Site-specific excision repair of 1-nitrosopyrene-induced DNA adducts at the nucleotide level in the HPRT gene of human fibroblasts: effect of adduct conformation on the pattern of site-specific repair.
Site-specific excision repair of 1-nitrosopyrene-induced DNA adducts at the nucleotide level in the HPRT gene of human fibroblasts: effect of adduct conformation on the pattern of site-specific repair.
复制标题
人成纤维细胞 HPRT 基因核苷酸水平上 1-亚硝基芘诱导的 DNA 加合物的位点特异性切除修复：加合物构象对位点特异性修复模式的影响。
DOI：
10.1128/mcb.16.7.3714
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发表时间：
1996
影响因子：
5.3
通讯作者：
McCormick,JJ
中科院分区：
文献类型：
--
作者：
Wei,D;Maher,VM;McCormick,JJ
研究表明，不同类型的 DNA 加合物在人体细胞中以不同的速率修复，这表明 DNA 加合物构象是核苷酸切除修复速率的主要决定因素。然而，最近对正常人成纤维细胞 DNA 中环丁烷嘧啶二聚体或苯并[a]芘二醇环氧化物 (BPDE) 诱导的加合物在核苷酸水平上的修复的研究表明，同一加合物在不同核苷酸位置的修复率可能相差高达 10 倍，这表明局部 DNA 构象的重要作用。为了了解位点特异性 DNA 修复是否是大体积 DNA 加合物的常见现象，我们使用连接介导的 PCR 在核苷酸水平上测定了次黄嘌呤磷酸核糖基转移酶基因外显子 3 中 1-亚硝基芘 (1-NOP) 诱导的加合物的修复率。为了区分加合物构象和局部 DNA 构象对修复率的贡献，我们将使用 1-NOP 获得的结果与之前使用 BPDE 获得的结果进行了比较。任一试剂形成的主要 DNA 加合物都涉及鸟嘌呤。我们发现 1-NOP 诱导的加合物的修复率在核苷酸水平上也存在显着差异，但在 DNA 同一区域的相同鸟嘌呤位置上，位点特异性修复模式与 BPDE 诱导的加合物不同。外显子 3 中 1-NOP 加合物的平均切除修复速率比 BPDE 加合物快两到三倍，但在特定核苷酸处，该速率比 BPDE 加合物慢或快，或者在某些情况下等于 BPDE 加合物。这些结果表明，局部 DNA 构象对特定核苷酸位置修复速率的贡献取决于所涉及的特定 DNA 加合物。然而，数据还表明，DNA 加合物的构象并不是影响不同核苷酸位置修复率的唯一因素。相反，特定核苷酸位置的修复速率取决于特定加合物构象与该核苷酸的局部 DNA 构象之间的相互作用。
Studies showing that different types of DNA adducts are repaired in human cells at different rates suggest that DNA adduct conformation is the major determinant of the rate of nucleotide excision repair. However, recent studies of repair of cyclobutane pyrimidine dimers or benzo[a]pyrene diol epoxide (BPDE)-induced adducts at the nucleotide level in DNA of normal human fibroblasts indicate that the rate of repair of the same adduct at different nucleotide positions can vary up to 10-fold, suggesting an important role for local DNA conformation. To see if site-specific DNA repair is a common phenomenon for bulky DNA adducts, we determined the rate of repair of 1-nitrosopyrene (1-NOP)-induced adducts in exon 3 of the hypoxanthine phosphoribosyltransferase gene at the nucleotide level using ligation-mediated PCR. To distinguish between the contributions of adduct conformation and local DNA conformation to the rate of repair, we compared the results obtained with 1-NOP with those we obtained previously using BPDE. The principal DNA adduct formed by either agent involves guanine. We found that rates of repair of 1-NOP-induced adducts also varied significantly at the nucleotide level, but the pattern of site-specific repair differed from that of BPDE-induced adducts at the same guanine positions in the same region of DNA. The average rate of excision repair of 1-NOP adducts in exon 3 was two to three times faster than that of BPDE adducts, but at particular nucleotides the rate was slower or faster than that of BPDE adducts or, in some cases, equal to that of BPDE adducts. These results indicate that the contribution of the local DNA conformation to the rate of repair at a particular nucleotide position depends upon the specific DNA adduct involved. However, the data also indicate that the conformation of the DNA adduct is not the only factor contributing to the rate of repair at different nucleotide positions. Instead, the rate of repair at a particular nucleotide position depends on the interaction between the specific adduct conformation and the local DNA conformation at that nucleotide.