Live-cell imaging reveals the dynamics of PRC2 and recruitment to chromatin by SUZ12-associated subunits
- Daniel T. Youmans1,2,3,4,
- Jens C. Schmidt1,2,5 and
- Thomas R. Cech1,2,4
- 1BioFrontiers Institute, University of Colorado at Boulder, Boulder, Colorado 80303, USA;
- 2Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80303, USA;
- 3Anschutz Medical Campus, University of Colorado at Denver, Aurora, Colorado 80045, USA;
- 4Howard Hughes Medical Institute, University of Colorado at Boulder, Boulder, Colorado 80303, USA
- Corresponding author: thomas.cech{at}colorado.edu
Abstract
Polycomb-repressive complex 2 (PRC2) is a histone methyltransferase that promotes epigenetic gene silencing, but the dynamics of its interactions with chromatin are largely unknown. Here we quantitatively measured the binding of PRC2 to chromatin in human cancer cells. Genome editing of a HaloTag into the endogenous EZH2 and SUZ12 loci and single-particle tracking revealed that ∼80% of PRC2 rapidly diffuses through the nucleus, while ∼20% is chromatin-bound. Short-term treatment with a small molecule inhibitor of the EED–H3K27me3 interaction had no immediate effect on the chromatin residence time of PRC2. In contrast, separation-of-function mutants of SUZ12, which still form the core PRC2 complex but cannot bind accessory proteins, revealed a major contribution of AEBP2 and PCL homolog proteins to chromatin binding. We therefore quantified the dynamics of this chromatin-modifying complex in living cells and separated the contributions of H3K27me3 histone marks and various PRC2 subunits to recruitment of PRC2 to chromatin.
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Footnotes
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Supplemental material is available for this article.
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Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.311936.118.
- Received January 17, 2018.
- Accepted April 30, 2018.
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