Jarid2 binds mono-ubiquitylated H2A lysine 119 to mediate crosstalk between Polycomb complexes PRC1 and PRC2.

The Polycomb repressive complexes PRC1 and PRC2 play a central role in developmental regulation of the genome in multicellular organisms. Here the authors describe how the PRC2 cofactor Jarid2 mediates the recruitment of the PRC2 complex to chromatin via interaction with H2AK119u1.