Cis and trans determinants of epigenetic silencing by Polycomb repressive complex 2 ($)

Polycomb repressive complex 2 (PRC2) stably regulates gene expression by initiating repressive histone methylation (specifically,  trimethylation of histone H3 at Lys27, H3K27me3). Xiao et al. investigated how PRC2 targets the genes it silences. They identified several Polycomb response elements (PREs) that are binding sites for transcription factors which interact with PRC2. When selected PREs were mutated in reporter constructs, silencing was disabled, and when PREs were introduced silencing was observed, demonstrating their role in gene silencing. The identification of these PREs offers new opportunities for modulating gene expression. Nature Genet. 10.1038/ng.3937