Error-Prone Translesion DNA Synthesis by Escherichia coli DNA Polymerase IV (DinB) on Templates Containing 1,2-dihydro-2-oxoadenine.
Error-Prone Translesion DNA Synthesis by Escherichia coli DNA Polymerase IV (DinB) on Templates Containing 1,2-dihydro-2-oxoadenine.
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DOI：
10.4061/2010/807579
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发表时间：
2010-09-26
影响因子：
2.3
通讯作者：
Zhang-Akiyama QM
中科院分区：
文献类型：
--
作者：
Hori M;Yonekura S;Nohmi T;Gruz P;Sugiyama H;Yonei S;Zhang-Akiyama QM
大肠杆菌 DNA 聚合酶 IV (Pol IV) 参与 DNA 中受损碱基的旁路复制。活性氧 (ROS) 在正常新陈代谢过程中以及由于电离辐射等外源应激而不断产生。 ROS 会诱导 DNA 中各种碱基损伤。检查 Pol IV 是否能够绕过氧化损伤的碱基非常重要。在本研究中，重组 Pol IV 与含有胸腺嘧啶乙二醇 (dTg)、5-甲酰尿嘧啶 (5-fodU)、5-羟甲基尿嘧啶 (5-hmdU)、7,8-二氢-8-氧代鸟嘌呤 (8-oxodG) 和 1,2-二氢-2-氧代腺嘌呤 (2-oxodA) 的寡核苷酸一起孵育。引物延伸测定表明，Pol IV 更倾向于在 5-fodU 和 5-hmdU 对面插入 dATP，而在 dTg 对面插入核苷酸则效率较低。 Pol IV在8-oxodG对面插入dCTP和dATP，但能力较低。它插入 dCTP 比插入 2-oxodA 的 dTTP 更有效。 Pol IV 绕过这些病变的能力按以下顺序下降：2-oxodA > 5-fodU~5-hmdU > 8-oxodG > dTg。事实上，Pol IV 更倾向于在 2-oxodA 对面插入 dCTP，这表明 2-oxodA 具有导致 A:T→G:C 转变的诱变潜力。过氧化氢导致大肠杆菌中 A:T→G:C 突变增加约 2 倍，而在过表达 Pol IV 的大肠杆菌中这种增加显着更大。这些结果表明 Pol IV 可能参与 ROS 增强的 A:T→G:C 突变。
Escherichia coli DNA polymerase IV (Pol IV) is involved in bypass replication of damaged bases in DNA. Reactive oxygen species (ROS) are generated continuously during normal metabolism and as a result of exogenous stress such as ionizing radiation. ROS induce various kinds of base damage in DNA. It is important to examine whether Pol IV is able to bypass oxidatively damaged bases. In this study, recombinant Pol IV was incubated with oligonucleotides containing thymine glycol (dTg), 5-formyluracil (5-fodU), 5-hydroxymethyluracil (5-hmdU), 7,8-dihydro-8-oxoguanine (8-oxodG) and 1,2-dihydro-2-oxoadenine (2-oxodA). Primer extension assays revealed that Pol IV preferred to insert dATP opposite 5-fodU and 5-hmdU, while it inefficiently inserted nucleotides opposite dTg. Pol IV inserted dCTP and dATP opposite 8-oxodG, while the ability was low. It inserted dCTP more effectively than dTTP opposite 2-oxodA. Pol IV's ability to bypass these lesions decreased in the order: 2-oxodA > 5-fodU~5-hmdU > 8-oxodG > dTg. The fact that Pol IV preferred to insert dCTP opposite 2-oxodA suggests the mutagenic potential of 2-oxodA leading to A:T→G:C transitions. Hydrogen peroxide caused an ~2-fold increase in A:T→G:C mutations in E. coli, while the increase was significantly greater in E. coli overexpressing Pol IV. These results indicate that Pol IV may be involved in ROS-enhanced A:T→G:C mutations.