CELLULAR SIGNALING BY DOUBLE STRANDED RNA

本研究将探讨双链RNA的细胞信号传导。双链RNA是基因转录、蛋白质合成和细胞生长的重要调节因子。dsRNA的多种细胞功能已在干扰素系统中被发现，其不同方面将在该计划的其他项目中进行研究。将使用缺陷细胞突变体分析dsRNA的转录信号传导。已经分离出一种这样的突变体，在拟议的研究过程中将产生更多的突变体。将检查突变细胞中可能参与dsRNA信号传导的候选蛋白质的缺陷。如果没有发现这样的缺陷，将用从野生型细胞制备的cDNA表达文库补充细胞，并克隆突变蛋白。在另外两个目标中，将研究在上一个资助期间克隆的两种dsRNA结合蛋白的细胞功能。PACT是一种与PKR相互作用并激活PKR的蛋白质，其激活过程的机制及其对转录信号、蛋白质合成和细胞生长调节的影响将被研究。P9O是另一种dsRNA结合蛋白，是一种核磷蛋白。它可能参与细胞周期调控和核RNA代谢将被调查。拟议的研究将提供有关dsRNA细胞功能的重要机制信息，dsRNA是病毒感染细胞中的主要调节因子。

Cellular signaling by double-stranded (ds) RNA will be investigated in this project. DsRNA is an important regulator of gene transcription, protein synthesis and cell growth. The multiple cellular functions of dsRNA have been discovered in the contexts of the interferon system, different aspects of which will be studied in the other projects of this program. Transcriptional signaling by dsRNA will be analyzed using defective cell mutants. One such mutant has been already isolated and more will be generated during the course of the proposed investigation. The mutant cells will be examined for defects in candidate proteins which might be involved in dsRNA signaling. If no such defect is found, the cells will be complemented with cDNA expression libraries made from wild-type cells and the mutated protein will be cloned. In two other aims, cellular functions of two dsRNA-binding proteins, which were cloned during the last funding period, will be investigated. One protein, PACT interacts with PKR and activates it. The mechanism of the activation process and its consequence on transcriptional signaling, protein synthesis and cell growth regulation will be studied. P9O, the other dsRNA-binding protein, is a nuclear phosphoprotein. Its possible involvement in cell cycle regulation and nuclear RNA metabolism will be investigated. The proposed studies will provide important mechanistic information about the cellular functions of dsRNA, a major regulator in virus-infected cells.