Role of Methylation in MicroRNA Metabolism in Arabidopsis

MicroRNAs(MiRNAs)和siRNAs(SiRNAs)构成了两类主要的小调控RNA，它们在植物、真菌和动物的发育、代谢和基因组组织中发挥着至关重要的作用。在之前NSF资助的一个项目中，Pi的团队在植物miRNA生物发生中发现了3‘末端核苷酸2’OH甲基化的新步骤。2‘-O-甲基保护miRNAs的尿苷化活性和核酸外切酶活性。在这个项目中，Pi和co-Pi的小组将使用生化方法来探索甲基化和尿酸化的功能，并使用遗传学方法来识别编码尿苷酸酶和/或核酸外切酶的基因。小RNA对生物体的发育和生理有着深远的影响。了解小RNA是如何产生、修饰和降解的，为探索涉及小RNA调控的各种生物过程提供了智力基础。虽然小RNA是如何从它们的前体被加工出来的是众所周知的，但关于它们是如何被修饰或降解的却知之甚少。通过揭示小RNA修饰和降解的机制，这项研究将对小RNA领域产生深远的影响，最终将有助于加深对小RNA生物学的理解，并有助于开发基于小RNA的技术来改进农业。该项目还将为一些本科生提供研究机会，包括来自代表性不足的少数族裔的学生。

MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) constitute two major classes of small regulatory RNAs that play crucial roles in development, metabolism, and genome organization in plants, fungi and animals. In a previous NSF funded project, the PI's group uncovered a new step in plant miRNA biogenesis methylation of the 2' OH of the 3' terminal nucleotides. The 2'-O-methyl group protects miRNAs from a uridylation activity and an exonuclease activity. In this project, the PI's and co-PI's groups will employ biochemical approaches to probe the functions of methylation and uridylation and to use genetic approaches to identify the genes encoding the uridylation enzyme and/or the exonuclease.Small RNAs have a profound impact on an organism's development and physiology. Understanding how small RNAs are generated, modified and degraded provides the intellectual foundation to probe various biological processes involving small RNA regulation. Although how small RNAs are processed from their precursors is well understood, little is known about how they are modified or degraded. By uncovering mechanisms in small RNA modification and degradation, this research will have profound impacts on the small RNA field and will ultimately contribute to a deeper understanding of small RNA biology and to the development of small RNA-based technologies to improve agriculture. The project will also provide research opportunities for a number of undergraduate students, including ones from underrepresented minorities.