流感病毒的核输出蛋白（NEP）是病毒粒子中的结构蛋白，在病毒的基因组复制与转录、病毒vRNP复合物的细胞核输出、病毒粒子的组装、出芽等多个环节发挥着重要作用。目前，H1N1甲型流感病毒中人源WSN毒株的核穿梭机制研究已较为深入，但对猪源H1N1/CA04毒株的NEP蛋白功能的研究未见报道。前期我们对WSN和CA04两个毒株的H1N1甲型流感病毒NEP蛋白在细胞内的定位进行了比较研究，发现这两个毒株的NEP蛋白细胞内定位存在明显差异，提示不同来源毒株NEP蛋白在病毒复制的作用可能不尽相同。本研究的目的是通过比较WSN和CA04两个毒株的NEP蛋白在核定位上的差异，阐明H1N1/CA04毒株NEP蛋白的核穿梭机制，进一步确定造成NEP定位差异的机理及这种差异对NEP功能及流感病毒毒力的影响，为深入认识动物流感病毒跨种间感染的机制提供理论依据。

The nuclear export protein (NEP) of influenza virus is the structure protein in virions, playing crucial roles in the process of replication and transcription of viral genome, viral assembly, budding and nuclear export of vRNP. There has been a lot of data focused on the NEP of WSN strain of H1N1 influenza A virus. However, the detailed mechanisms of nucleocytoplasmic traffic of NEP of swine original CA04 strain remains unclear understood. Based on our data, the two different strains of H1N1 influenza A virus have displayed obvious differential location of NEP in the host cells during the viral replication. Our goal of the current proposal is to reveal the mechanism of cytoplasmic-nuclear shuttling of CA04 strain NEP of influenza A virus, compare the intracellular localization of NEP of WSN strains of influenza A virus, and determine the mechanism of the different localization of NEP and the effect on nuclear export of vRNP and virulence of influenza A virus, further understanding interspecies transmission of animal influenza A viruses.