黄病毒组装促进内质网-脂滴互作的调控机制研究

近年全球多次爆发病毒感染疫情，但靶向病毒组装的抗病毒机制研究尚不深入。黄病毒是以丙肝和登革病毒为代表的包膜正链RNA病毒，其组装在内质网表面完成。内质网与脂滴交联互作部位的生物合成非常活跃，为病毒组装提供了理想场所。我们前期发现黄病毒在内质网-脂滴互作位置组装；丙肝病毒的core和NS3蛋白分别定位在脂滴和内质网表面；活病毒感染或外源表达病毒蛋白都能促进两个细胞器互作；此外，我们还发现宿主蛋白nestin特异与病毒的core和NS3结合；nestin缺失抑制内质网-脂滴互作并降低病毒感染效率。本项目将深入解析黄病毒感染对内质网-脂滴互作的利用性调控策略，重点是鉴定宿主蛋白在内质网-脂滴互作位置与病毒蛋白交互调控的分子网络，解析该互作对不同黄病毒组装的功能意义和异常调控细节，筛选靶向该交联互作的抗病毒小分子药物。本项目的实施将丰富对细胞器互作生物学意义的认识，加深对病毒与宿主互作过程的理解。

Virus infection caused epidemic outbreaks are increasing dramatically in recent years globally. However, the anti-viral studies target on the assembly of viruses remain elusive. Flaviviridae, including hepatitis C virus (HCV) and dengue virus (DENV), is an enveloped single strand positive sense RNA virus family. The assembly events of viral particles reside on the surface of endoplasmic reticulum (ER). Both ER and lipid droplets (LDs) are important organelles that in charge of the biosynthesis and storage of proteins and lipids. Therefore, the ER-LDs membrane contact sites (MCSs) actively display dynamic interaction. The assembly of viruses need synthesizing a large amount of proteins, nucleotides, and other molecules. At the same time, the assembly of viruses consume a large amount of ATP. Therefore, ER-LDs MCSs provide ideal loci for viruses to perform assembly processes. Our preliminary data shows that: HCV core and NS3 protein localize on the surface of LDs and ER, respectively; the assembly sites of HCV particles locate on the ER-LDs MCSs; viral infection and viral protein expression increase the ER-LDs interaction; moreover, host protein nestin specifically interacts with HCV core and NS3; depletion of nestin suppresses the ER-LDs interaction and further leads to reduce the viral infection. Next, we will focus on the regulation of ER-LDs MCSs during flavivirus infection, study the hijack strategy of flavivirus infection to the host ER-LDs interaction; explore the host-viral protein network on the ER-LDs MCSs; analysis the functional significance and dysfunctional regulation of the ER-LDs interaction to the assembly events of distinct flaviviruses; establish screen and identify clinical moleculars targeted to ER-LDs MCSs which potentially can be used as anti-viral drugs. Successful implementation of this proposal will improve our understanding on the interaction network of organelles. With these cell biological studies, it will also provide a novel insight into the viral-host interaction mechanisms.