精氨酸甲基转移酶AtPRMT5参与mRNA前体拼接的机理研究

蛋白质精氨酸甲基化由一类被称为蛋白精氨酸甲基转移酶(PRMT)的蛋白家族催化完成，参与调控细胞多种重要的生命过程。AtPRMT5是拟南芥中能够催化组蛋白和非组蛋白的对称性双甲基化的酶，参与调控植物生长发育的各个过程，包括叶片形态、生长速率、昼夜节律、对胁迫的响应、及通过下调开花抑制基因FLC的表达而促进开花等过程。进一步研究发现，AtPRMT5通过调控植物生命周期各个阶段中mRNA前体的正确加工，从而保证了植物正常的生长发育过程。但对其调控的分子机制知之甚少。本项目将围绕高等植物中蛋白质精氨酸甲基转移酶AtPRMT5的作用机制这一关键的科学问题，综合采用遗传学、生物化学、分子生物学、转录组学和生物信息学等多学科研究手段，解析AtPRMT5参与mRNA前体拼接的分子机制，分析造成atprmt5突变体生长发育异常表型的可能原因，以期阐明蛋白质精氨酸甲基化修饰参与植物生长发育过程的分子调控机制。

Protein arginine methylation, catalyzed by the Protein Arginine Methyltransferases (PRMTs), is involved in multiple key biological processes. In the model plant Arabidopsis, we reported that AtPRMT5 can symmetrically methylate histones and nonhistone proteins, and regulate the plant developmental processes, including leaf morphology, growth rate, circadian clock, response to stresses, and FLC-dependent flowering time control. Further study showed that the involvement of AtPRMT5 in plant developmental processes is the integrative effects attributed to the accurate splicing of diverse genes that are not restricted to any single target. However, the precise mechanism remains to be elusive. In this project, we will mainly focus on the functional analysis of AtPRMT5 in pre-mRNA splicing. By using genetics, biochemistry, molecular, transcriptome, and bioinformatics, we will dissect the molecular mechanism of AtPRMT5 in pre-mRNA splicing, analyze the possible reasons for the developmental defects of atprmt5 mutants, and finally elucidate the regulatory mechanism of arginine methylation in plant development.