Molecular Biology

What brings PRC2 to chromatin?

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Science  17 Nov 2017:
Vol. 358, Issue 6365, pp. 883-884
DOI: 10.1126/science.358.6365.883-b

Polycomb repressive complex 2 (PRC2), an essential epigenetic regulator, silences gene expression by methylating histone H3. DNA, protein, and RNA have all been previously proposed to recruit PRC2 to chromatin. Using biochemistry and single-molecule imaging, respectively, Wang et al. and Choi et al. show that protein-free DNA predominantly contributes to PRC2's affinity with chromatin in test tubes. Choi et al. also identify a DNA-binding domain in PRC2 and a protein cofactor that increases this binding. Wang et al. further show that RNA sequesters PRC2 away from chromatin by competing with DNA. These results help explain contradictory published observations and provide a framework to test PRC2 recruitment to chromatin in cells.

Nat. Struct. Mol. Biol. 10.1038/nsmb.3488, 10.1038/nsmb.3487 (2017).

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