去泛素化酶USP19参与DNA损伤修复及有丝分裂调控的分子机制研究

细胞周期调控异常与肿瘤发生密切相关，染色体不稳定性是肿瘤细胞的重要特征，与M期染色体错误分离及DNA损伤修复调控异常密切相关。然而目前，在肿瘤发生过程中导致染色体不稳定性的具体调控机制并不十分清楚。本课题组前期通过系列工作发现了DNA损伤周期检查点和有丝分裂调控的关键机制(2011 Nature cell biology； 2013 PNAS). 近年来课题组建立了基于有丝分裂的siRNA筛选平台，利用该平台，我们进发现特异调控染色体分离的新功能蛋白质USP19。敲低USP19导致M期染色体错误分离， 且USP19参与DNA损伤修复。本项目在此重要线索基础上，通过免疫亲和纯化及质谱鉴定在M期和DNA损伤修复过程中与USP19动态结合的蛋白，以期阐明其调控染色体不稳定性的分子机制；利用USP19敲除小鼠和肿瘤临床样品，从动物及临床水平全面阐述USP19对肿瘤发生发展的影响。

Cell cycle deregulation is closely related to tumorigenesis, and chromosomal instability is a common feature of most human cancer which is associated with both uncontrolled whole chromosome mis-segregation in mitosis and DNA damage repair. However, the mechanisms underlying chromosomal instability in cancer remain unclear whose regulation mechanism has been a new frontier in life science, recently. In previous study, we found new mechanism regulating the DNA damage checkpoint activation and mitosis progression (Nature Cell Biology, 2011 and PNAS, 2013). Here, using siRNA high-throughput screening platform in live cell, we found that knockdown deubiquitinases USP19 (ubiquitin specific peptidase 19) caused increased proportion of chromosome mis-segregation. Also, USP19 is required for normal DNA repair. Based on these findings, we next plan to further explore the molecular mechanism of USP19 in maintaining chromosome stability and suppressing tumorigenesis. Our main strategy is to identify dynamic binding protein with USP19 by immunoaffinity purification assay and mass spectrometry and reveal the substrcats regulated by USP19 through ubiquitin modification. In addition, we will identify the detailed mechanism of USP19 in regulation chromosome instability and tumorigenesis by using mouse model and human clinical tumor samples.Through all the above efforts, we might find a new regulation mechanism of tumorigenesis and provide a fundamental basis for the development of anti-cancer drugs.