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开发抗病毒治疗的基本要求。虽然我们知道很多关于病毒是如何识别的，以及它们被对抗的各种方式，但仍然有大量的细胞抗病毒免疫领域仍然未知。本研究计划的重点就是这样一个领域。在这个提议中要解决的中心问题是小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需要解决它的实验可以证明通过广泛的初步数据，表明一种新的手段来对抗病毒感染是存在于哺乳动物细胞，但等待表征。为了了解哺乳动物的小RNA途径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）抑制病毒复制的效力，分离了第一个抑制RISC功能的哺乳动物病毒蛋白，并发现Drosha，小RNA生物合成的关键参与者，在RNA病毒感染期间主动易位到细胞质中。总之，我们相信这项研究为哺乳动物中未被重视的小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的病毒拮抗剂（称为VP55）来定义体内感染的小RNA反应，以及表征Drosha如何参与这种抗病毒活性。这个建议的总体目标是描述小RNA通路如何有助于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.