Mechanisms of mutation by oxidative DNA damage: reduced fidelity of mammalian DNA polymerase beta.
Mechanisms of mutation by oxidative DNA damage: reduced fidelity of mammalian DNA polymerase beta.
复制标题
DNA 氧化损伤引起的突变机制：哺乳动物 DNA 聚合酶 β 的保真度降低。
DOI：
10.1021/bi00067a040
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发表时间：
1993
期刊：
影响因子：
2.9
通讯作者：
Loeb,LA
中科院分区：
文献类型：
--
作者：
Feig,DI;Loeb,LA
1992年12月29日收到的摘要：活性氧，在细胞中产生的各种机制，损害DNA和导致突变。为了表征哺乳动物细胞中产生的突变类型，我们用哺乳动物DNA聚合酶FT复制了被活性氧损伤的DNA。双链环状M13 mp2 DNA含有一个361个核苷酸的单链缺口内的lacZ基因被损坏的有氧培养与Fe 2+和H2 O2。然后用纯化的重组大鼠DNA聚合酶0填充差距，并将DNA转染到大肠杆菌中。通过减少α-互补鉴定了0-半乳糖苷酶的非必需lacZ基因内的突变。在这个系统中，氧化损伤使靶区域内的突变频率平均增加了4.3倍。在某些地点，碱基替换率几乎是随机分布损害所预期结果的300倍。氧化诱导的突变分为两类：那些显然是由修饰DNA的直接错误编码引起的，以及那些与增强的错误掺入在preexisting聚合酶特异性热点相关的。后一组可能是由于氧化修饰引起的DNA构象变化，可能是一种新的诱变机制的指示。在原核和真核细胞中，氧通过一系列单电子还原代谢，产生各种氧自由基和相关物种。这些高活性中间体改变细胞大分子。艾姆斯及其同事已经估计了人细胞中活性氧物质对DNA损伤的程度（Shigenaga等人，1989; Cathacart等人，1984; Richter等人，1988年）。基于8-氧代鸟嘌呤的回收（Shigenaga等人，
Revised Manuscript Received December 29, 1992 abstract: Reactive oxygen species, produced in cells by a variety of mechanisms, damage DNA and cause mutations. To characterize the types of mutations produced in mammalian cells, we copied DNA damaged by reactive oxygen species with mammalian DNA polymerase ft. Double-stranded circular M13mp2 DNA containing a 361-nucleotide single-stranded gap within the lacZ gene was damaged by aerobic incubation with Fe2+ and H2O2. The gap then was filled by purified recombinant rat DNA polymerase 0, and the DNA was transfected into Escherichia coli. Mutations within the nonessential lacZ gene for 0-galactosidase were identified by reduced a-complementation. In this system, oxidative damage increased the mutation frequency within the target region by an average of 4.3-fold. At certain sites, the base substitution rate is nearly 300 times greater than would be expected to resultfrom a random distribution of damage. The oxidatively induced mutations fall into two categories: those apparently caused by direct miscoding of modified DNA and those associated with enhanced misincorporation at prexisting polymerase-specific hot spots. The latter group may be due to a conformational change in the DNA caused by oxidative modification and could be indicative of a novel mutagenic mechanism.In procaryotic and eucaryotic cells, oxygen is metabolized by a series of one-electron reductions, generating a variety of oxygen free radicals and associated species. These highly reactive intermediates alter cellular macromolecules. The extent of DNA damage by reactive oxygen species in human cells has been estimated by Ames and co-workers (Shigenaga et al., 1989; Cathacart et al., 1984; Richter et al., 1988). On the basis of the recovery of 8-oxoguanine (Shigenaga et al.,