Figure 6.

Histone mark-binding proteins at bivalent promoters. Several binding proteins recognizing H3K4me3 and H3K27me3 may be present at bivalent genes. TFIID, SAGA, and CHD1 complexes, among others, are recruited at least in part by H3K4me3. Cfp1 binds to H3K4me3 as a subunit of SET1A/B complexes, supporting further H3K4me3 methylation. H3K4me3, together with other factors, prevents DNMT3-mediated DNA methylation. On the other hand, H3K27me3 recruits certain PRC1 complexes but also reinforces binding of PRC2 itself through interaction with its EED subunit. PRC1 complexes compact chromatin and interfere with preinitiation complex (PIC) assembly. Some PRC1 complexes further catalyze H2.Aub1, which may impair FACT recruitment, among other effects. See Figure 4 for a key of the histone modifications present in this figure.