The mammalian small RNA machinery and its role in antiviral defenses

描述（由申请人提供）：了解病毒致病的分子基础是未来抗病毒疗法发展的基本要求。虽然我们对如何识别病毒和对抗病毒的各种方法了解很多，但仍有大量的细胞抗病毒免疫领域仍是未知的。本研究计划聚焦于其中一个领域。本研究提出的核心问题是小RNA或哺乳动物小RNA机制的组成部分是否有助于细胞对感染的反应。这个问题的重要性和通过实验解决这个问题的必要性可以通过广泛的初步数据来证明，这些数据表明，哺乳动物细胞中存在一种对抗病毒感染的新方法，但有待鉴定。为了了解哺乳动物小RNA通路与病毒感染反应之间的相互作用，我们发现了RNA诱导沉默复合物（RISC）抑制病毒复制的作用，分离了首个抑制RISC功能的哺乳动物病毒蛋白，并发现小RNA生物发生的关键角色Drosha在RNA病毒感染过程中主动易位到细胞质中。综上所述，我们相信这项研究为哺乳动物中未被发现的小rna介导的抗病毒反应提供了令人信服的证据。在这里，我们建议使用RISC病毒拮抗剂（称为VP55）来定义体内感染的小RNA反应，并表征Drosha如何参与这种抗病毒活性。本提案的总体目标是描述小RNA途径如何促进我们对病毒感染的反应。

DESCRIPTION (provided by applicant): Understanding the molecular basis for why viruses cause disease is an essential requirement for future development of antiviral therapeutics. While we know a great deal about how viruses are recognized and the various ways in which they are combated, there are still vast areas of cellular antiviral immunity that remain unknown. This research proposal focuses on one such area. The central question being addressed in this proposal is whether small RNAs, or components of the mammalian small RNA machinery, contribute to the cellular response to infection. The importance of this question and the need to address it experimentally can be justified through extensive preliminary data that suggest a novel means to combat virus infection is present in mammalian cells but awaits characterization. In an effort to understand the interplay between the small RNA pathway of mammals and the response to virus infection we have discovered the potency by which the RNA induced silencing complex (RISC) can inhibit virus replication, isolated the first mammalian virus protein which inhibits RISC function, and found that Drosha, a key player in small RNA biogenesis, actively translocates to the cytoplasm during RNA virus infection. Taken together, we believe this research provides compelling evidence for an unappreciated small RNA-mediated antiviral response in mammals. Here we propose to use the virus antagonist to RISC (called VP55) to define the small RNA response to infection in vivo as well as characterize how Drosha participates in this antiviral activity. The overall objective of this proposal is to delineate howthe small RNA pathway contributes to our response to virus infection.