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bioRxiv · 10.1101/2025.08.25.672128

Mutual Antagonism Between PRC1 Condensates and SWI/SNF in Chromatin Regulation

Niekamp, S.·Marr, S. K.·Sanon, R.·Schneider, P. C.·Subramanian, R.·Kingston, R. E.
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Abstract

Opposing activities of conserved chromatin regulatory complexes, such as the Polycomb Repressive Complex 1 (PRC1) and the activating chromatin remodeler SWI/SNF play critical roles in regulating gene expression during development and differentiation. The mechanisms by which these complexes compete to regulate chromatin states remain poorly understood. We combine single-molecule analysis and genomic approaches in cultured cells to demonstrate that the condensate-forming properties of PRC1 play an important role in excluding SWI/SNF from chromatin. Consistently, PRC1 compositions with a higher propensity for condensate formation are more effective in preventing SWI/SNF binding. Conversely, SWI/SNF-bound chromatin significantly reduces PRC1 binding and subsequent condensate formation. Notably, SWI/SNF can suppress PRC1 condensate formation in an ATP-hydrolysis independent manner. We propose that the condensate properties of different PRC1 compositions drive mutual PRC1-SWI/SNF antagonism to properly balance these competing regulatory activities during development.

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Niekamp, S., Marr, S. K., Sanon, R., Schneider, P. C., Subramanian, R., Kingston, R. E.. 2025-08-26. Mutual Antagonism Between PRC1 Condensates and SWI/SNF in Chromatin Regulation. https://doi.org/10.1101/2025.08.25.672128

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