PA基因在禽流感病毒跨宿主感染中的作用研究

The preliminary studies supported by the National Natural Science Funds for Young Scholar mainly investigated the biological characteristics of H9 subtype reassortants of avian influenza virus. Five research articles based on these work have been published in peer-reviewed journals（3 out of 5 articles were published as first/joint first author）, with total impact factor of 23.599 and times cited of 16. The preliminary studies revealed that human PA subunit perhaps had a critical role in increasing the infectivity of avian influenza viruses in human, and some avian H9-pandemic reassortants possessing the PA gene of H1N1/2009 origin could emerge with a potentially higher threat for humans. According to above discovery, we plan to analyze the effect of PA subunits from different species in enhancing the infectious ability and adaptability of avian influenza virus in the corresponding host. Therefore, in the proposed studies, we will replace the PA subunit of avian influenza virus with the PA subunit derived from different host species, such as human, swine and canine, by using the reverse genetics manipulation. After the gene replacement, we propose to analyze the polymerase complex activity, virus replication and infectious ability in different host cells and animal models. The experiments proposed will provide comprehensive insight into the role of the PA subunit in interspecies infection of avian influenza viruses, and early warning information of the emergence of novel avian influenza reassortants in important animals and human.

在青年科学基金项目支持下，课题组主要开展了H9亚型重排禽流感病毒的生物学特性研究，发表SCI论文5篇（申请人以第一/并列第一发表3篇），累计影响因子23.599，他引次数16次。在研究中，我们发现H1N1/2009人甲型流感病毒PA基因的替换可能提高禽流感病毒对人的感染性，从而产生威胁人群的新型禽流感病毒。基于这一发现，课题组拟进一步比较人源以及不同哺乳动物源PA基因在影响禽流感病毒感染对应宿主中的作用。我们将利用反向遗传技术，以H9N2亚型禽流感病毒为骨架，分别将人、猪和犬等不同宿主来源的PA基因与禽流感病毒的PA基因进行替换，比较基因替换病毒的聚合酶复合物活性，以及在不同宿主细胞及动物模型上的复制性和感染力，从而综合评价不同宿主来源PA基因在禽流感病毒跨种间感染和传播中的作用及相关性，为新型禽流感病毒在重要动物及人群间的大流行提供分子预警信息。

在青年-面上项目资助下，主要开展了PA基因在禽流感病毒跨宿主感染中的作用研究。在Journal of Virology杂志发表SCI论文2篇，累计影响因子9.212，他引次数12次。在研究中，利用反向遗传操作技术，分别将人源和猪源流感病毒PA基因插入禽流感病毒的基因组中，构建PA基因替换病毒。研究发现人源和猪源流感病毒PA基因与禽流感病毒的基因兼容性均较好，增强了禽源病毒聚合酶活性。同时发现，PA基因356位宿主特异性位点的人样突变提高了H9N2亚型禽流感病毒对哺乳动物的感染性；PA-P224S与PA-A70V适应性突变位点有助于增强H1N1/2009流感病毒对小鼠的致病性。这些研究结果有助于全面理解PA基因在禽流感病毒跨种间感染中的作用，为预警禽流感病毒在人以及哺乳动物间的传播和流行提供理论依据。