Responses to the Major Acrolein-derived Deoxyguanosine Adduct inEscherichia coli *
Responses to the Major Acrolein-derived Deoxyguanosine Adduct inEscherichia coli *
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DOI：
10.1074/jbc.m008918200
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发表时间：
2001-03
期刊：
影响因子：
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通讯作者：
I. Yang;Munfarah Hossain;H. Miller;Sonia Khullar;F. Johnson;A. Grollman;M. Moriya
中科院分区：
文献类型：
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作者：
I. Yang;Munfarah Hossain;H. Miller;Sonia Khullar;F. Johnson;A. Grollman;M. Moriya
丙烯醛是一种在环境中普遍存在的反应性脱氧核糖核酸不饱和醛，在哺乳动物细胞中以内源形式形成，它与脱氧核糖核酸反应生成外环α，β加合物，γ(DNAOHPDG)。γ-OH-PDG的细胞加工和诱变潜力已经被用一种位点特异性的方法来检测，在这种方法中，一个加合物被嵌入到双链质粒DNA中。对后代质粒的分析表明，该加合物是通过核苷酸切除修复而被切除的。抑制∼合成的表观水平为Δ的70%。依赖于recA的重组修复可以部分克服DNA合成的障碍。靶向G-→T颠换的频率为7×10-−-4/跨损合成。编码“SOS”DNA聚合酶的polB、dinB和umuD、C基因的失活对跨损伤合成的效率和保真度没有显著影响。在试管引子延伸实验中发现，聚合酶I的Klenow片段催化容易出错的合成，优先结合DAMP和dGMP而不是γ-OH-PDG。我们从这项研究中得出结论，DNA聚合酶III以一种无错误的方式催化跨γ-OH-PDG的跨损伤合成。核苷酸切除修复、重组修复和高精度的跨损伤合成相结合，保护大肠杆菌免受这种DNA加合物的潜在遗传毒性。
Acrolein, a reactive α,β-unsaturated aldehyde found ubiquitously in the environment and formed endogenously in mammalian cells, reacts with DNA to form an exocyclic DNA adduct, 3H-8-hydroxy-3-(β-d-2′-deoxyribofuranosyl)-5,6,7,8-tetrahydropyrido[3,2-a]purine-9-one (γ-OH-PdG). The cellular processing and mutagenic potential of γ-OH-PdG have been examined, using a site-specific approach in which a single adduct is embedded in double-strand plasmid DNA. Analysis of progeny plasmid reveals that this adduct is excised by nucleotide excision repair. The apparent level of inhibition of DNA synthesis is ∼70% in Escherichia coli ΔrecA, uvrA. The block to DNA synthesis can be overcome partially byrecA-dependent recombination repair. Targeted G → T transversions were observed at a frequency of 7 × 10−4/translesion synthesis. Inactivation ofpolB, dinB, and umuD,C genes coding for “SOS” DNA polymerases did not affect significantly the efficiency or fidelity of translesion synthesis. In vitroprimer extension experiments revealed that the Klenow fragment of polymerase I catalyzes error-prone synthesis, preferentially incorporating dAMP and dGMP opposite γ-OH-PdG. We conclude from this study that DNA polymerase III catalyzes translesion synthesis across γ-OH-PdG in an error-free manner. Nucleotide excision repair, recombination repair, and highly accurate translesion synthesis combine to protect E. coli from the potential genotoxicity of this DNA adduct.