Biochemistry

Werner综合征(WS)是一种罕见的常染色体隐性遗传病，以过早衰老和遗传不稳定为特征，并与特殊的、罕见的癌症的高发病率有关。在WS，WRN中突变的基因属于RecQ解旋酶家族，编码3‘-gt；5’DNA解旋酶和3“-gt；5‘DNA外切酶活性。生化研究表明，解旋酶优先解开含有替代结构的DNA，外切核酸酶优先切除3’末端错配的核苷酸。WRN的克隆和纯化为我们提供了详细研究其生物化学的机会，并将这些发现与本项目中的其他项目结合起来，以了解野生型WS蛋白WRN如何抑制遗传不稳定和癌症。 为了深入了解WS蛋白在体内的功能，我们将1.鉴定和 鉴定与WRN在物理和功能上相互作用的蛋白质，以及2.建立体外模型系统以确定WRN参与交联修复。此外，我们还将 在普通人群中检测WRN单核苷酸多态性以了解功能效应， 并分析与WS，特别是肉瘤相关的癌症中的多态变异和WRN突变。 这些研究将为拟议的计划项目提供生化基础。

Werner syndrome (WS) is an uncommon autosomal recessive disease characterized by premature aging and genetic instability, and associated with a high incidence of specific, uncommon cancers. The gene mutated in WS, WRN, belongs to the family of RecQ helicases and encodes both 3' -> 5' DNA helicase and 3" -> 5' DNA exonuclease activities. Biochemical studies indicate that the helicase preferentially unwinds DNA harboring alternative structures and that the exonuclease preferentially excises mismatched nucleotides at the 3'-terminus. Cloning and purification of WRN affords us the opportunity to study its biochemistry in detail and use these findings in concert with other projects in this program to understand how the wild-type WS protein, WRN, suppresses genetic instability and cancer. In order to gain insights into the in vivo fianctions of the WS protein, we will 1. identify and characterize proteins that interact physically and functionally with WRN, and 2. establish model in vitro systems to determine the involvement of WRN in cross-link repair. In addition, we will examine WRN single nucleotide polymorphJsms in the general population for functional effects, and analyze polymorphic variants and WRN mutations in cancers associated with WS, in particular, sarcomas. These studies will provide the biochemical foundation for the proposed program project.