The Role of HEN1 in MicroRNA Biogenesis in Arabidopsis

HEN1 在拟南芥 MicroRNA 生物发生中的作用

• 批准号: 0612958
• 负责人: Xuemei Chen
• 金额: $ 24.83万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-11-18 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0612958&HistoricalAwards=false
• 关键词: Role; HEN1; MicroRNA; Biogenesis; Arabidopsis

MicroRNAs (miRNAs), single-stranded RNAs of usually 21-25 nucleotides in length found in diverse eukaryotes, act as sequence-specific regulators of gene expression during normal growth and development. miRNAs are processed, by an RNAse III enzyme named Dicer, from longer transcripts that fold into stem-loop structures with the miRNAs being in the double-stranded regions. In addition to Dicer, two classes of proteins of unknown molecular functions, Argonaute and HEN1, have been implicated in miRNA biogenesis. The temporally or spatially restricted expression of many miRNAs suggests that miRNA biogenesis is tightly regulated during development. However, little is known about the pathway or the regulation of miRNA biogenesis. The goal of this research is to dissect the role of HEN1 in miRNA biogenesis using molecular genetic and biochemical approaches. In particular, this research will follow clues from previous observations, such as the accumulation of a potential miRNA precursor in a dicer mutant and the presence of heterogeneous miRNA species in the hen1-1 mutant to probe the potential roles of HEN1 in miRNA biogenesis, such as production, stabilization, or nuclear export of miRNA precursors or miRNAs. This investigation will shed light on the molecular function of HEN1, a pioneer protein with homologs from metazoans, in miRNA biogenesis and also provide insights into the poorly understood miRNA biogenesis process in plants, such as the steps involved to process the primary transcript to the mature miRNA and the subcellular locations of the processing steps.

MicroRNA（miRNA），通常在不同真核生物中发现的长度为21-25个核苷酸的单链RNA，在正常生长和发育过程中充当基因表达的序列特异性调节剂。 MiRNA是由称为DICER的RNase III酶从较长的转录物中处理的，该酶从较长的转录本中折叠成干循环结构，而miRNA位于双链区域。 除DICER外，未知分子功能的两类蛋白Argonaute和Hen1都与miRNA生物发生有关。 许多miRNA的时间或空间限制表达表明，在发育过程中，miRNA生物发生受到严格的调节。 但是，关于miRNA生物发生的途径或调节知之甚少。这项研究的目的是使用分子遗传和生化方法剖析HEN1在miRNA生物发生中的作用。 特别是，这项研究将遵循以前观察结果的线索，例如在培训剂突变体中的潜在miRNA前体的积累以及Hen1-1-1突变体中异质miRNA物种的存在，以探测HEN1在miRNA生物发生中的潜在作用，例如生产，稳定或miRNA前体或miRNA的核出口。这项研究将阐明HEN1的分子功能，Hen1是一种具有后生动物同源物的先锋蛋白，在miRNA生物发生中，还可以深入了解植物中的miRNA生物发生过程，例如，涉及的步骤，以将主要转录物处理到成熟的miRNA和处理步骤的下部位置。