Dynamic PRC1-CBX8 stabilizes a porous structure of chromatin condensates.

ABSTRACT: The compaction of chromatin is a prevalent paradigm in gene repression. Chromatin compaction is commonly thought to repress transcription by restricting chromatin accessibility. However, the spatial organization and dynamics of chromatin compacted by gene-repressing factors are unknown. Here, using cryo-electron tomography, we solved the three-dimensional structure of chromatin condensed by the polycomb repressive complex 1 (PRC1) in a complex with CBX8. PRC1-condensed chromatin is porous and stabilized through multivalent dynamic interactions of PRC1 with chromatin. Mechanistically, positively charged residues on the internally disordered regions of CBX8 mask negative charges on the DNA to stabilize the condensed state of chromatin. Within condensates, PRC1 remains dynamic while maintaini

SUBMITTER: Uckelmann M 

PROVIDER: S-EPMC11919719 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature