Role of the RecQ4/RTS helicase in genome maintenance

描述(申请人提供)：Rothmund-Thomson综合征(RTS)是一种常染色体隐性遗传病，以生长缺陷、皮肤和骨骼异常为特征，并易患癌症。RECQ4基因是大肠杆菌RecQ基因的五个人类同源物之一，已在大多数RTS患者中发现突变。RecQ解旋酶被认为在调节同源重组和维持基因组完整性方面发挥作用。RecQ4蛋白已经在细菌中表达，纯化到接近均一的水平，并显示出具有单链DNA依赖的ATPase活性。该奖学金项目的目标将是在体外和体内对RecQ4蛋白进行表征，以确定其生化和遗传功能。具体地说，将研究RecQ4是否可以解开类似重组中间体的DNA底物，并确定RecQ4与人拓扑异构酶Illα的潜在相互作用。此外，还将采用遗传学方法来确定抑制RECQ4表达对细胞存活、细胞周期进展、DNA修复和人类细胞中同源重组的影响。

DESCRIPTION (provided by applicant): Rothmund-Thomson syndrome (RTS) is an autosomal recessive disorder characterized by growth deficiency, skin and skeletal abnormalities, and a predisposition to cancer. Mutations in the RECQ4 gene, one of five human homologs of the E. coli recQ gene, have been identified in the majority of RTS patients. RecQ helicases are thought to play roles in regulating homologous recombination and the maintenance of genomic integrity. The RecQ4 protein has been expressed in bacteria, purified to near homogeneity, and shown to possess ssDNA-dependent ATPase activity. The goal of this fellowship project will be to characterize the RecQ4 protein both in vitro and in vivo to determine its biochemical and genetic functions. Specifically, whether RecQ4 can unwind DNA substrates that resemble recombination intermediates will be investigated, and a potential interaction of RecQ4 with human topoisomerase Ill alpha will be ascertained. In addition, a genetic approach will be pursued to define the effect of inhibition of RECQ4 expression on cell survival, cell cycle progression, DNA repair, and homologous recombination in human cells.