Functional interaction between the Werner syndrome protein and DNA polymerase δ
Functional interaction between the Werner syndrome protein and DNA polymerase δ
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DOI：
10.1073/pnas.97.9.4603
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发表时间：
2000-04-25
影响因子：
11.1
通讯作者：
Loeb, LA
中科院分区：
文献类型：
--
作者：
Kamath-Loeb, AS;Johansson, E;Loeb, LA
Werner综合征（WS）是一种遗传性疾病，其特征在于过早衰老、癌症发病率增加和基因组不稳定。WS基因编码1，432个氨基酸的多肽（WRN），其中心结构域与RecQ DNA解旋酶家族同源。纯化的WRN具有3 '->5'极性解旋DNA，并且还具有3 '->5'核酸外切酶活性。WRN相互作用蛋白的鉴定有助于阐明WRN的生理功能。我们在这里显示，WRN功能上与DNA聚合酶δ（pol δ）相互作用。一种DNA复制和DNA修复所需的真核聚合酶。WRN在不存在增殖细胞核抗原（PCNA）的情况下通过pol δ增加核苷酸掺入的速率，但不刺激真核DNA聚合酶α或pol δ或多种其它DNA聚合酶的活性。此外，我们发现与WRN的功能性相互作用是通过pol δ的第三亚基介导的：即，Pol 32 p，对应于最近鉴定的人pol δ的p66亚基。第三亚基的缺失消除了WRN的刺激，并且通过重建三亚基酶来恢复刺激。我们的研究结果表明，WRN可以促进聚合酶δ介导的DNA复制和/或DNA修复，并在WS细胞中的WRN-聚合酶δ相互作用的中断可能有助于以前观察到的S期缺陷和/或不寻常的敏感性，以有限数量的DNA损伤剂。
Werner Syndrome (WS) is an inherited disease characterized by premature onset of aging, increased cancer incidence, and genomic instability. The WS gene encodes a 1,432-amino acid polypeptide (WRN) with a central domain homologous to the RecQ family of DNA helicases. Purified WRN unwinds DNA with 3'-->5' polarity, and also possesses 3'-->5' exonuclease activity. Elucidation of the physiologic function(s) of WRN may be aided by the identification of WRN-interacting proteins. We show here that WRN functionally interacts with DNA polymerase delta (pol delta). a eukaryotic polymerase required for DNA replication and DNA repair. WRN increases the rate of nucleotide incorporation by pol delta in the absence of proliferating cell nuclear antigen (PCNA) but does not stimulate the activity of eukaryotic DNA polymerases alpha or epsilon, or a variety of other DNA polymerases. Moreover, we show that functional interaction with WRN is mediated through the third subunit of pol delta: i.e., Pol32p of Saccharomyces cerevisae, corresponding to the recently identified p66 subunit of human pol delta. Absence of the third subunit abrogates stimulation by WRN, and stimulation is restored by reconstituting the three-subunit enzyme. Our findings suggest that WRN may facilitate pol delta-mediated DNA replication and/or DNA repair and that disruption of WRN-pol delta interaction in WS cells may contribute to the previously observed S-phase defects and/or the unusual sensitivity to a limited number of DNA damaging agents.