MECHANISMS OF ACTION OF INTERFERON

干扰素的抗病毒和抗增殖作用一直是 与多种酶活性(2-5A合成酶、 核糖核酸内切酶、蛋白激酶)，当被激活时，抑制蛋白质 但这些酶的合成与抑制 RNA和DNA病毒的复制还没有被阐明。我们 在一种痘苗病毒感染的小鼠L细胞系统中发现 干扰素对体内病毒蛋白合成的抑制作用 与2-5A合成酶/核酸内切酶的激活和 病毒RNA的降解。相比之下，在许多老鼠和人类中 不同来源的细胞，痘苗病毒蛋白质合成不受 干扰素和一种新现象被发现，其中牛痘 产物可阻断2-5A合成酶和蛋白激酶活性。在这 方案，描述了以痘苗病毒为模型系统的实验 为了阐明：a)2-5A合成酶/核酸内切酶在体内的作用 干扰素介导的痘苗病毒蛋白抑制系统 合成；b)脱氧核糖核酸病毒，如牛痘病毒逃逸的机制 被干扰素系统阻断。为了确定该蛋白在体内的作用 2-5A合成酶/核酸内切酶对蛋白质合成的影响 病毒和细胞RNA的完整性程度与一组 翻译，如果某些RNA发生了特定的退化，并且如果这些 事件是病毒RNA在感染过程中形成的结果 感染。为了定义牛痘病毒如何逃脱由 干扰素介导的酶活性，我们将表征其性质和 具有干扰特性的痘苗产品的作用方式 细胞提取液和病毒粒子。为了进一步定义牛痘产品， 阻断干扰素的作用我们将检查病毒基因 通过DNA介导的基因转移进入细胞可以克服特定的 干扰素介导酶活性。通过检查这些细胞系统 其中细胞的干扰素反应可由牛痘病毒控制 基因(S)我们可以提供手段来定义负责的机制 抑制各种病毒的复制以及 干扰素的抗增殖作用。

The antiviral and antiproliferative actions of interferons have been correlated with a number of enzyme activities (2-5A synthetase, endoribonuclease, protein kinase), which, when activiated, inhibit protein synthesis but the relevance of these enzymes to the inhibition of replication of RNA and DNA-containing viruses has not been elucidated. We have found in a vaccinia virus infected mouse L cell system that the interferon-mediated inhibition of viral protein synthesis in vivo correlates with activation of the 2-5A synthetase/endonuclease and degradation of viral RNAs. In contrast, in a number of mouse and human cells of different origins, vaccinia protein synthesis is not inhibited by interferon and a novel phenomenon has been discovered where vaccinia products block the 2-5A synthetase and protein kinase activities. In this proposal, experiments are described using vaccinia virus as a model system to elucidate: a) the in vivo role of the 2-5A synthetase/endonuclease system in the interferon-mediated inhibition of vaccinia virus protein synthesis; b) the mechanism by which a DNA virus such as vaccinia escapes blockade by the interferon system. To determine the in vivo role of the 2-5A synthetase/endonuclease on protein synthesis we will establish to what extent the integrity of viral and cellular RNAs is related to a block of translation, if specific degradation of certain RNAs occurs and if these events are the result of the formation of viral RNA during the course of infection. To define how vaccinia virus escapes inhibition by the interferon-mediated enzyme activities, we will characterize the nature and mode of action of vaccinia products with interfering properties present in cell-extracts and virions. To further define the vaccinia products with blocking effects on interferon action we will examine whether viral genes introduced into cells by DNA-mediated gene transfer can overcome specific interferon-mediated enzyme activities. By examining these cell-systems where the interferon response of the cells may be controlled by vaccinia gene(s) we may provide the means to define the mechanisms responsible for inhibition of replication of various viruses as well as the antiproliferative actions of interferons.