核不均一核糖核蛋白M对口蹄疫病毒复制的抑制作用及其分子机制

微RNA病毒的蛋白翻译是通过自身的内部核糖体进入位点(IRES)与宿主细胞蛋白的相互作用实现的。申请者的研究发现，IRES是口蹄疫病毒(FMDV)毒力的分子决定因素，基于IRES减毒的分子机制涉及细胞多聚嘧啶结合蛋白(PTB)与病毒IRES的相互作用，这激励我们进一步寻找与病毒IRES互作的细胞蛋白以阐明IRES突变导致FMDV减毒的精细机制。在最近的研究中我们发现，细胞中核不均一核糖核蛋白M(hnRNP M)与FMDV IRES结合，其瞬时过表达明显抑制FMDV的增殖。本研究拟确定hnRNP M与FMDV IRES的相互作用及其结合域、用敲除/过表达实验分析hnRNP M对病毒RNA合成及病毒翻译起始的调控作用、并探索hnRNP M对PTB-IRES相互作用的影响，旨在阐明hnRNP M通过结合IRES抑制FMDV复制的分子机制。这些研究，有助于了解IRES靶向FMDV减毒的精细机制。

Translation of Picornavirus proteins is performed through interaction between viral internal ribosomal entry site (IRES) and host cellular proteins. Our studies have shown that the IRES is determinant of foot-and-mouth disease virus (FMDV) virulence, and molecular mechanism of FMDV attenuation based on IRES is involved in the interaction between cellular polypyrimidine binding protein (PTB) and viral IRES. This encourages us to further explore the functional cellular proteins that interact with the IRES to elucidate the precise mechanism of IRES mutation leading to FMDV attenuation. We found in the recent study that heterogeneous nuclear ribonucleoprotein M (hnRNP M) binds to FMDV IRES, and its transient overexpression significantly inhibits the proliferation of FMDV. In this study, to elucidate the molecular mechanism of the hnRNP M to inhibit FMDV replication through binding IRES we are going to determine the interaction between FMDV IRES and hnRNP M and their binding regions, further to analyze the effect of hnRNP M on viral RNA synthesis, the IRES-mediated translation initiation, and the interaction between PTB and IRES through knockdown or over-expression of this protein gene. These results are helpful to understand the precise mechanism of IRES-targeting FMDV attenuation.