The Werner syndrome protein operates in base excision repair and cooperates with DNA polymerase beta.
The Werner syndrome protein operates in base excision repair and cooperates with DNA polymerase beta.
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DOI：
10.1093/nar/gkj475
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发表时间：
2006
影响因子：
14.9
通讯作者：
Bohr VA
中科院分区：
文献类型：
--
作者：
Harrigan JA;Wilson DM 3rd;Prasad R;Opresko PL;Beck G;May A;Wilson SH;Bohr VA
基因组不稳定是癌症和衰老的一个特征，也是早老性疾病沃纳综合征（WS）的一个标志。有证据表明，Werner综合征蛋白（WRN）通过参与DNA修复来维持基因组完整性。特别是，生化证据表明WRN在碱基切除修复（BER）中起作用。我们之前报道过WRN解旋酶活性刺激DNA聚合酶β (pol β)链位移合成。在本报告中，我们证明了WRN外切酶活性可以与pol β协同作用，pol β是一种缺乏3 ‘ -5 ’校对活性的聚合酶。此外，利用小干扰RNA技术，我们证明了WRN敲低的细胞对烷基化剂甲磺酸甲酯过敏，这会造成DNA损伤，主要通过BER途径修复。此外，使用WRN敲除细胞的全细胞提取物进行修复试验表明，长贴片（LP） BER存在缺陷。这些发现表明，WRN在甲基化诱导的DNA损伤修复中起直接作用，并提示在LP BER过程中，WRN解旋酶和外切酶活性以及pol β都起作用。
Genome instability is a characteristic of cancer and aging, and is a hallmark of the premature aging disorder Werner syndrome (WS). Evidence suggests that the Werner syndrome protein (WRN) contributes to the maintenance of genome integrity through its involvement in DNA repair. In particular, biochemical evidence indicates a role for WRN in base excision repair (BER). We have previously reported that WRN helicase activity stimulates DNA polymerase beta (pol β) strand displacement synthesis in vitro. In this report we demonstrate that WRN exonuclease activity can act cooperatively with pol β, a polymerase lacking 3′–5′ proofreading activity. Furthermore, using small interference RNA technology, we demonstrate that WRN knockdown cells are hypersensitive to the alkylating agent methyl methanesulfonate, which creates DNA damage that is primarily repaired by the BER pathway. In addition, repair assays using whole cell extracts from WRN knockdown cells indicate a defect in long patch (LP) BER. These findings demonstrate that WRN plays a direct role in the repair of methylation-induced DNA damage, and suggest a role for both WRN helicase and exonuclease activities together with pol β during LP BER.