Redundant and specific roles of cohesin STAG subunits in chromatin looping and transcriptional control
Redundant and specific roles of cohesin STAG subunits in chromatin looping and transcriptional control
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DOI：
10.1101/gr.253211.119
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发表时间：
2020-04-01
期刊：
影响因子：
7
通讯作者：
Wendt, Kerstin S.
中科院分区：
文献类型：
--
作者：
Casa, Valentina;Gines, Macarena Moronta;Wendt, Kerstin S.
黏连蛋白是一种环状多蛋白复合物，在分化和发育过程中对3D基因组组织和转录调控至关重要。它还赋予姐妹染色单体凝聚力并促进DNA损伤修复。除了其核心亚基SMC 3、SMC 1A和RAD 21之外，体细胞中的粘着蛋白还含有两个正向STAG亚基STAG 1或STAG 2中的一个。这些可变亚基如何影响粘附素复合物的功能尚不清楚。STAG 1-和STAG 2-粘着蛋白最初被提出分别在端粒和着丝粒组织粘着。在这里，我们发现多余的和特定的作用，STAG 1和STAG 2在基因调控和染色质循环使用HCT 116细胞与生长素诱导降解决定子（AID）标签融合到STAG 1或STAG 2。在快速耗尽任一亚基后，我们进行了高分辨率Hi-C、基因表达和连续ChIP研究，以表明STAG 1和STAG 2不共同占据单个结合位点，并且具有不同的方式来影响循环和基因表达。这些发现进一步支持通过直接随机光学重建显微镜（dSTORM）超分辨率成像的单分子定位。由于STAG亚基的体细胞和先天性突变与癌症（STAG 2）和先天性异常的智力残疾综合征（STAG 1和STAG 2）相关，我们使用人类神经干细胞验证了STAG 1-/STAG 2-依赖性，从而突出了它们在特定疾病背景下的重要性。
Cohesin is a ring-shaped multiprotein complex that is crucial for 3D genome organization and transcriptional regulation during differentiation and development. It also confers sister chromatid cohesion and facilitates DNA damage repair. Besides its core subunits SMC3, SMC1A, and RAD21, cohesin in somatic cells contains one of two orthologous STAG subunits, STAG1 or STAG2. How these variable subunits affect the function of the cohesin complex is still unclear. STAG1- and STAG2-cohesin were initially proposed to organize cohesion at telomeres and centromeres, respectively. Here, we uncover redundant and specific roles of STAG1 and STAG2 in gene regulation and chromatin looping using HCT116 cells with an auxin-inducible degron (AID) tag fused to either STAG1 or STAG2. Following rapid depletion of either subunit, we perform high-resolution Hi-C, gene expression, and sequential ChIP studies to show that STAG1 and STAG2 do not co-occupy individual binding sites and have distinct ways by which they affect looping and gene expression. These findings are further supported by single-molecule localizations via direct stochastic optical reconstruction microscopy (dSTORM) super-resolution imaging. Since somatic and congenital mutations of the STAG subunits are associated with cancer (STAG2) and intellectual disability syndromes with congenital abnormalities (STAG1 and STAG2), we verified STAG1-/STAG2-dependencies using human neural stem cells, hence highlighting their importance in particular disease contexts.