Proteomics Analysis Of Virion And Virus-host Interactions

Viral proteomics refers to studies of virion proteome and large scale analysis of virus-host interactions at protein level. By using a combination of different proteomics strategies, we compared the proteome of the two phenotypes of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) and systematically analyzed proteome changes in JEV-infected HeLa cells.During life cycle, baculoviruses will produce two progeny phenotypes:the occlusion derived virus (ODV) and the budded virus (BV). ODV establishes infection in midgut cells, while BV disseminates infection to different tissues within the susceptible host. We employed multiple proteomic methods to reveal protein composition, localization and post-translational modifications of the two phenotypes of Helicoverpa armigera nucleopolyhedrovirus. Comparative protein portfolios of BV and ODV showing the distribution of54proteins from77identified protein. While the proteins shared by the two phenotypes appear to be important for nucleocapsid assembly and trafficking, the structural and functional differences between the two phenotypes are evidently characterized by the envelope proteins and post-translational modifications:ODV specific proteins are important for oral infection; while BV specific proteins are important for membrane fusion. Our comparative proteomics study provides new insight into why BV and ODV function differently.Japanese encephalitis virus (JEV) enters host cells via receptor-mediated endocytosis and replicates in the cytoplasm of infected cells. To study virus-host cell interactions, we performed a SILAC-based quantitative proteomics study of JEV-infected HeLa cells using a subcellular fractionation strategy. We identified158host proteins as differentially regulated by JEV (defined as exhibiting a greater than1.5-fold change in protein abundance upon JEV infection). Bioinformatics analyses indicated the JEV infection-induced host response was found to be coordinated primarily through the immune response process, the ubiquitin-proteasome system (UPS), the intracellular membrane system, and lipid metabolism-related proteins. Protein functional studies of selected host proteins using RNA interference-based techniques were carried out in HeLa cells infected with an attenuated or a highly virulent strain of JEV. We demonstrated that the knockdown of interferon-induced transmembrane protein3(IFITM3), Ran-binding protein2(RANBP2), sterile alpha motif domain-containing protein9(SAMD9) and vesicle-associated membrane protein8(VAMP8) significantly increased JEV replication. These results not only promote a better understanding of the host response to JEV infection but also highlight multiple potential targets for the development of antiviral agents.