鼻病毒C型5’端非编码区和2A蛋白的协同作用

The interaction between 5' UTR region and protein is an essential point in the study of rhinovirus replication. Our previous results showed the high diversity and recombination events in the 5' UTR region and 2A proteinase of the newly discovered rhinovirus species C, but the biological signification of this phenomenon is unclear. As 5' UTR needs to fix to cellular factors to realize it's biological function, and with the progress in the study of interaction between viral 2A protein and host factors, we propose here a hypothesis: the RNA secondary structure of rhinovirus C in 5'UTR region is changed due to the mutations, whereas 2A proteinase of rhinovirus C has an affinity and/or a cleavage products' profile different from rhinovirus species A and species B. The changes together cause that the affinity of 5'UTR with cellular translation factors which are cleaved by 2A proteinase changes or 5' UTR fix to different cellular factors. It induces the change in virus replication. In this study, a set of mosaic infectious clones composed by the sequences of 5' UTR, structure proteins and non-structure proteins from three species of HRV will be constructed in different combinations by using reverse genetic method. The replications of different chimeric HRV and their mutants in cell and mouse models will be compared, in order to verify the synergy between 5' UTR and 2A protein in the replication of rhinovirus C. This study will interpret the mechanism for the changes in virus replication and virulence of rhinovirus C, provide a clue to further study of the interaction between 5' UTR and host cellular factors cleaved by 2A protein, and be benefit for the antiviral study of rhinovirus.

5'端非编码区与蛋白相互作用是鼻病毒复制研究的关键问题。本研究前期发现5'端非编码区和非结构蛋白2A是新C型鼻病毒基因变异重组的热点区，但该现象的生物学意义尚不明确。已知5'端非编码区需结合细胞因子实现功能，根据2A蛋白对宿主细胞因子作用的研究进展，本项目提出假说：C型鼻病毒序列变异引起5'非编码区RNA二级结构和2A蛋白酶的亲和力或酶解产物变化，两者协同导致5'非编码区与2A蛋白酶解后的细胞翻译因子结合力改变或者结合不同因子，影响病毒复制。为验证该假说，拟用反向遗传技术构建一组由鼻病毒各型的5'端非编码区、结构蛋白以及非结构蛋白序列交叉组合而成的嵌合病毒感染性克隆及其突变株，在细胞和小鼠水平上比较不同病毒株的复制情况。本项目为探索鼻病毒复制和毒力变化的作用机制以及下一步鼻病毒5'端非编码区与2A蛋白酶解后的细胞因子的相互作用提供研究思路，为鼻病毒感染的药物研发提供靶点。