Analysis of hMLH1 missense mutations in East Asian patients with suspected hereditary nonpolyposis colorectal cancer
Analysis of hMLH1 missense mutations in East Asian patients with suspected hereditary nonpolyposis colorectal cancer
复制标题
东亚疑似遗传性非息肉病性结直肠癌患者 hMLH1 错义突变分析
DOI：
10.1158/1078-0432.ccr-07-1028
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发表时间：
2007-12-15
影响因子：
11.5
通讯作者：
Wang, Yaping
中科院分区：
文献类型：
--
作者：
Fan, Yimei;Wang, Wei;Wang, Yaping
目的：DNA错配修复基因hMLH1的种系突变是遗传性非息肉病性结直肠癌的常见原因，其中约三分之一是错义突变。在东亚疑似遗传性非息肉病性结直肠癌患者中经常检测到hMLH1的几种错义突变，但其致病作用尚未得到广泛评估。本研究的目的是对这些变异及其与东亚胃肠道癌症的关系进行功能分析。实验设计：采用酵母双杂交和共免疫沉淀法对10个hMLH1变异进行分析。结果：hMLH1的羧基末端替换Q542L、L549P、L574P和P581L在酵母双杂交和共免疫沉淀试验中导致活性完全丧失，因此可能被认为是致病的。在共免疫沉淀中，氨基末端变异S46I、G65D、G67R和R217C不影响与hPMS2的复合物形成，但在酵母双杂交实验中部分或完全丧失了活性，我们认为这些变异可能降低了异源二聚体进入细胞核的效率，从而可能阻断或降低错配修复功能。V384D和Q701K变异导致hMLH1与hPMS2的相互作用效率降低，并可能增加突变携带者的胃肠道癌风险。结论：这项工作有效地评估了一些先前未确定的hMLH1基因错义突变的功能后果，可能对遗传性胃肠道癌的临床诊断有用，特别是在东亚人。
Purpose: Germ line mutations in the DNA mismatch repair gene hMLH1 are a frequent cause of hereditary nonpolyposis colorectal cancer and about one-third of these are missense mutations. Several missense mutations in hMLH1 have frequently been detected in East Asian patients with suspected hereditary nonpolyposis colorectal cancer, but their pathogenic role has not been extensively assessed. The aim of this study was to perform functional analyses of these variants and their association with gastrointestinal cancer in East Asians.Experimental Design: Altogether, 10 hMLH1 variants were analyzed by yeast two-hybrid and coimmunoprecipitation assays.Results: The carboxyl-terminal replacements Q542L, L549P, L574P, and P581L in hMLH1 resulted in complete loss of activity in both yeast two-hybrid and coimmunoprecipitation tests and thus might be considered as pathogenic. The amino-terminal variants S46I, G65D, G67R, and R217C did not affect complex formation with hPMS2 in coimmunoprecipitation, but partly or fully lost their activity in yeast two-hybrid assay, and we suggested that these variants might reduce the efficiency of the heterodimer to go into the nucleus and thus the mismatch repair function might be blocked or reduced. The V384D and the Q701K variant resulted in the interaction of hMLH1 with hPMS2 at reduced efficiency and might raise the gastrointestinal cancer risk of the mutation carriers.Conclusions: This work availably evaluated the functional consequences of some missense mutations not previously determined in the hMLH1 gene and might be useful for the clinical diagnosis of hereditary gastrointestinal cancer, especially in East Asians.