MISREADING OF DNA TEMPLATES CONTAINING 8-HYDROXYDEOXYGUANOSINE AT THE MODIFIED BASE AND AT ADJACENT RESIDUES
MISREADING OF DNA TEMPLATES CONTAINING 8-HYDROXYDEOXYGUANOSINE AT THE MODIFIED BASE AND AT ADJACENT RESIDUES
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DOI：
10.1038/327077a0
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发表时间：
1987-05-07
期刊：
影响因子：
64.8
通讯作者：
NISHIMURA, S
中科院分区：
文献类型：
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作者：
KUCHINO, Y;MORI, F;NISHIMURA, S
以往的研究表明，DNA中的脱氧鸟苷残基在体外和体内都会被各种产生氧自由基的试剂(如还原试剂O2、金属离子O2、多氯酚-H_2O_2-Fe3+、石棉-H_2O_2或电离辐射1-5)在体内C-8位羟基化生成8-羟基脱氧鸟苷(8-OH-DG)。这些试剂大多是致突变或致癌的，因此，8-OH-DG的形成也可以被认为是氧自由基致突变或致癌的可能原因。人们有兴趣知道DNA中的8-OH-DG残基在DNA复制过程中是否被误读。为了回答这个问题，我们利用大肠杆菌DNA聚合酶I(Klenow片段)的DNA合成系统，研究了DNA中8-OH-DG残基对DNA复制保真度的影响。合成的寡核苷酸，在特定的位置上有或没有8-OH-dG残基，被化学合成，并在双脱氧链末端测序法的条件下作为DNA合成的模板。令人惊讶的是，除了8-OH-DG残基本身的误读外，8-OH-DG残基(G尚未被检测)旁边的嘧啶也被误读了。
It has been shown previously that deoxyguanosine residues in DNA are hydroxylated at the C-8 position bothin vitroandin vivoto produce 8-hydroxydeoxyguanosine (8-OH-dG) by various agents that produce oxygen radicals such as reducing reagents-O2, metal ions-O2, poryphenol-H2O2-Fe3+, asbestos-H2O2or ionizing radi-ation1–5. These agents are mostly either mutagenic or carcinogenic; therefore, the formation of 8-OH-dG can also be considered a likely cause of mutation or carcinogenesis by oxygen radicals. It is of interest to know whether the 8-OH-dG residue in DNA is misread during DNA replication. To answer this question, we have examined the effect of the 8-OH-dG residue in DNA on the fidelity of DNA replication using a DNA synthesis systemin vitrowithEscherichia coliDNA polymerase I (Klenow fragment). The syn-thetic oligodeoxynucleotides, with or without an 8-OH-dG residue in a specified position, were chemically synthesized and used as templates for DNA synthesis under the conditions of the dideoxy chain termination sequencing method. Surprisingly, in addition to misreading of the 8-OH-dG residue itself, pyrimidines next to the 8-OH-dG residue (G has not yet been tested) were also misread.