The functional role of DRH-1 in RNAi directed viral immunity

DRH-1 在 RNAi 定向病毒免疫中的功能作用

• 批准号: 8242983
• 负责人: Rui Lu
• 金额: $ 7.4万
• 依托单位: LOUISIANA STATE UNIV A&M COL BATON ROUGE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8242983
• 关键词: Antiviral Agents; Biogenesis; Biological Models; Biological Process; Biomedical Research; Boxing; Caenorhabditis elegans; Cleaved cell; Double-Stranded RNA; Enzymes; Gene Silencing; Genetic; Genetic Models; Goals; Homologous Gene; Housing; Human; Immunity; Insecta; Interferons; Invaded; Invertebrates; Lead; Light; Mammals; Mediating; Natural Immunity; Nematoda; Play; Process; Proteins; RNA Helicase; RNA I; RNA Interference; RNA-Induced Silencing Complex; Replicon; Research; Ribonuclease III; Role; Signal Pathway; Small Interfering RNA; Testing; Transcript; Transgenes; Viral; Virus; analog; cellular targeting; mutant; novel; plant fungi; sensor; success; viral RNA; viral detection

DESCRIPTION (provided by applicant): RNA interference (RNAi), or RNA silencing, is a novel antiviral mechanism conserved in fungi, plants and invertebrates. RNAi directed viral immunity (RDVI) is a stepwise process that begins with the processing of viral replication intermediates (in the form of double stranded RNA (dsRNA)), into small interfering RNA (siRNA) duplexes by RNase III enzymes. These virus-derived siRNAs (viRNAs) will then be incorporated into an RNA induced silencing complex (RISC) and serve as sequence guide for target viral RNA selection. Within the RISC, an Argonaut (AGO) protein cleaves the viral RNAs selected by viRNAs. Increasing evidence suggests that putative RNA helicases also play important roles in RDVI across kingdoms. However, how these RNA helicases contribute to RDVI remains largely unclear. DRH-1 is a putative RNA helicase conserved in both the Caenorhabditis elegans (C .elegans) nematode and mammals. Previously, our studies have demonstrated that DRH-1 is required for RDVI but becomes dispensable when RNAi is triggered to target cellular transcripts. Because DRH-1 is known to function downstream of siRNA biogenesis, this finding suggests that DRH-1 discriminates invading viral RNAs from cellular transcripts in mediating RNA silencing if we can provide further evidence that siRNAs in cellular gene silencing can mediate efficient virus silencing in the presence of DRH-1. Interestingly, DRH-1 is not conserved in fungi, plants or insects but shares significant sequence identity with RIG-I, a mammalian cytosolic virus sensor. RIG-I discriminates invading viral RNAs from cellular transcripts thereby to induce interferon mediated antiviral innate immunity upon virus detection, our studies thus support a hypothesis that DRH-1 is a RIG-I function analog that discriminates between invading viral RNAs and cellular transcripts thereby to selectively mediate virus silencing irrespective of the origin of silencing siRNAs. To test this hypothesis here we propose to: (1) determine if DRH-1 discriminates replicating viruses from cellular transcripts in mediating RNA silencing regardless of the origin of silencing siRNAs (Specific Aim 1, Research Strategy section, page 4); (2) determine if DRH-1 discriminates between replicating and non-replicating viruses in mediating RNA silencing (Specific Aim 2, Research Strategy section, page 6). The proposed studies are expected to not only help define a functional role for DRH-1 in worm RDVI but also establish C. elegans as a genetic model for mechanistic studies of virus sensing by RIG-I like RNA helicases. Novel findings from the proposed studies may also shed light on some nematode-specific features of RDVI since DRH-1 is not conserved in fungi, plants or insects. PUBLIC HEALTH RELEVANCE: In mammals, including humans, an RNA helicase, termed RIG-I, functions as a virus sensor in antiviral innate immunity. Here we propose to delineate a functional role for DRH-1, a RIG-I homologue found in Caenorhabditis elegans (C. elegans). Because C. elegans represents one of the best genetic models for modern biomedical research the proposed studies have the potential to establish C. elegans as a genetic model for mechanistic study of virus sensing by RIG-I.

描述（由申请人提供）：RNA干扰（RNAI）或RNA沉默，是一种在真菌，植物和无脊椎动物中保守的新型抗病毒机制。 RNAi定向病毒免疫（RDVI）是一个逐步过程，始于病毒复制中间体的处理（以双链RNA（DSRNA）的形式）进入小型干扰RNA（siRNA）双链体，由RNase III酶进行。然后，这些病毒衍生的siRNA（VIRNA）将被掺入RNA诱导的沉默复合物（RISC）中，并用作靶向病毒RNA选择的序列指南。在RISC中，Argonaut（AGO）蛋白质裂解了Virnas选择的病毒RNA。越来越多的证据表明，假定的RNA解旋酶在整个王国的RDVI中也起着重要作用。但是，这些RNA解旋酶如何促进RDVI仍然在很大程度上不清楚。 DRH-1是秀丽隐杆线虫（c .Elegans）线虫和哺乳动物中保守的假定RNA解旋酶。以前，我们的研究表明，RDVI需要DRH-1，但是当RNAi被触发到靶细胞转录本时，可以使其具有分配。由于已知DRH-1在siRNA生物发生的下游起作用，因此这一发现表明DRH-1在介导RNA沉默的细胞转录物中区分入侵病毒RNA，如果我们可以提供进一步的证据表明细胞基因沉默中的siRNA可以在存在DRH-1的情况下介导有效的病毒silencing。有趣的是，DRH-1在真菌，植物或昆虫中并不保守，而是与哺乳动物胞质病毒传感器Rig-I具有重要的序列身份。 RIG-I discriminates invading viral RNAs from cellular transcripts thereby to induce interferon mediated antiviral innate immunity upon virus detection, our studies thus support a hypothesis that DRH-1 is a RIG-I function analog that discriminates between invading viral RNAs and cellular transcripts thereby to selectively mediate virus silencing irrespective of the origin of silencing siRNAs.为了在这里检验这一假设，我们建议：（1）确定DRH-1是否在介导RNA沉默中的细胞转录物中复制病毒是否不论沉默siRNAS的起源如何（特定目标1，研究策略部分，第4页）； （2）确定DRH-1在介导RNA沉默中是否区分复制和非复制病毒（特定目标2，研究策略部分，第6页）。拟议的研究不仅有助于在蠕虫RDVI中定义DRH-1的功能作用，而且还建立了秀丽隐杆线虫作为一种遗传模型，用于通过RIG-I（如RNA Helicases）对病毒感测的机理研究。拟议研究中的新发现也可能阐明RDVI的某些线虫特异性特征，因为DRH-1在真菌，植物或昆虫中没有保守。 公共卫生相关性：在哺乳动物中，包括人类，一种称为RIG-I的RNA解旋酶，是抗病毒药性先天免疫中的病毒传感器。在这里，我们建议描述DRH-1的功能作用，DRH-1是秀丽隐杆线虫（秀丽隐杆线虫）中发现的RIG-I同源物。由于秀丽隐杆线虫代表了现代生物医学研究的最佳遗传模型之一，因此拟议的研究有可能建立秀丽隐杆线虫作为RIG-I对病毒传感的机械研究的遗传模型。