EVOLUTION AND TAXONOMY OF RNA VIRUSES

蛋白质序列的详细计算机辅助比较分析 以及正链和双链RNA病毒的基因排列 被用来提出进化情景，并勾勒出一个新的， 这些病毒的系统发育分类学。更高级的RNA病毒类群 (目和纲)是基于系统发育树提出的 高度保守的蛋白质和基因组组织的比较。这个 两个正链RNA家族的异常基因组结构 病毒，即冠状病毒和星状病毒，被发现在 与各自的试验组合作。新月形体病毒 是一组具有异常大基因组的植物RNA病毒。确实是 表明除了复制基因的核心外， 正链RNA病毒组的数量，闭锁病毒具有 几个独特的基因。其中包括领袖木瓜酶样硫醇 最先由计算机分析预测的蛋白酶，随后 通过实验进行了演示。冠状冠状病毒的一个独特特征是 复制外壳蛋白基因，这也是最初 由计算机发现，然后在实验中发现。星际病毒是一个群体 动物病毒只与所谓的 类似于皮科纳的超群。星状病毒的一个独特特征，考虑到 相对较大的基因组大小(&gt；7kb)，是指基因的缺失 RNA解旋酶。尽管氨基酸有很大的不同 序列和基因组组织，包括冠状病毒和星状病毒 利用相同的、不同寻常的基因组表达机制，即 依赖RNA的RNA上游程序性核糖体框架移位 聚合酶基因。对这些病毒家族的研究具有重要的意义 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 虹膜病毒和痘病毒的研究是作为 与实验实验室合作。编码推定的基因 与细菌MUT蛋白相关的特定类型的GTP酶 在两组病毒中均可检测到锌指蛋白。一个人的基因 与DNA结合的HMG蛋白同源的蛋白质、DNA解旋酶和 DNA依赖的RNA聚合酶的最大亚基在 虹彩病毒。DNA解旋酶和DNA解旋酶的系统发育树分析 RNA聚合酶导致虹彩病毒和 痘病毒是独立于细胞基因进化的。

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.