EVOLUTION AND TAXONOMY OF RNA VIRUSES

RNA 病毒的进化和分类

• 批准号: 3759311
• 负责人: E V KOONIN
• 金额: --
• 依托单位: NATIONAL LIBRARY OF MEDICINE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3759311
• 关键词: DNA binding protein; DNA directed RNA polymerase; Poxviridae; RNA virus; biochemical evolution; computer assisted sequence analysis; double stranded RNA; gene expression; genome; guanosinetriphosphatases; helicase; nonhistone nucleoprotein; nucleic acid sequence; protein sequence; virus classification; virus genetics; virus protein

Detailed computer-assisted comparative analysis of protein sequences and gene arrangement in positive-strand and double-stranded RNA viruses was used to propose evolutionary scenarios and to outline a new, phylogenetic taxonomy of these viruses. Higher taxa of RNA viruses (orders and classes) were proposed based on phylogenetic trees for highly conserved proteins and on comparison of genome organization. The unusual genome organization of two families of positive-strand RNA viruses, namely closteroviruses and astroviruses, was revealed in collaboration with the respective experimental groups. Closteroviruses are a group of plant RNA viruses with unusually large genomes. It was shown that in addition to the core of replicative genes typical of a number of groups of positive-strand RNA viruses, closteroviruses possess several unique genes. These include the leader papain-like thiol protease which was first predicted by computer analysis and subsequently demonstrated experimentally. A unique feature of closteroviruses is a duplication of the coat protein gene which also has been initially discovered by computer and then experimentally. Astroviruses are a group of animal viruses that are only distantly related to the so-called picorna-like supergroup. A unique feature of astroviruses, given the relatively large genome size (> 7 kilobases), is the absence of a gene for RNA helicase. In spite of the major differences in amino acid sequences and genome organization, both closteroviruses and astroviruses utilize the same, unusual mechanism of genome expression, namely programmed ribosomal frameshifting upstream of the RNA-dependent RNA polymerase gene. The study of these virus families has significantly broadened the scope of genome organizations and expression strategies known to exist in positive-strand RNA viruses. Analysis of several genes of iridoviruses and poxviruses was performed as part of the collaboration with experimental laboratories. Genes coding for putative GTPases related to the bacterial MutT proteins and for a specific type of Zn finger proteins were found in both virus groups. Genes for a protein homologous to DNA-binding HMG proteins, DNA helicase and the largest subunit of the DNA-dependent RNA polymerase were identified in iridoviruses. Analysis of the phylogenetic trees for DNA helicases and RNA polymerases has led to the conclusion that iridoviruses and poxviruses have evolved independently from cellular genes.

蛋白质序列的详细计算机辅助比较分析 正链和双链RNA病毒的基因排列 被用来提出进化的情景，并勾勒出一个新的， 这些病毒的系统发育分类。 RNA病毒的高级分类群 （目和类）提出了基于系统发育树， 高度保守的蛋白质和基因组结构的比较。 的 两个正链RNA家族的不寻常基因组结构 病毒，即线形病毒和星状病毒，被发现在 与各实验组合作。 线形病毒 是一组基因组异常庞大的植物RNA病毒。这是 除了典型的复制基因核心外， 许多组正链RNA病毒，线形病毒具有 几个独特的基因这些包括领导木瓜蛋白酶样硫醇 蛋白酶，首先通过计算机分析预测， 实验证明。 梭状病毒的一个独特特征是 复制的外壳蛋白基因，也已初步 由计算机发现，然后进行实验。星状病毒是一组 动物病毒与所谓的 Picorna类超群一个独特的特点，星状病毒，鉴于 相对较大的基因组大小（> 7个内切酶），是缺少一个基因 RNA解旋酶。尽管氨基酸有很大差异， 序列和基因组组织，包括线形病毒和星状病毒 利用相同的，不寻常的基因组表达机制，即 RNA依赖性RNA上游的程序性核糖体移码 聚合酶基因对这些病毒家族的研究 拓宽了基因组组织和表达策略的范围 已知存在于正链RNA病毒中。几个基因的分析 虹彩病毒和痘病毒的研究是 与实验室合作。 编码推定的 与细菌MutT蛋白相关的特定类型的GTP酶 在两组病毒中都发现了锌指蛋白。 的基因的 与DNA结合HMG蛋白同源的蛋白质，DNA解旋酶和 DNA依赖性RNA聚合酶的最大亚基被鉴定为 虹彩病毒DNA解旋酶系统发育树分析及 RNA聚合酶导致了虹彩病毒和 痘病毒独立于细胞基因进化。