Replisome-mediated Translesion Synthesis and Leading Strand Template Lesion Skipping Are Competing Bypass Mechanisms
Replisome-mediated Translesion Synthesis and Leading Strand Template Lesion Skipping Are Competing Bypass Mechanisms
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DOI：
10.1074/jbc.m114.613257
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发表时间：
2014-11-21
影响因子：
4.8
通讯作者：
Marians, Kenneth J.
中科院分区：
文献类型：
--
作者：
Gabbai, Carolina B.;Yeeles, Joseph T. P.;Marians, Kenneth J.
许多不同的酶途径已经发展，以确保DNA复制可以进行过去的模板碱基损伤。这些途径包括通过复制体的损伤跳过，复制叉退化，随后是损伤的校正和非来源依赖性复制重启或损伤下游的同源重组介导的复制重启，以及通过跨损伤合成DNA聚合酶绕过损伤。我们在这里报告的两个translesion合成聚合酶测试，只有DNA聚合酶IV，而不是DNA聚合酶II，可以从事生产性与大肠杆菌复制体绕过前导链模板损伤，尽管事实上，这两种酶被证明是相互作用的复制酶。DNA聚合酶II的3' -> 5'校正核酸外切酶的失活不能实现旁路。通过DNA聚合酶IV的旁路需要其与β钳相互作用的能力并充当跨损伤聚合酶，但不需要其“小指”结构域，即与β钳相互作用的第二区域。DNA聚合酶IV的旁路是以复制体固有的前导链损伤跳跃活性为代价的，表明它们是竞争反应。
A number of different enzymatic pathways have evolved to ensure that DNA replication can proceed past template base damage. These pathways include lesion skipping by the replisome, replication fork regression followed by either correction of the damage and origin-independent replication restart or homologous recombination-mediated restart of replication downstream of the lesion, and bypass of the damage by a translesion synthesis DNA polymerase. We report here that of two translesion synthesis polymerases tested, only DNA polymerase IV, not DNA polymerase II, could engage productively with the Escherichia coli replisome to bypass leading strand template damage, despite the fact that both enzymes are shown to be interacting with the replicase. Inactivation of the 3' -> 5' proofreading exonuclease of DNA polymerase II did not enable bypass. Bypass by DNA polymerase IV required its ability to interact with the beta clamp and act as a translesion polymerase but did not require its "little finger" domain, a secondary region of interaction with the beta clamp. Bypass by DNA polymerase IV came at the expense of the inherent leading strand lesion skipping activity of the replisome, indicating that they are competing reactions.