利用拟南芥模式系统研究尿苷化参与miRNA稳定性调节的分子机制

项目名称： 利用拟南芥模式系统研究尿苷化参与miRNA稳定性调节的分子机制

项目编号： No.31471221

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 遗传学与生物信息学、细胞生物学

项目作者： 任国栋

作者单位： 复旦大学

项目金额： 86万元

中文摘要： miRNA是动植物生长发育的重要调控因子，其表达水平受到转录、加工和稳定性等多个层面的精细调控。过去十几年的探索使我们对miRNA的生物合成途径有了深入的了解，但是关于miRNA稳定性的研究才刚刚起步。申请人前期工作表明HESO1和URT1可以共同催化miRNA 3'末端尿苷化以促进miRNA降解，但是其作用机制尚不清楚。另外，参与miRNA截短和降解的酶也有待发现。本项目拟采用多种生物化学和分子生物学方法，进一步研究HESO1和URT1协同催化miRNA尿苷化的分子机理，尤其是在底物识别和酶促动力学上的异同；同时充分利用已有的遗传资源找寻参与miRNA截短和降解的酶基因以及探讨miRNA尿苷化和截短在miRNA稳定性调节中的关系，力图阐明两种不同修饰共存的生物学意义。本研究将拓展我们对小分子RNA稳定性调控的认识，同时为我们更好的利用小分子RNA实现细胞内基因表达精细调控奠定理论基础。

中文关键词： 模式植物；表观遗传学；基因沉默；微小RNA；尿苷化

英文摘要： miRNAs are key regulators of plant and animal development and their steady-state levels are fine controlled at both the transcriptional and posttranscriptional levels, including transcription, biogenesis and stability. Although the miRNA biogenesis pathway has been extensively investigated during the past decade, little is known about miRNA stability control. Our recent study showed that HESO1 and URT1 are terminal uridyl transferases that can uridylate unmethylated miRNAs to trigger their degradation. However, how uridylation triggers miRNA degradation is unclear. In addition, enzymes catalyzing miRNA truncation and degradation remain to be identified. In this proposal, we plan to employ various biochemical and molecular biological approaches to study how HESO1 and URT1 coordinate with each other in catalyzing miRNA uridylation and their roles in miRNA degradation. Moreover, taking the advantage of available rich genetic resource, this research also aims to identify novel enzymes that are responsible for miRNA truncation or degradation, which is critical for understanding the biological significance of the co-occurrence of uridylation and truncation, and their mechanistic roles in miRNA degradation. In conclusion, this research will expand our understanding on small RNA stability control and benefits our utilization of various small RNA based technology (e.g. artificial miRNA and RNAi) in fine-tuning of gene expression.

英文关键词： Model Plant;Epigenetics;Gene Silencing;microRNA;Uridylation