CARDIOVIRAL PROTEASES AND COMPARATIVE GENOME STRUCTURE

小核糖核酸病毒引起的疾病的医学和农业重要性 长期以来一直针对这些药物进行深入的实验室研究。的 家族包括多种病原体，例如 小儿麻痹症、犀牛、口蹄疫、甲型肝炎、科萨基和 鼠心病毒（除其他外）。RNA基因组的小尺寸 （约8，000个碱基）和等离子体相对简单的性质， 衣壳外壳允许基因组的容易操作， cDNA拷贝，并确定几种病毒粒子结构，以原子 分辨率这些强大的工具无法抵挡， 许多关于特定感染如何或为什么 确实在其自然界中引起一种特定的疾病过程， 主持人这些过程的核心是对所有 病毒生命周期的各个方面，特别是那些在病毒传播过程中发生的方面。 感染细胞这些研究不仅揭示了（可利用的） 特别是病毒表型的个体性，但也作为 对基本生物现象内部运作的批判性探索 其通过感染的破坏可以介导 疾病 该计划的重点是小鼠心脏病毒，脑心肌炎 病毒（EMCV）和孟戈病毒。心脏病毒RNA的特殊倾向 促进在无细胞提取物中的有效翻译，是 这些基因组，并使这些分离物非常有用 皮科病毒生命的分子解剖实验对象 周期本次调查的目标是探索和定义 心脏病毒属与其他成员的关系 piconavirus家族，并利用心脏病毒的独特功能 来研究关于微RNA病毒的基本分子问题 翻译、蛋白水解加工和形态发生。具体目标 （1）定义所需的序列和结构上下文， 新的NPGP“自杀”裂解，负责主要的 心脏病毒多聚蛋白的蛋白水解加工;（2）评估 引入病毒3C的工程突变的体内效应 蛋白酶、其加工位点或其他相关基因组位置，以及 将这些结果与特定阶段或缺陷相关联， （3）探讨不同的序列和结构 心脏病毒RNA的5'非编码区内的元件，并评估 他们在独立于上限的翻译启动和 在自然感染期间病毒诱导的宿主蛋白质关闭;以及（4） 通过计算机比较和对比所有可用的piconavirus序列数据 分析，特别强调对经修订的 科的分类学排序。创新的计算机生成图形 病毒体衣壳表面的内部和外部的展示也将被 先进的，详细的分子表面图和地形特征 比较。

The medical and agricultural importance of picornavirus-caused disease has long targeted these agents for intensive laboratory study. The family encompasses a diverse variety of pathogenic agents, such as polio, rhino, foot-and mouth-disease, hepatitis A, coxsackie, and the murine cadioviruses (among others). The small size of the RNA genome (about 8,000 bases) and the relatively simple nature of the icosametric capsid shell have allowed facile manipulation of genomes as infectious CDNA copies, and determination of several virion structures to atomic resolution. These powerful tools not withstanding, there still remain many unresolved questions about how or why a specific infection does indeed bring about a particular course of disease within its natural host. Central to these processes is the molecular examination of all facets of a virus life cycle, especially those ensuing within the infected cell. Such studies not only bring to light the (exploitable) individualities of particular viral phenotypes, but also serve as critical probes to the inner workings of elementary biological phenomena whose disruption through infection can mediate the expression of disease. This program focuses on the murine cardioviruses, encephalomyocarditis virus (EMCV) and Mengovirus. The special propensity of cardioviral RNAs facilitate efficient translation in cell-free extracts, is a hallmark of these genomes, and makes these isolates exceptionally useful experimental subjects for molecular dissection of the pico mavirus life cycle. The goals of this investigation are to explore and define the relationship of the cardiovirus genus to other members of the piconavirus family, and to exploit the unique features of cardioviruses to examine fundamental molecular questions about piconaviral translation, proteolytic processing and morphogenesis. The specific aims are: (1) To define the sequence and structural contexts required for the novel NPGP "suicide" cleavage that is responsible for primary proteolytic processing of cardioviral polyprotein; (2) To evaluate the in vivo effects of engineered mutations introduced into the viral 3C protease, its processing sites, or other relevant genomic locations, and to correlate these results with specific phases or defects in the cardioviral life cycle; (3) To probe distinctive sequence and structural elements within the 5' noncoding region of cardioviral RNAs, and assess their responsibilities in cap-independent translation initiation and in viral-induced host protein shut-off during natural infection; and (4) To compare and contrast all available piconavirus sequence data by computer analysis, with special emphasis of correlative support for a revised taxonomic ordering of the family. Innovative, computer-generated graphic displays of internal and external virion capsid surfaces will also be advanced, for detailed molecular surface maps and topographical feature comparisons.