Simultaneous Disruption of Two DNA Polymerases, Polη and Polζ, in Avian DT40 Cells Unmasks the Role of Polη in Cellular Response to Various DNA Lesions
Simultaneous Disruption of Two DNA Polymerases, Polη and Polζ, in Avian DT40 Cells Unmasks the Role of Polη in Cellular Response to Various DNA Lesions
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DOI：
10.1371/journal.pgen.1001151
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发表时间：
2010-10-01
期刊：
影响因子：
4.5
通讯作者：
Takeda, Shunichi
中科院分区：
文献类型：
--
作者：
Hirota, Kouji;Sonoda, Eiichiro;Takeda, Shunichi
复制性DNA聚合酶经常因DNA损伤而停滞。由此产生的复制阻塞通过同源重组（HR）和翻译DNA合成（TLS）释放。TLS使用特殊的TLS聚合酶绕过DNA损伤。我们通过从鸡DT40细胞系中产生POL eta(-/-) /POL zeta（-/-）细胞，提供了DNA聚合酶eta（以癌症易感性疾病着色性干皮病（XP-V）的变异形式突变）与DNA聚合酶zeta之间合作的显著体内证据。POL zeta（-/-）细胞对非常广泛的DNA损伤剂高度敏感，而XP-V细胞仅在存在咖啡因处理的情况下对紫外线（UV）表现出中等敏感性，对任何其他损伤剂均无明显敏感性。因此，人们普遍认为Pol - eta在细胞对紫外线诱导的DNA损伤的耐受中起着非常特殊的作用。我们提出的证据挑战了这一假设。对POL eta(-/-) /POL zeta（-/-）细胞的表型分析表明，POL eta的缺失出乎意料地显著挽救了POL zeta（-/-）细胞的所有突变表型，并通过包括HR在内的备份途径恢复了DNA损伤耐受能力。综上所述，Pol eta对TLS事件的影响比XP-V细胞表型预测的要大得多。
Replicative DNA polymerases are frequently stalled by DNA lesions. The resulting replication blockage is released by homologous recombination (HR) and translesion DNA synthesis (TLS). TLS employs specialized TLS polymerases to bypass DNA lesions. We provide striking in vivo evidence of the cooperation between DNA polymerase eta, which is mutated in the variant form of the cancer predisposition disorder xeroderma pigmentosum (XP-V), and DNA polymerase zeta by generating POL eta(-/-) /POL zeta(-/-) cells from the chicken DT40 cell line. POL zeta(-/-) cells are hypersensitive to a very wide range of DNA damaging agents, whereas XP-V cells exhibit moderate sensitivity to ultraviolet light (UV) only in the presence of caffeine treatment and exhibit no significant sensitivity to any other damaging agents. It is therefore widely believed that Pol eta plays a very specific role in cellular tolerance to UV-induced DNA damage. The evidence we present challenges this assumption. The phenotypic analysis of POL eta(-/-) /POL zeta(-/-) cells shows that, unexpectedly, the loss of Pol eta significantly rescued all mutant phenotypes of POL zeta(-/-) cells and results in the restoration of the DNA damage tolerance by a backup pathway including HR. Taken together, Pol eta contributes to a much wide range of TLS events than had been predicted by the phenotype of XP-V cells.