A DNA binding winged helix domain in CAF-1 functions with PCNA to stabilize CAF-1 at replication forks.
A DNA binding winged helix domain in CAF-1 functions with PCNA to stabilize CAF-1 at replication forks.
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CAF-1 中 DNA 结合翼状螺旋结构域与 PCNA 一起发挥作用，使 CAF-1 稳定在复制叉上
DOI：
10.1093/nar/gkw106
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发表时间：
2016-06-20
影响因子：
14.9
通讯作者：
Liu Y
中科院分区：
文献类型：
--
作者：
Zhang K;Gao Y;Li J;Burgess R;Han J;Liang H;Zhang Z;Liu Y
染色质组装因子1（Chromatin assembly factor 1，CAF-1）是一种组蛋白H3-H4分子伴侣，在复制偶联核小体组装过程中沉积新合成的组蛋白（H3-H4）2四聚体。然而，CAF-1如何在这一过程中发挥作用还不清楚。在这里，我们报告的晶体结构的C末端的Cac 1（Cac 1C），酵母CAF-1的亚基，和这个域的功能，在稳定CAF-1在复制叉。我们发现，Cac 1C形成一个有翼的螺旋结构域（WHD），并结合DNA的序列独立的方式。Cac 1C中的突变破坏DNA结合导致转录沉默缺陷和对DNA损伤剂的敏感性增加，并且当与PCNA结合缺陷的Cac 1突变组合时，这些缺陷加剧。对于小鼠CAF-1中的相应突变，观察到类似的表型。这些结果揭示了在真核细胞中保守的机制，其中CAF-1结合DNA的能力对于其与DNA复制叉和随后的核小体组装的关联是重要的。
Chromatin assembly factor 1 (CAF-1) is a histone H3–H4 chaperone that deposits newly synthesized histone (H3–H4)2 tetramers during replication-coupled nucleosome assembly. However, how CAF-1 functions in this process is not yet well understood. Here, we report the crystal structure of C terminus of Cac1 (Cac1C), a subunit of yeast CAF-1, and the function of this domain in stabilizing CAF-1 at replication forks. We show that Cac1C forms a winged helix domain (WHD) and binds DNA in a sequence-independent manner. Mutations in Cac1C that abolish DNA binding result in defects in transcriptional silencing and increased sensitivity to DNA damaging agents, and these defects are exacerbated when combined with Cac1 mutations deficient in PCNA binding. Similar phenotypes are observed for corresponding mutations in mouse CAF-1. These results reveal a mechanism conserved in eukaryotic cells whereby the ability of CAF-1 to bind DNA is important for its association with the DNA replication forks and subsequent nucleosome assembly.