剪接因子SFRS5的泛素化和乙酰化修饰调控研究

项目名称： 剪接因子SFRS5的泛素化和乙酰化修饰调控研究

项目编号： No.31471326

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 郭兴

作者单位： 南京医科大学

项目金额： 80万元

中文摘要： 可变剪接是形成真核生物蛋白质多样性的重要原因，其异常与肿瘤形成、代谢紊乱、免疫疾病发生等密切相关，探讨可变剪接的调节机制具有重要的生物学意义。SFRS5作为一种重要的剪接调节因子，已知的调节机制集中于转录水平，而翻译后水平的调节机制知之甚少。我们前期发现，SFRS5可被泛素化和乙酰化修饰;乙酰化在K125位点竞争Smurf1介导的泛素化、抑制降解从而增强SFRS5的稳定性。在凋亡信号刺激下，其剪接底物CCAR1剪接体比例下降,诱发凋亡。本项目拟深入探讨乙酰化和泛素化修饰的具体机制和发生的生理条件;明确这两种修饰对于SFRS5剪接功能的影响;制备特异性的乙酰化抗体，利用裸鼠成瘤、临床样本筛查、敲除、敲入小鼠模型研究K125位点修饰与肿瘤及正常细胞代谢的关系;发掘鉴定新的剪接底物以全面揭示两种修饰对SFRS5剪接活性调控的普遍性。本项目对于理解剪接因子家族的翻译后修饰机制具有重要的启示作用。

中文关键词： 剪接因子；泛素化；乙酰化；细胞凋亡；肿瘤形成

英文摘要： Alternative splicing makes fundermental contributions to the plethora of eukaryotic proteomics. The abnormality of alternative splicing has been demonstrated to be tightly correlated with malignant tumor,metabolic disorders, autoimmune disseases and many other clinical syndromes. The pervasive study of the regulatory mechanisms of alternative study is a significant and cutting-edge direction. SFRS5 is a classical member of splicing regulators. The current knowledge of its regulation comes from the studies on its transcriptional level, however the post-translational regulation of SFRS5 remains largely unclear. We recently found that SFRS5 can be ubiquitinated and acetylated,and the potential ubiquitin ligase for SFRS5 is the HECT-type ubiquitin ligase Smurf1. Interestingly,the acetylation of SFRS5 on K125 site competes the SFRS5 ubiquitination by Smurf1 and then stabilizes SFRS5. Upon apoptosis inducer treatment, the activity of SFRS5 changed, which was reflected by the ratio of two isoforms of its splicing substrates, Cell Cycle and Apoptosis Regulator 1 (CCAR1). This resulted in apoptosis in various cell types. In this project, we plan to delineate the intricate mechanisms of the ubiquitination and acetylation as well as their physiological significance. Meanwhile we plan to study the outcomes on the splicing ablity and classical translation-promoting function of SFRS5. We will generate an acetylated SFRS5-specific antibody to detect the level of acetylated SFRS5 in tumor cells and evaluate the function of K125 modification in metabolism and tumorgenesis. Parallelly, we will use cell proliferation, apoptosis, migration, invasion assays and tumor formation assay in nude mice to investigate the functions of SFRS5 in tumor progression. Finally, we plan to use the biological tool ESE finder to discover the new substrate of SFRS5 which biological roles are pivotal and multiformed to better understand how these two modifications influence the basic splicing events of SFRS5. This project will make contribution to understand the post-translational regulation of splicing factors.

英文关键词： splicing factors;ubiquitination;acetylation;apoptosis;tumorigenesis