Contiguous 2,2,4-triamino-5(2H)-oxazolone obstructs DNA synthesis by DNA polymerases α, β, η, ι, κ, REV1 and Klenow Fragment exo-, but not by DNA polymerase ζ.
Contiguous 2,2,4-triamino-5(2H)-oxazolone obstructs DNA synthesis by DNA polymerases α, β, η, ι, κ, REV1 and Klenow Fragment exo-, but not by DNA polymerase ζ.
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DOI：
10.1093/jb/mvv103
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发表时间：
2016-03
影响因子：
2.7
通讯作者：
Miyazawa H
中科院分区：
文献类型：
--
作者：
Suzuki M;Kino K;Kawada T;Oyoshi T;Morikawa M;Kobayashi T;Miyazawa H
鸟嘌呤是四种DNA碱基中最容易氧化的，并且序列中的连续鸟嘌呤（GG）比序列中的单个鸟嘌呤更容易氧化。GG的持续氧化导致连续的氧化鸟嘌呤损伤。在GG氧化后检测到两个连续的2，5-二氨基-4H-咪唑-4-酮（鸟嘌呤的氧化形式，水解为2，2，4-三氨基-5（2 H）-恶唑酮（Oz））。在这项研究中，我们使用Klenow片段exo−（KF exo−）和DNA聚合酶（Pos）α，β，ε，η，ι，κ和REV 1分析了两个连续Oz分子（OzOz）的跨损伤合成（TLS）。我们发现KF exo−和Pos α、β、i和REV 1在OzOz的3′ Oz对面插入一个核苷酸，并在随后的延伸处停滞，而Pol κ没有掺入核苷酸。Pol η只能低效地将引物延伸至OzOz的全长;大多数DNA链的合成在OzOz的3′或5′ Oz处停滞。然而，令人惊讶的是，与其他DNA聚合酶不同，Pol-1能有效地将引物延伸至OzOz的全长，但催化了易于出错的核苷酸掺入。因此，我们认为，有效的臭氧TLS所需的Pol。这些结果表明，OzOz阻碍DNA聚合酶的DNA合成，除了Polo。
Guanine is the most easily oxidized of the four DNA bases, and contiguous guanines (GG) in a sequence are more readily oxidized than a single guanine in a sequence. Continued oxidation of GGs results in a contiguous oxidized guanine lesion. Two contiguous 2,5-diamino-4H-imidazol-4-ones, an oxidized form of guanine that hydrolyses to 2,2,4-triamino-5(2H)-oxazolone (Oz), are detected following the oxidation of GG. In this study, we analysed translesion synthesis (TLS) across two contiguous Oz molecules (OzOz) using Klenow Fragment exo− (KF exo−) and DNA polymerases (Pols) α, β, ζ, η, ι, κ and REV1. We found that KF exo− and Pols α, β, ι and REV1 inserted one nucleotide opposite the 3′ Oz of OzOz and stalled at the subsequent extension, and that Pol κ incorporated no nucleotide. Pol η only inefficiently elongated the primer up to full-length across OzOz; the synthesis of most DNA strands stalled at the 3′ or 5′ Oz of OzOz. Surprisingly, however, Pol ζ efficiently extended the primer up to full-length across OzOz, unlike the other DNA polymerases, but catalysed error-prone nucleotide incorporation. We therefore believe that Pol ζ is required for efficient TLS of OzOz. These results show that OzOz obstructs DNA synthesis by DNA polymerases except Pol ζ.