Figure 3.

Potential mechanisms of PRC2 recruitment to target genes. PRC2 is recruited to target genes by a combination of transcription factors and ncRNAs. A fraction of PRC2 associates with JARID2, which is required for PRC2 binding to its target genes in ES cells. JARID2 might therefore represent a core component of PRC2 in ES cells, although other PRC2 complexes exist; these contain MTF2, PHF1, and other uncharacterized factors that could represent alternative targeting mechanisms operative both during ES cell self-renewal and differentiation. Sequence-specific transcription factors (TF) and ncRNA might also recruit the PRC2 core complex to target genes during differentiation. Finally, PcG target genes are CpG-rich, and proteins binding to CpG elements such as TET1 or the histone demethylase FBXL10 might have a role in recruiting Polycomb to target genes. For additional information on the components of PRC1 and PRC2 complexes, see Morey and Helin (2010).