DNA polymerase I acts in translesion synthesis mediated by the Y-polymerases in Bacillus subtilis
DNA polymerase I acts in translesion synthesis mediated by the Y-polymerases in Bacillus subtilis
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DOI：
10.1111/j.1365-2958.2005.04725.x
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发表时间：
2005-08-01
影响因子：
3.6
通讯作者：
Noirot-Gros, MF
中科院分区：
文献类型：
--
作者：
Duigou, S;Ehrlich, SD;Noirot-Gros, MF
跨受损DNA碱基的转座合成（TLS）最常由Y家族的普遍存在的易错DNA聚合酶进行。枯草芽孢杆菌编码两种Y-聚合酶，Pol Y1和Pol Y2，其介导TLS，分别导致自发和紫外光（UV）诱导的诱变。在这里，我们表明，TLS是一个二分的双重聚合酶过程在B。枯草芽孢杆菌，不仅涉及Y-聚合酶，而且涉及A-家族聚合酶，DNA聚合酶I（Pol 1）。自发和紫外线诱导的诱变被废除在Pol I突变体的影响，只在聚合酶催化位点。通过酵母双杂交和三杂交试验检测了Pol I和Pol Y聚合酶之间的物理相互作用，以及Pol Y1，Pol I和P-夹之间三元复合物的形成，支持TLS中A-和Y-家族聚合酶之间的功能性偶联模型。我们认为，Pol Y携带合成跨越病变，Pol I接管延长合成，直到功能性复制体恢复复制。Pol I在TLS中的关键作用揭示了A家族DNA聚合酶的新功能。
Translesion synthesis (TLS) across damaged DNA bases is most often carried out by the ubiquitous error-prone DNA polymerases of the Y-family. Bacillus subtilis encodes two Y-polymerases, Pol Y1 and Pol Y2, that mediate TLS resulting in spontaneous and ultraviolet light (UV)-induced mutagenesis respectively. Here we show that TLS is a bipartite dual polymerase process in B. subtilis, involving not only the Y-polymerases but also the A-family polymerase, DNA polymerase I (Pol 1). Both the spontaneous and the UV-induced mutagenesis are abolished in Pol I mutants affected solely in the polymerase catalytic site. Physical interactions between Pol I and either of the Pol Y polymerases, as well as formation of a ternary complex between Pol Y1, Pol I and the P-clamp, were detected by yeast two- and three-hybrid assays, supporting the model of a functional coupling between the A- and Y-family polymerases in TLS. We suggest that the Pol Y carries the synthesis across the lesion, and Pol I takes over to extend the synthesis until the functional replisome resumes replication. This key role of Pol I in TLS uncovers a new function of the A-family DNA polymerases.