Recruitment of Polycomb Repressive Complexes

The historical model for Polycomb complex recruitment involves recruitment of PRC2 which tri-methylates histone H3 lysine 27 (H3K27me3); H3K27me3 is subsequently recognised by CBX recruiting the PRC1 complex which mono-ubiquitylates H2AK119 (H2AK119ub1).

Our results, published in Cell, were instrumental in overturning this recruitment model and showed that PRC1 can be recruited independently of PRC2 and H3K27me3. We isolated a novel Polycomb repressive complex from ES cells, RYBP-PRC1. This complex is mutually exclusive to the canonical PRC1 complex containing CBX.

We showed that the RYBP-PRC1 complex is responsible for the PRC2 independent genome wide recruitment of PRC1 (Figure 2).

Check out our paper in Cell.

Mechanisms of PRC1 recruitment

Figure 2. Mechanisms of PRC1 recruitment in mammalian cells