肠道病毒71型毒力位点影响病毒增殖的机制研究

Virulent EV71 can be associated with severe neurological disease and significant mortality, for which there is currently no effective therapy and vaccine. The genomic determinant for EV71 neurovirulence remains unexplored. In our preliminary study, we have confirmed VP1107 as a new virulence determinant of highly-pathogenic strain through construction of chimeric and site-directed mutagenesis strains between two EV71 infectious clones (pEV71-HP and pEV71-CCA) with different proliferation phenotypes. At this site, the solo amino acid substitution of Ala to Thr will significantly inhibit the virus proliferation. In this proposed work, based on the preliminary data, we will first investigate the biological function of VP1107 during the early stage of post-attachment and define the key involved step of viral life cycle. Then we will further explore the mechanism how VP1 107 influences the virus proliferation from two aspects respectively: the structure of the viral protein and the interaction between virus and host. The objective of this work is to promote the development of novel anti-EV71 drugs and effective vaccines.

高致病性EV71毒株的感染易伴发神经系统症状，是导致手足口病死亡病例的主要原因，由于目前临床上仍缺乏防治EV71感染的药物及疫苗，因而EV71毒力位点及其机制的研究对于手足口病的诊断和防治有着重要的应用价值。我们的前期工作发现VP1107是EV71高致病性毒株的新毒力位点，该位点参与病毒吸附后早期阶段中的关键环节。本课题拟依据前期工作基础，深入研究毒力位点VP1107在病毒吸附后早期阶段中的生物学功能，明确其参与的病毒生活周期关键环节，并分别从病毒蛋白结构和病毒宿主相互作用两方面探索其作用机制。本课题的研究将为阐明EV71高致病性毒株的致病机理、研发抗病毒药物的新靶点及筛选安全有效的疫苗株提供理论依据。

肠道病毒71（EV71）是临床上引起儿童手足口病的主要病原,可以导致严重的并发症甚至死亡。该项目主要研究了EV71结构蛋白VP1第107位保守氨基酸A对于病毒复制的影响。该位点氨基酸残基的突变能够显著影响病毒的复制动力学曲线，但并不影响病毒的进入，病毒的原位复制和病毒的释放。进一步的机制研究发现VP1A107可以调节VP0前体蛋白的剪切效率影响病毒颗粒的成熟化，进而影响下一轮病毒复制时的脱衣壳过程。VP1A107周围结构域的分子动力模拟和氢键网络分析发现VP1蛋白BC环的柔性与病毒的感染性直接相关。该区域足够的结构柔性是VP0前体蛋白剪切及后续脱衣壳过程所需要的。我们的研究发现了高度保守的VP1A107位点可以调节EV71病毒颗粒的成熟化，为阐明肠道病毒发病机制提供了理论基础。

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