FIG 4.

Target genes of Polycomb and MLL complexes in ESCs. (A) Although lineage-specific genes are classified as bivalent genes because of the presence of both H3K27me3 and H4K4me3, they are also decorated with two other repressive marks: H3K9me3 (deposited by Setdb1) and H2AK119ub (deposited by the PRC1 complex). Pluripotency factors, Polycomb, MLL complexes, and Setdb1 are required to maintain low levels of expression of lineage-specific genes. (B) cPRC1 is also recruited to lineage genes that also contain PRC2 but not the Rybp-PRC1 complex. Additionally, the Rybp-PRC1 complex is recruited to metabolic and cell cycle-related genes that are active. (C) Set1A/B complexes deposit H3K4me3 at TSS of active genes in ESCs. The MLL3/4 complexes deposit H3K4me1 at both poised and active enhancers in ESCs.