Proliferating cell nuclear antigen and Msh2p-Msh6p interact to form an active mispair recognition complex
Proliferating cell nuclear antigen and Msh2p-Msh6p interact to form an active mispair recognition complex
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DOI：
10.1038/81708
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发表时间：
2000-11-01
期刊：
影响因子：
30.8
通讯作者：
Kolodner, RD
中科院分区：
文献类型：
--
作者：
Flores-Rozas, H;Clark, D;Kolodner, RD
增殖细胞核抗原（PCNA）是错配修复（MMR）所必需的，并且已显示与含有Msh 2 p或MLH 1的复合物相互作用（参考文献1-4）。尽管PCNA在MMR早期作用的生物化学基础尚不清楚，但PCNA在DNA合成步骤之前和期间在MMR中起作用（1，3，5）。在这里，我们观察到之间的相互作用PCNA和Msh 2 p-Msh 6p介导的一个特定的PCNA结合位点存在于Msh 6p。一个msh 6突变，消除了PCNA结合位点引起的增变表型和缺陷的相互作用与PCNA。PCNA与Msh 2 p-Msh 6p的结合促进了Msh 2 p-Msh 6p与含有错配碱基的DNA的优先结合。由MMR缺陷型pol 30等位基因编码的突变型PCNA蛋白与Msh 2 p-Msh 6p的相互作用和刺激Msh 2 p-Msh 6p的错配结合是缺陷的。我们的研究结果表明，PCNA的功能直接在错配识别，错配识别需要一个更高的顺序复杂的蛋白质，除了Msh 2 p-Msh 6p。
Proliferating cell nuclear antigen (PCNA) is required for mismatch repair (MMR) and has been shown to interact with complexes containing Msh2p or MLH1 (refs 1-4). PCNA has been implicated to act in MMR before and during the DNA synthesis step, although the biochemical basis for the role of PCNA early in MMR is unclear(1,3,5). Here we observe an interaction between PCNA and Msh2p-Msh6p mediated by a specific PCNA-binding site present in Msh6p. An msh6 mutation that eliminated the PCNA-binding site caused a mutator phenotype and a defect in the interaction with PCNA. The association of PCNA with Msh2p-Msh6p stimulated the preferential binding of Msh2p-Msh6p to DNA containing mispaired bases. Mutant PCNA proteins encoded by MMR-defective pol30 alleles were defective for interaction with Msh2p-Msh6p and for stimulation of mispair binding by Msh2p-Msh6p. Our results suggest that PCNA functions directly in mispair recognition and that mispair recognition requires a higher-order complex containing proteins in addition to Msh2p-Msh6p.