trans-lesion synthesis past bulky benzo[a]pyrene diol epoxide N2-dG and N6-dA lesions catalyzed by DNA bypass polymerases
trans-lesion synthesis past bulky benzo[a]pyrene diol epoxide N2-dG and N6-dA lesions catalyzed by DNA bypass polymerases
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DOI：
10.1074/jbc.m201167200
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发表时间：
2002-08-23
影响因子：
4.8
通讯作者：
Geacintov, NE
中科院分区：
文献类型：
--
作者：
Rechkoblit, O;Zhang, YB;Geacintov, NE
在体外研究了由人旁路DNA聚合酶kappa（hDinB 1）、pol eta（hRad 30 A）、pol iota（hRad 30 B）和酵母pol zeta（Rev 3和Rev 7）在位点特异性修饰的模板寡核苷酸链中催化的体外引物延伸反应的有效性。模板含有单一的大块损伤，其来源于r7，t8-二羟基-t9，10-环氧-7，8，9，10-四氢苯并[a]芘（环境致癌物苯并[a]芘的代谢物）的致突变（+）-或（-）-对映异构体反式加成至寡核苷酸模板中鸟嘌呤或腺嘌呤的环外氨基，长度为33个或更多个碱基。在“运行启动”引物延伸反应中，pol kappa有效地绕过了立体异构的（+）-和（-）-反式鸟嘌呤加合物，但没有绕过类似的腺嘌呤加合物。与此形成鲜明对比的是，与pol kappa（两者都属于Y家族聚合酶）具有相当大的序列同源性的pol eta被鸟嘌呤加合物和（-）-反式腺嘌呤加合物部分阻断，尽管立体异构的（+）-反式腺嘌呤加合物更成功地被绕过。无论是pol iota还是pol zeta，单独或组合，在相同加合物的跨损伤合成中都是无效的。在所有情况下，插入的保真度取决于加合物的立体化学和结构。一般来说，无错误的核苷酸插入相对的病变往往更依赖于加合物立体化学比易错插入。所测试的聚合酶中没有一种是用于来自抗BPDE的立体异构体大体积多环芳烃-DNA加合物的通用旁路聚合酶。
The effectiveness of in vitro primer elongation reactions catalyzed by human bypass DNA polymerases kappa (hDinB1), pol eta (hRad30A), pol iota (hRad30B), and yeast pol zeta (Rev3 and Rev7) in site-specifically modified template oligonucleotide strands were studied in vitro. The templates contained single bulky lesions derived from the trans-addition of the mutagenic (+)- or (-)-enantiomers of r7,t8-dihydroxy-t9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (a metabolite of the environmental carcinogen benzo[a]pyrene), to the exocyclic amino groups of guanine or adenine in oligonucleotide templates 33, or more, bases long. In "running start" primer extension reactions, pol kappa effectively bypassed both the stereoisomeric (+)- and (-)-trans-guanine adducts but not the analogous adenine adducts. In sharp contrast, pol eta, which exhibits considerable sequence homology with pol kappa (both belong to the group of Y family polymerases), is partially blocked by the guanine adducts and the (-)-trans-adenine adduct, although the stereoisomeric (+)-trans-adenine adduct is more successfully bypassed. Neither pol iota nor pol zeta, either alone or in combination, were effective in trans-lesion synthesis past the same adducts. In all cases, the fidelity of insertion is dependent on adduct stereochemistry and structure. Generally, error-free nucleotide insertion opposite the lesions tends to depend more on adduct stereochemistry than error-prone insertion. None of the polymerases tested are a universal bypass polymerase for the stereoisomeric bulky polycyclic aromatic hydrocarbon-DNA adducts derived from anti-BPDE.