Pirh2介导的核蛋白NP泛素化修饰在IAV感染中的作用机制

甲型流感病毒（IAV）极易突变，难以防治。IAV的RNA聚合酶控制病毒基因组转录与复制，是决定病毒感染和宿主嗜性的关键因子。因其相对保守，而成为了抗病毒新靶标。蛋白翻译后修饰(PTM)在IAV感染周期中起重要作用，但PTM如何调节RNA聚合酶功能尚不清楚。我们发现，核蛋白NP可能是E3泛素连接酶Pirh2的泛素化修饰底物。因此，本项目拟研究IAV感染与Pirh2的互作。首先，研究IAV感染调控Pirh2蛋白表达的机制；然后，研究改变Pirh2的表达对IAV感染与复制的影响；最后，从Pirh2介导的泛素化修饰对NP蛋白稳定性、亚细胞定位、结合PB2或RNA的能力，以及RNA聚合酶活性等影响，阐明Pirh2对NP蛋白的调节机制。这不仅有助于了解Pirh2介导的泛素化修饰对IAV感染与复制的调节机制，为发现靶向RNA聚合酶的抗病毒靶点提供理论依据，而且能为PTM对IAV的调节作用研究提供参考。

Influenza A virus (IAV) is highly susceptible to mutation and is difficult to control. IAV's RNA polymerase controls viral genome transcription and replication and is a key factor in determining viral infection and host tropism. Because of its relatively conservative, it has become a new anti-viral target. Protein post-translational modification (PTM) plays an important role in the IAV infection cycle, but how PTM regulates RNA polymerase function is not clear. We found that nucleoprotein NP is a potential substrate of Pirh2 E3 ligase and modified by ubiquitination. Therefore, we propose to study the interaction between IAV infection and Pirh2. Specifically, we will study the mechanism by which IAV infection regulates Pirh2 expression. Conversely, we will examine the effect of altered expression level of Pirh2 on IAV infection and replication. Finally, we will characterize the effect of Pirh2-mediated NP ubiquitination on NP protein stability, subcellular localization, binding to PB2 or RNA, as well as RNA polymerase activity, to uncover the regulatory mechanism of Pirh2 on NP protein. This study will not only help to understand the regulatory mechanism of Pirh2-mediated ubiquitination on IAV infection and replication and provide a theoretical basis for the discovery of antiviral candidates targeting RNA polymerase, but also serve as a valuable example for studying the role of PTM in IAV infection.