Figure 3.

PcG proteins and complexes. (A) PcG protein complexes discussed in this review are shown. Pcl, Jing, and Jarid2 are PRC2-associated proteins that modify the activity of PRC2 (see text). Psc/Su(z)2 and Sce (also known as dRing) are in both PRC1 and dRAF. A recent article provided compelling evidence that Scm interacts closely with PRC1, PRC2, and PhoRC, and suggested that Scm plays a key role in connecting these three complexes (Kang et al. 2015; see text). (B) PcG protein complexes are recruited to DNA by PREs. PREs have binding sites for a large number of DNA-binding proteins; Pho or Phol, Spps, GAF (encoded by the Trl gene), and Cg are shown. PRC2 trimethylates H3K27 and PRC1 inhibits transcription by a variety of mechanisms (see text). Me, methylation.