MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
Life Sci Alliance. 2023 Jul 24;6(10). doi: 10.26508/lsa.202302101. Print 2023 Oct.
Polycomb repressive complex 1 (PRC1) strongly influences 3D genome organization, mediating local chromatin compaction and clustering of target loci. Several PRC1 subunits have the capacity to form biomolecular condensates through liquid-liquid phase separation in vitro and when tagged and over-expressed in cells. Here, we use 1,6-hexanediol, which can disrupt liquid-like condensates, to examine the role of endogenous PRC1 biomolecular condensates on local and chromosome-wide clustering of PRC1-bound loci. Using imaging and chromatin immunoprecipitation, we show that PRC1-mediated chromatin compaction and clustering of targeted genomic loci-at different length scales-can be reversibly disrupted by the addition and subsequent removal of 1,6-hexanediol to mouse embryonic stem cells. Decompaction and dispersal of polycomb domains and clusters cannot be solely attributable to reduced PRC1 occupancy detected by chromatin immunoprecipitation following 1,6-hexanediol treatment as the addition of 2,5-hexanediol has similar effects on binding despite this alcohol not perturbing PRC1-mediated 3D clustering, at least at the sub-megabase and megabase scales. These results suggest that weak hydrophobic interactions between PRC1 molecules may have a role in polycomb-mediated genome organization.
多梳抑制复合物 1（PRC1）强烈影响 3D 基因组组织，介导局部染色质紧缩和靶位的聚类。几个 PRC1 亚基具有通过体外液-液相分离形成生物分子凝聚物的能力，并且当在细胞中标记和过表达时也是如此。在这里，我们使用 1,6-己二醇，它可以破坏类液相凝聚物，来研究内源性 PRC1 生物分子凝聚物对 PRC1 结合的靶位在局部和染色体水平上的聚类的作用。通过成像和染色质免疫沉淀，我们表明 PRC1 介导的染色质紧缩和靶向基因组位的聚类（在不同的长度尺度上）可以通过向小鼠胚胎干细胞中添加和随后去除 1,6-己二醇来可逆地破坏。解压缩和分散多梳域和簇不能仅仅归因于 1,6-己二醇处理后染色质免疫沉淀检测到的 PRC1 占有率降低，因为尽管这种醇不会干扰 PRC1 介导的 3D 聚类，但至少在亚兆碱基和兆碱基尺度上，2,5-己二醇的添加对结合具有相似的影响。这些结果表明，PRC1 分子之间的弱疏水力相互作用可能在多梳介导的基因组组织中起作用。
