Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands.
Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany.
Nat Genet. 2022 Feb;54(2):194-201. doi: 10.1038/s41588-021-00988-8. Epub 2022 Jan 24.
Nucleoprotein complexes play an integral role in genome organization of both eukaryotes and prokaryotes. Apart from their role in locally structuring and compacting DNA, several complexes are known to influence global organization by mediating long-range anchored chromosomal loop formation leading to spatial segregation of large sections of DNA. Such megabase-range interactions are ubiquitous in eukaryotes, but have not been demonstrated in prokaryotes. Here, using a genome-wide sedimentation-based approach, we found that a transcription factor, Rok, forms large nucleoprotein complexes in the bacterium Bacillus subtilis. Using chromosome conformation capture and live-imaging of DNA loci, we show that these complexes robustly interact with each other over large distances. Importantly, these Rok-dependent long-range interactions lead to anchored chromosomal loop formation, thereby spatially isolating large sections of DNA, as previously observed for insulator proteins in eukaryotes.
核蛋白复合物在真核生物和原核生物的基因组组织中起着至关重要的作用。除了在局部结构和压缩 DNA 方面的作用外，一些复合物还通过介导长距离锚定的染色体环形成来影响全局组织，从而导致 DNA 的大片段空间隔离。这种兆碱基范围的相互作用在真核生物中普遍存在，但在原核生物中尚未得到证实。在这里，我们使用基于全基因组沉降的方法，发现细菌枯草芽孢杆菌中的转录因子 Rok 形成大型核蛋白复合物。通过染色体构象捕获和 DNA 位点的活体成像，我们表明这些复合物在很大的距离上相互稳健地相互作用。重要的是，这些依赖 Rok 的长距离相互作用导致锚定的染色体环形成，从而使 DNA 的大片段空间隔离，就像以前在真核生物中观察到的绝缘子蛋白一样。
