Proteomic analysis reveals vector-virus interactions between Zika virus and Aedes aegypti mosquito cells

Zika virus (ZIKV) is an arbovirus (family Flaviviridae) mainly transmitted by Aedes mosquitoes causing febrile illness and Zika congenital syndrome in infants if mothers were infected during pregnancy. ZIKV manipulates its host’s cellular machinery in order to facilitate infection and evade antiviral responses. The identification of host and vector proteins involved in these processes may lead to novel antiviral strategies. In this study, Ae. aegypti cell lines (AF5) stably expressing V5-tagged ZIKV capsid (C) or anchored capsid (AC) proteins were developed to investigate virus-vector protein interactions. To identify interaction partners, immunoprecipitation (IP) of V5-tagged C or AC was performed and subjected to proteomic analyses using nLC-MS/MS under label-free quantification conditions. A total of 148 and 53 mosquito protein interactors unique to C and AC were identified, respectively. Protein network and gene ontology analyses showed biological processes possibly important for ZIKV infection. To investigate further the role of these proteins during infection, 25 were chosen for dsRNA-based knockdown screen and infection with reporter virus (ZIKV-Nluc) in AF5 cells. Significant reduction in reporter virus signal was observed during knockdown of 6 interactors suggesting a pro-viral role for these proteins during infection. This was corroborated by conducting the same knockdown experiments but infecting with a clinical isolate of ZIKV (PE243), which showed reduced virus RNA levels and titre. Interestingly, three of the six proteins are part of the ubiquitin-proteasome pathway (UPP). Currently, functional experiments are underway to investigate the role of UPP during ZIKV infection.