biostudies-literatureUnknownNiekamp SNIGMS NIH HHSOpposing 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. NotablybioRxiv : the preprint server for biology2025.08.25.672128https://www.ebi.ac.uk/biostudies/studies/S-EPMC12407733biostudies-literatureMutual Antagonism Between PRC1 Condensates and SWI/SNF in Chromatin Regulation.PMC12407733R35 GM131743K99 GM155610Kingston REMarr SKSchneider PCSanon RSubramanian RNiekamp SfalseMutual Antagonism Between PRC1 Condensates and SWI/SNF in Chromatin Regulation.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. Notably2025-01-01T00:00:00Z2025 Aug2026-05-28T03:07:35.096Z2026-05-28T03:06:28.172ZS-EPMC124077334090953510.1101/2025.08.25.672128