H3K27 methylation mediated by the histone methyltransferase complex PRC2 is critical for
transcriptional regulation, Polycomb silencing, Drosophila segmentation, mammalian X
chromosome inactivation, and cancer. PRC2-mediated H3K27 methylation can spread
along the chromatin and propagate the repressive chromatin environment; thus, chromatin
components that antagonize the activity of PRC2 are important for restraining Polycomb
silencing. Here we report that in HeLa cells, H3 histones unmethylated at Lys-36 are mostly …