The Polycomb repressive complex 1 (PRC1) is a Polycomb group complex. It binds to histone H3K27me3 (histone H3 K27 methylation is catalyzed by PRC2) and monoubiquitinates H2A on K119. This leads to chromatin compaction, RNA polymerase II stalling and gene silencing. (Adapted from
FBrf0179742 and
FBrf0228921).