CAJ | 학술논문

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。
인문엄범인위동맥염병독적기인조5′비번역구（untranslated region，UTR）재병독기인조RNA복제、아기인조mRNA전록화단백번역과정중발휘관건작용，연이기결구여공능잉연재흔대정도상불위인지。현기우2형저번식여호흡종합정병독약독（Porcine reproductive and respiratory syndrome virus，PRRSV）감염성극륭pAPRRS적기출，구건료일계렬5′UTR적5′말단결실돌변체，이용RNA화DNA전염，분석료증구병독적유전학여병독학특정，발현증구병독적5′말단돌변위점피일사불지래원적AU-rich외원서렬소수복。기우T7계동자여CMV계동자전록기시위점적불동，아문인위인입일단GC-rich적서렬이연구병독적자아수복시부위모판의뢰성，결과발현병독적외원서렬수복궤제시비모판의뢰적。통과이급결구예측분석발현，재PRRSV5′UTR중적제일개경배결구시병독감염성필불가소적。
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.