口蹄疫病毒5'UTR的假结节结构影响宿主嗜性的分子机制

宿主嗜性变异一直是病毒学研究的一个热点和难点问题，口蹄疫病毒除了已被证明O型Cathay谱系毒株是适应猪毒株外，还出现了其它毒株从牛羊感染逐步适应到猪的临床现象。我们的前期研究证明，除了3A缺失导致对猪适应变异外，假结节（PK）结构的缺失是口蹄疫病毒适应猪新的决定因素。为了阐明口蹄疫病毒适应猪背后新的分子机制，本项目通过反向遗传操作、RNA与蛋白互作、基因编辑等技术，在细胞和宿主水平，鉴定不同PK结构对病毒复制、致病性和宿主嗜性的作用及其功能域。筛选与PK结构互作的宿主蛋白，并确定其对病毒复制和致病性的影响；据筛选的宿主蛋白功能及其信号转导路径，开展PK结构对靶标蛋白的调控及信号转导机制研究，检测PK与宿主蛋白互作对信号通路节点蛋白转录、表达、磷酸化和泛素化的影响，检测被影响的节点蛋白下游效应分子的变化，为阐明口蹄疫病毒适应猪的宿主嗜性变异的新机制奠定基础。

Host tropism variation has been a difficult scientific question and a hot topic in virology. It has been proved that the Cathay isolates of foot-and-mouth disease virus (FMDV) are pig-adapted strains. Besides, the other strains from cattle and sheep have been gradually adapting to pigs in field. Our previous studies have found that the deletion in pseudoknots (PKs) affected the replication and pathogenicity of FMDV. To reveal the role of PKs in host tropism variation of adaption to pigs of FMDV, we will determine the role of PKs in viral replication and pathogenicity, and identify the potential host proteins that interact with PKs using reverse genetics, RNA-protein pull-down, CRISPR-Cas9 and other methods. Furthermore, the interaction domain or regions between PKs and host proteins will be identified. The roles of the identified host proteins in the replication and pathogenicity of FMDV and the involved molecular mechanisms will be further determined. The transcripts, protein expression, phosphorylation and ubiquitination levles of the adaptor proteins in the signaling pathway and it’s downstream effective molecules that induced by PK and host protein will be analyzed. This study will provide a theoretical basis to understand the host tropism variation of adaption to pigs of FMDV as well as exploit a strategy for swine FMD control.