mRNA核输出通路的异常会引起一系列相关疾病的发生，包括癌症。由于mRNA核输出通路的多样性和新药研发的局限性，使这些疾病得不到针对性治疗，因此，深入研究mRNA核输出通路的分子机制具有重要意义。本研究拟应用Knockdown技术制备SUN1缺失的HeLa细胞，利用RNAseq和生物信息学的方法分析胞质差异mRNA的类型及特征。通过生物化学和细胞生物学的手段检测SUN1是否可以被aPKC所磷酸化及其磷酸化的关键位点，这些位点的突变体与NXF1和Nup153的结合能力是否发生改变以及突变体对mRNA核输出的影响。借助CRISPR-Cas9基因编辑技术制备SUN1缺失或突变的斑马鱼突变体，分析突变体的遗传、生化和细胞学表型。结合细胞水平的研究，深入探索SUN1作用于mRNA核输出的分子机制。该研究一方面充实了mRNA核输出通路的基础理论；另一方面为相关疾病的药物筛选和临床精准治疗提供了新思路。

Abnormalities in the nuclear mRNA export pathway can cause a series of human diseases, including cancer. Due to the diversity of nuclear mRNA export pathway and the limited drug development, various diseases associated with the malfunction of nuclear mRNA export pathway cannot be treated accurately. It is very important to understand the molecular mechanism of nuclear mRNA export pathway in order to treat these diseases effectively. In this proposed study, the knockdown technique will be used to create HeLa cells deficient in SUN1, an inner nuclear envelope protein. The RNAseq and bioinformatic methods will be used to analyze and characterise any changes in cytoplasmic mRNAs. The phosphorylation status of SUN1 will be analyzed with biochemical and cell biological methods to determine whether SUN1 can be phosphorylated by aPKC, the crucial amino acids for phosphorylation if any, the effect on the interaction of SUN1 with NXF1 (nuclear export factor 1) and Nup153 (nucleoporin 153), and on nuclear mRNA export. In addition, CRISPR-Cas9 DNA editing tool will be employed to generate mutants of SUN1 in zebrafish. The SUN1 mutant zebrafish will be then extensively analyzed for the genetic, biochemical and cellular characteristics. Taking together, the results to be obtained by the completion of this proposal will provide: 1) a better understanding for the molecular mechanism of SUN1 function in mRNA export pathway; 2）the new insight for drug screening and clinical precision treatment of related diseases.