GENOME ORGANIZATION AND EVOLUTION OF RNA VIRUSES

详细的计算机辅助蛋白质序列比较分析& 正链、负链和双链基因排列 进行RNA病毒以预测基因产物的功能， to derive推导principles原则of genome基因组organization组织，and to propose建议evolutionary进化 场景RNA病毒的基因组很小，但基因组序列完整 这些病毒的大多数已知组的代表是 目前可用的，允许大规模的比较和演变 问题研究正链RNA病毒具有有限数量的保守的 主要参与基因组复制和表达的蛋白质。 两种类型的推定甲基转移酶结构域，其中之一是保守的 在类α超群病毒中，另一种在黄病毒中， 已经被确认。戊型肝炎病毒多聚蛋白的结构域组织 研究表明，这种病毒与 风疹病毒和甜菜坏死黄脉病毒，属植物糠病毒。 这些病毒的进化似乎涉及几个基因组 重排事件。推测的木瓜蛋白酶样蛋白酶结构域是 在这些病毒的多聚蛋白中鉴定。分析 甜菜黄化梭状病毒基因组具有独特的基因结构， 其基因编码与两种蛋白质相关的蛋白质， 不同的正链RNA病毒群，以及细胞热休克 proteins.结果表明，该病毒的外壳蛋白基因是 复制的这是第一个外壳蛋白基因复制的例子， 具有细长颗粒的病毒。进化的一般概念 正链RNA病毒的基础上的相互作用， 基因阵列和基因模块改组正在开发中。工作 病毒基因组组织和衍生信息汇总 正在进行中。序列比较 由双链RNA编码的蛋白质显示出非常有限的保守性。 不同群体之间唯一保守的序列是一个结构域， 依赖RNA的RNA聚合酶。这个序列与 正链RNA病毒的聚合酶。系统发育分析 表明双链RNA病毒可能不是单系的， 组不同的双链RNA病毒群可能已经进化 来自不同的正链RNA病毒。 该项目的意义在于比较的独特机会 大量完整基因组的组织， 彼此之间的相似程度，并深入了解可能的 大类的遗传多样性的进化途径 病毒。

Detailed computer-assisted comparative analysis of protein sequences & gene arrangement in positive-strand, negative-strand and double-stranded RNA viruses was performed in order to predict functions of gene products, to deriveprinciples of genome organization, and to propose evolutionary scenarios. RNA viruses have small genomes and complete genome sequences representative of the majority of known groups of these viruses are currently available allowing for large-scale comparative and evolutionary studies. Positive-strand RNA viruses have a limited number of conserved proteins that are mostly involved in genome replication and expression. Two types of putative methyltransferase domains, one of which is conserved in viruses of the alpha-like supergroup, and the other in flaviviruses, have been identified. Domain organization of Hepatitis E virus polyprotein was explored in detail and it was shown that this virus is related to Rubella virus and to Beet necrotic yellow vein virus, a plant furovirus. Evolution of these viruses appeared to involve several genome rearrangement events. Putative papain-like protease domains were identified in the polyproteins of each of these viruses. Analysis of the genome of Beet yellows closterovirus revealed a unique gene organization, with genes coding for proteins related to the respective proteins of two distinct groups of positive-strand RNA viruses, and to cellular heat shock proteins. It was shown that the coat protein gene of this virus is duplicated. This is the first example of coat protein gene duplication in viruses with elongated particles. A general concept of evolution of positive-strand RNA viruses based on the interplay between conservation of gene arrays and gene module shuffling is being developed. Work on summation of the information on virus genome organization and derivation of evolutionary schemes is in progress. Comparison of the sequences of proteins encoded by double-stranded RNA showed very limited conservation. The only sequence conserved among different groups was that of a domain of the RNA-dependent RNA polymerase. This sequence is distantly related to the polymerases of positive-strand RNA viruses. Phylogenetic analysis suggested that double-stranded RNA viruses may not be a monophyletic group. Different groups of double-stranded RNA viruses could have evolved from distinct groups of positive-strand RNA viruses. The significance of the project lies in the unique opportunity to compare the organization of a large number of complete genomes with varying degree of similarity to each other and to gain insight into the possible pathways of evolution of the genetic diversity of vast classes of viruses.