猪繁殖与呼吸综合征病毒5'非翻译区中一顺式结构因子对病毒感染必要性的分析  

ANALYSIS OF A CIS-ACTING STRUCTURAL ELEMENT IN THE 5' UNTRANSLATED ELEMENT OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS

作　　者：高飞[1] 陆嘉琦[1] 袁世山[1] 童光志[1] 

机构地区：[1]中国农业科学院上海兽医研究所,上海200241

出　　处：《中国动物传染病学报》2012年第1期1-9,共9页Chinese Journal of Animal Infectious Diseases

基　　金：国家自然科学基金面上项目(30972204);欧盟"第七框架"项目(245141)

摘　　要：人们广泛认为动脉炎病毒的基因组5'非翻译区(untranslated region,UTR)在病毒基因组RNA复制、亚基因组mRNA转录和蛋白翻译过程中发挥关键作用,然而其结构与功能仍然在很大程度上不为人知。现基于2型猪繁殖与呼吸综合征病毒弱毒(Porcine reproductive and respiratory syndrome virus,PRRSV)感染性克隆pAPRRS的基础,构建了一系列5'UTR的5'末端缺失突变体,利用RNA和DNA转染,分析了拯救病毒的遗传学与病毒学特征,发现拯救病毒的5'末端突变位点被一些不知来源的AU-rich外源序列所修复。基于T7启动子与CMV启动子转录起始位点的不同,我们人为引入一段GC-rich的序列以研究病毒的自我修复是否为模板依赖性,结果发现病毒的外源序列修复机制是非模板依赖的。通过二级结构预测分析发现,在PRRSV5'UTR中的第一个茎环结构是病毒感染性必不可少的。It is believed that the 5＇ untranslated region （UTR） of equine arthritis virus plays a critical role in viral genomic replication, subgenomic mRNA transcription and protein translation, yet its structure and function are still largely unknown. We constructed a number of 5＇ UTR truncated mutants based on the full-length cDNA clone pAPRRS of attenuated genotype II Porcine reproductive and respiratory syndrome virus （PPRSV）. Genetic and virologic characteristics of the rescued viruses were analyzed post RNA and DNA transfection. The truncations at the 5＇ UTRs of the revertant viruses were repaired with exogenous nucleotides of unknown origin. Because of difference in the transcriptional initiation sites for T7 and CMV promoters, we introduced a GC-rich sequence into the mutant site in order to investigate if the virus rescue was template dependent. The results showed that the repair mechanism was template independent. Further analysis of the secondary structure demonstrated that the SL1 of PRRSV 5＇ UTR was indispensable for virus infectivity.

关 键 词：非翻译区 茎环结构 回复突变体 RNA/DNA导策 

分 类 号：S852.659.6[农业科学—基础兽医学]