Polycomb Repressive Complex 2 Regulates Lineage Fidelity during Embryonic Stem Cell Differentiation
(A) In ESCs, PRC2 localizes largely to developmental regulator genes, and maintains them in their repressed, and yet poised, state. (B) Proper H3K27me3 levels are necessary to activate developmental gene programs during differentiation. (C) A gain in H3K27me3 during differentiation represses alternate-lineage genes, allowing for efficient lineage restriction. (D) PRC2 antagonizes DNA methylation in cis, and may play a role in preventing the premature permanent repression of developmental genes.