CTCF mediates chromatin looping via N-terminal domain-dependent cohesin retention
CTCF mediates chromatin looping via N-terminal domain-dependent cohesin retention
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DOI：
10.1073/pnas.1911708117
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发表时间：
2020-01-28
影响因子：
11.1
通讯作者：
Lobanenkov, Victor V.
中科院分区：
文献类型：
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作者：
Pugacheva, Elena M.;Kubo, Naoki;Lobanenkov, Victor V.
DNA结合蛋白CCCTC结合因子（CTCF）和粘附素复合物共同作用于哺乳动物细胞中的染色质结构，但这一过程的分子细节仍不清楚。在这里，我们证明了CTCF N末端内的79-aa区域对于在CTCF结合位点的粘着蛋白定位和染色质环的形成是必不可少的。然而，融合到人工锌指的CTCF的N末端不足以将粘附素重定向到非CTCF结合位点，表明CTCF中缺乏负责粘附素定位的自主功能结构域。BORIS（CTCFL）是CTCF的一种生殖细胞特异性蛋白质，它不能将粘附素锚在CTCF DNA结合位点上。此外，CTCF-BORIS嵌合构建体提供的证据表明，除了CTCF的N末端之外，前两个CTCF锌指，以及可能的CTCF-DNA复合物的3D几何形状，也参与了粘附素保留。基于这些知识，我们能够将BORIS转化为CTCF中的粘附素定位，从而提供CTCF保留粘附素能力的额外分子细节。两者合计，我们的数据提供了深入了解的过程中，DNA结合的CTCF约束凝聚运动，以塑造时空基因组组织。
The DNA-binding protein CCCTC-binding factor (CTCF) and the cohesin complex function together to shape chromatin architecture in mammalian cells, but the molecular details of this process remain unclear. Here, we demonstrate that a 79-aa region within the CTCF N terminus is essential for cohesin positioning at CTCF binding sites and chromatin loop formation. However, the N terminus of CTCF fused to artificial zinc fingers was not sufficient to redirect cohesin to non-CTCF binding sites, indicating a lack of an autonomously functioning domain in CTCF responsible for cohesin positioning. BORIS (CTCFL), a germline-specific paralog of CTCF, was unable to anchor cohesin to CTCF DNA binding sites. Furthermore, CTCF-BORIS chimeric constructs provided evidence that, besides the N terminus of CTCF, the first two CTCF zinc fingers, and likely the 3D geometry of CTCF-DNA complexes, are also involved in cohesin retention. Based on this knowledge, we were able to convert BORIS into CTCF with respect to cohesin positioning, thus providing additional molecular details of the ability of CTCF to retain cohesin. Taken together, our data provide insight into the process by which DNA-bound CTCF constrains cohesin movement to shape spatiotemporal genome organization.