胃癌组织中DNA聚合酶β基因突变特点分析  

Mutation characteristics of DNA polymerase beta gene in human gastric carcinoma tissue

作　　者：赵洁 董子明[2] 毛海洲 王煊 赵国强[2] 

机构地区：[1]济南军区第155中心医院消化内科,河南开封475003 [2]郑州大学基础医学院病理生理教研室,河南郑州450052

出　　处：《第四军医大学学报》2005年第21期1930-1931,共2页Journal of the Fourth Military Medical University

基　　金：国家自然科学基金(39870287)

摘　　要：目的:探讨人胃癌DNA聚合酶β(polβ)基因突变的特点.方法:对32例人胃癌组织及32例正常对照组织中提取总RNA,进行RT-PCR,SSCP,对PCR产物克隆后以Sanger s法测序,并采用Omiga及Dansis软件分析结果.结果:人胃癌标本的polβ基因突变率21.9%.测序分析了7例SSCP异常中的3例,其突变分别为196位A→G,268位A→G,790位A→T;经OMIGA软件分析,这3个polβ的点突变均导致了氨基酸的改变,具体形式为:核酸196位A→G导致氨基酸28位Asn→Ser;核酸268位A→G导致氨基酸52位Lys→Arg;核酸790位A→T导致氨基酸226位Asp→Val.DNASIS软件Chou-fasman算法推测,polβ的196位A→G突变可以导致polβ酶蛋白的二级结构图明显改变.结论:人胃癌组织polβ基因突变率达21.9%;这3个polβ的点突变都导致了氨基酸的改变,196位A→G突变可以导致polβ酶蛋白的二级结构明显改变.AIM： To detect the mutation characteristics of DNA polymerase beta gene （polβ gene） in human gastric carcinoma. METHODS： Total RNA was extracted from 32 gastric cancer samples and 32 tissue samples adjacent to tumors. The RT-PCR was carried out and the PCR product was cloned and sequenced with Sanger＇s method subsequently. RESULTS： Three from the seven abnormal SSCP samples were sequenced and the mutation sites were： site 196 A→G, site 268 A→G and site 790 A→T. No mutation was found by sequencing in a normal PCR-SSCP sample of the tissues adjacent to the tumor. Omiga analysis showed that the three point mutations led to changes of amino acid： site 196 A→G of nucleic acid resulted in site 28 Asn→Ser of amino acid, site 268 A→G of nucleic acid resulted in site 52 Lys→Arg of amino acid, and site 790 A→T of nucleic acid resulted in site 226 Asp→Val of amino acid. Chou-fasman method of Dnasis showed that site 196 A→ G mutation caused great changes in the secondary structure of polβenzyme. CONCLUSION： The polβgene mutation rate is up to 21.9%. The three point mutations observed in this study all lead to the alternation of amino acid. Site 196 A→ G mutation can cause great changes in the secondary structure of polβ enzyme.

关 键 词：DNA聚合酶Β 基因突变 胃肿瘤 

分 类 号：R735.2[医药卫生—肿瘤]