Proliferating cell nuclear antigen promotes translesion synthesis by DNA polymerase ζ
Proliferating cell nuclear antigen promotes translesion synthesis by DNA polymerase ζ
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DOI：
10.1074/jbc.c500173200
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发表时间：
2005-06-24
影响因子：
4.8
通讯作者：
Burgers, PMJ
中科院分区：
文献类型：
--
作者：
Garg, P;Stith, CM;Burgers, PMJ
DNA聚合酶ζ（Pol ζ）是Rev3和Rev7组成的异二聚体，对真核生物中由DNA损伤引发的诱变至关重要。已表明与复制夹增殖细胞核抗原（PCNA）形成持续合成复合物的DNA聚合酶与共有PCNA结合基序QxxLxxFF高度匹配。Pol ζ的任一亚基都缺乏这种共有基序，但其活性受PCNA刺激。特别是，PCNA极大地刺激了含紫外线损伤的DNA的跨损伤合成，使得跨损伤合成速率与Pol ζ在未损伤DNA上的复制速率相当。PCNA还刺激了Pol ζ对一个无碱基位点模型的跨损伤合成。有效的PCNA刺激要求通过使用生物素 - 链霉亲和素阻挡物或其他阻断物来防止PCNA从含损伤的模型寡核苷酸模板 - 引物上滑落。在这些实验条件下，DNA聚合酶δ或η（Rad30）也能检测到对无碱基位点的轻松绕过。由Rad17、Mec3和Ddc1组成的酵母DNA损伤检查点夹（人类9 - 1 - 1的同源物）与损伤诱导的诱变有关。然而，这个检查点夹并没有刺激Pol ζ或DNA聚合酶δ的跨损伤合成。
DNA polymerase zeta (Pol zeta), a heterodimer of Rev3 and Rev7, is essential for DNA damage provoked mutagenesis in eukaryotes. DNA polymerases that function in a processive complex with the replication clamp proliferating cell nuclear antigen ( PCNA) have been shown to possess a close match to the consensus PCNA-binding motif QxxLxxFF. This consensus motif is lacking in either subunit of Pol zeta, yet its activity is stimulated by PCNA. In particular, translesion synthesis of UV damage-containing DNA is dramatically stimulated by PCNA such that translesion synthesis rates are comparable with replication rates by Pol zeta on undamaged DNA. PCNA also stimulated translesion synthesis of a model abasic site by Pol zeta. Efficient PCNA stimulation required that PCNA was prevented from sliding off the damage-containing model oligonucleotide template-primer through the use of biotin-streptavidin bumpers or other blocks. Under those experimental conditions, facile bypass of the abasic site was also detected by DNA polymerase delta or eta (Rad30). The yeast DNA damage checkpoint clamp, consisting of Rad17, Mec3, and Ddc1, and an ortholog of human 9-1-1, has been implicated in damage-induced mutagenesis. However, this checkpoint clamp did not stimulate translesion synthesis by Pol zeta or by DNA polymerase delta.