Recruitment of mismatch repair proteins to the site of DNA damage in human cells
Recruitment of mismatch repair proteins to the site of DNA damage in human cells
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DOI：
10.1242/jcs.026393
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发表时间：
2008-10-01
影响因子：
4
通讯作者：
Yasui, Akira
中科院分区：
文献类型：
--
作者：
Hong, Zehui;Jiang, Jie;Yasui, Akira
错配修复 (MMR) 蛋白通过切除 DNA 聚合酶引入的 DNA 错配来促进基因组稳定性。尽管 MMR 蛋白也已知会影响细胞对 DNA 损伤的反应，但 MMR 蛋白如何对细胞内的 DNA 损伤做出反应仍不清楚。在这里，我们发现 MMR 蛋白立即被招募到人类细胞中各种类型 DNA 损伤的位点。 MMR 蛋白以聚（ADP-核糖）依赖性方式被募集至单链断裂以及双链断裂。利用突变细胞、RNA 干扰和荧光标记蛋白的表达，我们发现 MutS beta 在 DNA 损伤位点的积累仅依赖于 MSH3 的 PCNA 结合域，而 MutS α 的积累则依赖于 MSH6 的 PCNA 结合域附近的区域。 MSH2 通过与 MSH3 或 MSH6 相互作用被招募到 DNA 损伤位点，并且是 MLH1 招募到损伤位点所必需的。此外，我们发现 MutS beta 也以核苷酸切除修复和 PCNA 依赖性方式被招募到紫外线照射的位点。因此，MMR 及其蛋白质不仅在复制中发挥作用，而且在 DNA 修复中发挥作用。
Mismatch repair (MMR) proteins contribute to genome stability by excising DNA mismatches introduced by DNA polymerase. Although MMR proteins are also known to influence cellular responses to DNA damage, how MMR proteins respond to DNA damage within the cell remains unknown. Here, we show that MMR proteins are recruited immediately to the sites of various types of DNA damage in human cells. MMR proteins are recruited to single-strand breaks in a poly(ADP-ribose)dependent manner as well as to double-strand breaks. Using mutant cells, RNA interference and expression of fluorescence-tagged proteins, we show that accumulation of MutS beta at the DNA damage site is solely dependent on the PCNA-binding domain of MSH3, and that of MutS alpha depends on a region near the PCNA-binding domain of MSH6. MSH2 is recruited to the DNA damage site through interactions with either MSH3 or MSH6, and is required for recruitment of MLH1 to the damage site. We found, furthermore, that MutS beta is also recruited to UV-irradiated sites in nucleotide-excision-repair-and PCNA-dependent manners. Thus, MMR and its proteins function not only in replication but also in DNA repair.