柞蚕传染性软腐病病毒(Iflavirus)功能蛋白的基因克隆和结构分析

Gene Cloning and Structure Analysis of Functional Proteins from Iflavirus of Antheraea pernyi

从患柞蚕吐白水软化病的病蚕体内分离到一株传染性软腐病病毒属(Iflavirus)病毒。研究柞蚕传染性软腐病病毒基因组结构及主要功能蛋白的结构域,为确定该病毒株的分类学地位和阐释其侵染机制提供基础信息。克隆了编码柞蚕传染性软腐病病毒功能蛋白的RNA解旋酶基因(423 bp)、3C半胱氨酸蛋白酶基因(405 bp)以及RNA依赖性的RNA聚合酶基因(882 bp)。通过同源模建方法,构建了柞蚕传染性软腐病病毒3个功能蛋白的三维结构模型,并采用拉氏图和Profile 3D等方法验证了模型的可靠性。将柞蚕传染性软腐病病毒中RNA依赖性的RNA聚合酶序列与另外16个小RNA病毒同源序列进行比对并构建系统发育树,显示柞蚕传染性软腐病病毒与蜜蜂残翅病病毒和蜜蜂瓦螨虫病毒的亲缘关系十分相近。

In this study,an Iflavirus isolate（ ApIV） was obtained from dead larvae of Antheraea pernyi infected by vomiting-type flacherie. Its genome structure and main functional proteins＇ structural domains were analyzed so as to provide basic references for understanding its taxonomical status and infection mechanism. Genes coding for RNA helicase（ 423bp）,3C cysteine protease（ 405 bp）,and RNA-dependent RNA polymerase（ 882 bp） of ApIV were cloned. Through homology modeling,three-dimensional structures of these 3 functional proteins were established. Moreover,reliability of the structural models was tested and verified by Ramachandran plot and Profile 3D. The highly conserved motifs of RNAdependent RNA polymerase amino acid sequences from ApIV and 16 other viruses of the picorna-like superfamily were used to construct phylogenetic tree,which indicated that ApIV had close relationship with the deformed wing virus and Varroa destructor virus-1 of Apis mellifera.