Cell Function

该项目的长期目标是提供Werner综合征蛋白（WRN，也称为RECQ 3或RECQL 2）在人体细胞中的体内功能的详细分子描述。具体目标侧重于回答三个问题： 1.确定WRN在人体细胞中的功能途径; 2.在人体细胞中鉴定WRN功能的体内底物;和 3.确定缺乏WRN功能的细胞中DNA损伤反应途径的激活和反应性。 本工作将验证四个假设：1）WRN在体细胞中的作用是解决异常的DNA结构或促进DNA损伤的修复，这些DNA损伤可以阻止、停止或破坏S期的DNA复制; 2）WRN可能在停止或退化的复制叉的修复中发挥直接作用; 3）这些解决/修复功能依赖于WRN蛋白的催化活性;和4）DNA损伤反应途径在缺乏WRN的人体细胞中被组成性激活，导致细胞周期进程、活力和基因组稳定性的降低。WRN蛋白在核酸代谢中的生理作用的鉴定将提供WRN如何确保基因组稳定性的详细理解，以及确定WRN功能丧失如何促进遗传不稳定性、诱变和细胞生长缺陷的模型，这些是Werner综合征发病机制的核心。

The long term goal of this project is to provide a detailed molecular description of in vivo functions of the Werner syndrome protein (WRN, also known as RECQ3 or RECQL2) in human somatic cells. Specific Aims focus on answering three questions: 1. defining the WRN functional pathway in human somatic cells; 2. identifying in vivo substrates for WRN function in human somatic cells; and 3. determining DNA damage response pathway activation and responsiveness in cells lacking WRN function. This work will test four hypotheses: 1) that WRN acts in somatic cells to resolve aberrant DNA structures or promote the repair of DNA damage that can block, stall or disrupt DNA replication during S-phase; 2) that WRN may play a direct role in the repair of stalled or regressed replication forks; 3) that these resolution/repair functions depend on both catalytic activities of the WRN protein; and 4) that DNA damage response pathways are constitutively activated in human somatic cells that lack WRN, leading to decrements in cell cycle progression, viability and genomic stability. The identification of physiologic roles for the WRN protein in nucleic acid metabolism will provide a detailed understanding of how WRN acts to insure genomic stability, and a model to determine how loss of WRN function promotes the genetic instability, mutagenesis and cellular growth deficits that are central to Werner syndrome pathogenesis.