Jain Neha, Tamborrini Davide, Evans Brian, Chaudhry Shereen, Wilkins Bryan J, Neumann Heinz
Department of Structural Biochemistry, Max-Planck-Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
Department of Chemistry and Biochemistry, Manhattan College, 4513 Manhattan College Parkway, Bronx, NY 10471, USA.
iScience. 2020 Jul 24;23(7):101292. doi: 10.1016/j.isci.2020.101292. Epub 2020 Jun 20.
Chromatin remodeling complexes are multi-subunit nucleosome translocases that reorganize chromatin in the context of DNA replication, repair, and transcription. To understand how these complexes find their target sites on chromatin, we use genetically encoded photo-cross-linker amino acids to map the footprint of Sth1, the catalytic subunit of the RSC complex, on nucleosomes in living yeast. We find that H3 K14 acetylation induces the interaction of the Sth1 bromodomain with the H3 tail and mediates the interaction of RSC with neighboring nucleosomes rather than recruiting it to chromatin. RSC preferentially resides on H2B SUMOylated nucleosomes in vivo and shows a moderately enhanced affinity due to this modification in vitro. Furthermore, RSC is not ejected from chromatin in mitosis, but changes its mode of nucleosome binding. Our in vivo analyses show that RSC recruitment to specific chromatin targets involves multiple histone modifications likely in combination with histone variants and transcription factors.
染色质重塑复合物是多亚基核小体转位酶，可在DNA复制、修复和转录过程中重组染色质。为了解这些复合物如何在染色质上找到它们的靶位点，我们使用基因编码的光交联氨基酸来绘制RSC复合物的催化亚基Sth1在活酵母核小体上的足迹。我们发现H3 K14乙酰化诱导Sth1溴结构域与H3尾部相互作用，并介导RSC与相邻核小体的相互作用，而不是将其招募到染色质上。RSC在体内优先存在于H2B SUMO化的核小体上，并且由于这种修饰在体外显示出适度增强的亲和力。此外，RSC在有丝分裂过程中不会从染色质上被排出，而是改变其核小体结合模式。我们的体内分析表明，RSC募集到特定染色质靶点涉及多种组蛋白修饰，可能与组蛋白变体和转录因子结合。
