前体mRNA的选择性剪切决定了生物体的基因表达和蛋白的多样性，mRNA剪切调控紊乱已被证明与多种癌症发病相关。前体mRNA内含子3'剪切位点识别是非常关键的一步，并有多种剪切因子参与。在早期剪切体中，SF1与U2AF共同定义3'剪切位点。SF1识别前体mRNA分支点序列，同时SF1 N端区域与U2AF65相互作用。SF1的磷酸化被认为是前体mRNA剪切中重要的调控手段之一。本项目将利用生化方法实现对SF1体外特异性磷酸化，结合质谱、核磁共振以及X-ray 晶体衍射技术对磷酸化SF1蛋白以及相关复合物大分子进行结构变化和动力学研究。本项目将揭示SF1磷酸化在mRNA剪切调控的分子机理，理解SF1磷酸化在生物体中的功能，从而解释因mRNA剪切调控紊乱导致人类多种癌症的发病机制。

Pre-mRNA alternative splicing is essential for gene expression and protein diversity. A malfunction in regulation of pre-mRNA splicing has been linked to tumourigenesis. Recognition of 3' splice site, which involves several splicing factors, has been proved a key step in pre-mRNA splicing. In complex E, SF1 and U2AF cooperatively define 3' splice site. SF1 recognizes pre-mRNA at branch-point sequence and its N-terminal domain interacts with U2AF65. It has been proposed that SF1 phosphorylation provides a crucial way for regulation of pre-mRNA splicing. In this project, we will perform in vitro specific phosphorylation of SF1 using biochemical methods. Combined MS, NMR and X-ray crystallography techniques, we will determine 3D structure of phosphorylated SF1 and the related complexes.The dynamics will be investigated as well. Our studies will provide first structural insight for the molecular mechanisms of pre-mRNA splicing regulation by SF1 phosphorylation. We will reveal the impact of SF1 phosphorylation in gene expression. This project will contribute significantly to understanding the pathogenesis of cancers linked to malfunction of pre-mRNA splicing regulation.