作为增加蛋白多样性的分子机理，RNA可变剪接对人类疾病有重要意义。我们发现可变剪接在细胞周期中被时序性调控，因而影响肿瘤生长。本研究根据我们前期工作基础 (Nat Stru Mol Biol 2012&2013;Nat Commu 2013；Cancer Cell 2014)，采用GFP报告基因系统并结合RNA-seq来研究在细胞周期中显著波动的剪接因子蛋白激酶CLK1。系统性鉴定CLK1所调控的剪接事件以及CLK1在细胞周期中对剪接因子的磷酸化,分析特定RNA剪接亚型对细胞周期的影响，并利用癌症基因图集来确定周期性可变剪接与肿瘤生长间的相关性。本课题的顺利实施将揭示细胞周期中RNA可变剪接的时序性调控机理及功能，并为癌症的发生机制研究提供新思路。

Alteration of alternative splicing (AS) plays important roles in human health and disease. We have previously discovered that AS of many genes shows periodic oscillations during cell cycle, providing a novel mechanism for temporal control of gene function in cell cycle. Here we propose to further investigate the regulation and function of these periodic AS events during cell cycle, and study how this temporal regulation of splicing can affect tumor cell proliferation. We will systematically identify and test the splicing regulatory cis-elements and trans-factors that control periodic splicing, and will mainly focus on an SR protein kinase, CLK1, which control a large number of AS events via phosphorylating this major class of splicing factors (i.e., SR proteins). During cell cycle, CLK1 level undergoes periodic oscillations through a negative feedback circuit, making it an ideal candidate as the master regulator of periodic AS. We will first determine how CLK1 control AS in a genomic scale, and further compare CLK1-regulated genes with genes containing periodic AS events. Mechanistically, we will measure the modification of various SR proteins by CLK1 during cell cycle. In addition, we will examine if certain periodic AS events are critical to cell cycle progression by over-expression or knock down specific splicing isoforms. Finally, we will use TCGA data to systematically study if the periodic or CLK1-regualted AS events are critical to tumor pathogenesis. We will examine potential association of these AS events with cancer progression, and will determine if these AS events can be used as novel prognostic markers. Collectively, these studies will reveal novel functions and regulatory mechanisms of periodic splicing during cell cycle, and will provide unconventional route for novel cancer therapy.