me3 histone marks as the modification is diluted by 50% at each division of Polycomb Repressor Complex 2 (PRC2)-null Eed-/- intestinal stem cells (ISC). Whereas mutant post-mitotic intestinal villus cells showed derepression of PRC2-silenced target genes, the same changes in gene expression were not present in cells lacking the EZH2 methyltransferase and were not initially evident in Eed-/- ISC. This is because Ezh2-/- cells retain ~40% of basal H3K27me3 and ISC had not yet replicated a sufficient number of times to erase the mark. Over time, as ISC continued to replicate and to dilute H3K7me3 marking, PRC2 target genes became active. Genes with high basal levels of promoter H3K4me2/3 were activated earlier than genes with low levels. These Mendeley Data represent the source files for all photomicrographs (immunofluorescence, histology, immunohistochemistry) and immunoblots shown in the published study