PABPC1影响甲型流感病毒复制的分子机制研究

As we know, virus replication efficiency in infected cells is a combat between virus and the cells, the outcome of the infection is diversified by multi-dimensional interactions between virus and host factors. In particular, influenza A virus transcribes and replicates its genome in the nucleus of infected cell. Therefore, more interactions between host factors and viral factors are involved in modulating virus replication efficiency. In this project, through Co-IP followed mass spec analysis and siRNA screening, we newly identified a host factor PABPC1 acting as a negative regulator by differentially regulating virus protein expressions. More interestingly, we found that the viral protein NS1 could antagonize the effects of PABPC1 upon influenza A virus infection. Based on this new finding, we will focus on studying the differential effects of PABPC1 on regulation of viral mRNA synthesis, splicing, translocation, translation and stabilities etc. Furthermore, we will elucidate by which molecular mechanism(s) that the NS1 specifically antagonizes the PABPC1 effects upon influenza A virus infection. These studies will further our understanding of the molecular interactions between host cell and influenza virus, and could ultimately provide ideas for the development of new antiviral drugs.

我们知道，病毒在细胞中复制能力取决于病毒与宿主细胞之间的博弈能力，即体现在病毒与宿主因子相互作用的差异，特别是针对甲型流感病毒在宿主细胞核中进行病毒基因组转录与复制，因此会有更多的宿主因子和病毒因子的相互作用来参与调控二者之间的博弈。我们通过前期质谱分析和siRNA筛查，首次发现PABPC1可调控甲型流感病毒特异蛋白的表达来负向调控病毒复制，更有意思的是，我们发现病毒编码蛋白NS1可拮抗PABPC1对流感病毒复制的负调控作用。基于此新发现，我们将针对PABPC1可能差异影响病毒mRNA合成、剪接、出核、翻译和稳定性等各个过程来深入探究。在此基础上，我们还要进一步详细阐明NS1是如何拮抗宿主PABPC1作用的分子机制。研究结果不仅会深化我们对宿主因子在流感病毒RNA转录与复制中作用的认识，并会为开发新型抗病毒药物提供新思路。

甲型流感病毒（Influenza A Virus）是分节段的单负链RNA病毒，能够造成人类季节性流感流行和大流感爆发。病毒在细胞中复制能力取决于病毒与宿主细胞之间的博弈能力，体现在病毒与宿主因子相互作用的差异，特别是针对甲型流感病毒在宿主细胞核中进行病毒基因组转录与复制，会有更多的宿主因子和病毒因子的相互作用来参与调控二者之间的博弈。.通过蛋白的亲和纯化，我们筛选到了48个同流感病毒的非结构蛋白NS1有相互作用的宿主因子，并首次发现PABPC1（Poly(A) Binding Protein， Cytoplasmic 1）是具有负调控作用的宿主因子，可调控甲型流感病毒特异蛋白的表达，对病毒HA和NA蛋白的表达的抑制作用最为明显。进一步研究发现，在病毒感染状态下PABPC1和病毒蛋白NS1、NP的相互作用是依赖于RNA介导的。在流感病毒RNP重组系统中，PABPC1通过与NP相互作用抑制流感病毒的vRNP的装配，从而影响病毒vRNA的合成。另外，PABPC1显著抑制病毒HA mRNA在内质网上的翻译过程，而NS1可以拮抗PABPC1对病毒HA mRNA在内质网上翻译过程的负调控作用。以上研究结果不仅会深化我们对宿主因子在流感病毒RNA转录、复制和翻译过程中作用的认识，并会为开发新型抗病毒药物提供新思路。