The Role of Pre-miRNA Loop in Target Regulation by microRNA Genes

Pre-miRNA 环在 microRNA 基因靶标调控中的作用

• 批准号: 8777620
• 负责人: CHANG-ZHENG CHEN
• 金额: $ 66.74万
• 依托单位: ACHELOIS PHARMACEUTICALS, INC.
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8777620
• 关键词: Role; Pre; miRNA; Loop; Target

ABSTRACT MicroRNA (miRNA) genes encode an abundant class of ~22-nucleotide small RNAs that are thought to control gene expression at the post-transcriptional levels. Although the importance of miRNA-mediated gene regulation is now evident, as miRNA genes were shown to play diverse functional roles in animals, their mechanisms of action remain elusive. We have recently found that miRNA genes encoding identical mature miRNAs could have distinct biological activities that are determined by their cognate pre-miRNA loops, revealing unexpected regulatory complexity encoded in the pre-miRNA loops. These findings prompted us to reexamine some of the fundamental assumptions in the miRNA field. It was noted in the original discovery of the C. elegans lin-4 gene that mutations and deletions in lin-4 genes invariably affect including the primary (pri), precursor (pre), and mature miRNA species, which all contain sequences complementary to cognate target genes. Thus, phenotypes observed for loss of miRNA genes in worms and mice cannot be attributed to mature miRNA specie alone. Together, the limitations of current assumption and our surprising discovery of pre-miRNA loop function suggest that pri- and pre-miRNA species may play direct roles in target gene regulation. Here we propose to examine the mechanisms by which pre-miRNA loops control activity of miRNA genes using biochemical and genetic approaches. We will further dissect the structure and sequence elements beyond mature miRNA regions that are important for the activity of miRNA genes (aim 1), identify the protein and RNA components that contribute to the pre-miRNA loop functions (aim 2), and delineate the roles of premiRNA loop nucleotides in target gene recognition (aim 3). The proposed study will shed fundamental insights into gene regulation by miRNA genes and yield novel principles for target gene prediction and for designing more efficient gene silencing molecules targeting messenger RNAs and miRNA genes.

抽象的 microRNA（miRNA）基因编码一类〜22-核苷酸小RNA，被认为可以控制 转录后水平的基因表达。虽然miRNA介导的基因的重要性 现在的调节是显而易见的，因为miRNA基因被证明在动物中起多种功能作用， 行动机制仍然难以捉摸。我们最近发现编码相同成熟的miRNA基因 miRNA可能具有不同的生物学活性，这些生物活性由它们的同源前miRNA循环决定， 揭示了MIRNA环中编码的意外调节复杂性。这些发现促使我们 重新审查mirna领域中的一些基本假设。在原始发现中指出 LIN-4基因突变和缺失的LIN-4 C. e秀隐杆基因总是影响包括主要的 （PRI），前体（PRE）和成熟的miRNA物种，它们都包含互补的序列 靶基因。因此，观察到蠕虫中miRNA基因丧失的表型不能归因于 单独成熟的mirna。一起，当前假设的局限性以及我们对 MIRNA循环函数表明，PRI-MIRNA物种可能在靶基因中发挥直接作用 规定。在这里，我们建议检查miRNA的前MIRNA循环活性的机制 使用生化和遗传方法的基因。我们将进一步剖析结构和序列元素 除了成熟的miRNA区域，对miRNA基因的活性很重要（AIM 1），鉴定蛋白质 以及有助于前MIRNA循环函数（AIM 2）的RNA成分，并描述PremiRNA的作用 靶基因识别中的环核苷酸（AIM 3）。拟议的研究将提供基本的见解 通过miRNA基因调节基因，并产生目标基因预测的新原理和设计 靶向信使RNA和miRNA基因的更有效的基因沉默分子。