Interaction of the surface protein with a novel pro-viral protein from .

Unlabelled: Dengue virus (DENV) and other flaviviruses are prevented from replicating in mosquitoes by . To date, several reports have appeared that highlight multiple molecular and cellular pathways involved in the blocking mechanism, which underlines the complicated nature of the mechanism. Here, we developed a hypothesis on whether proteins interact with pro-viral host proteins by using a unique approach to study the antiviral mechanism based on -host protein-protein interaction. We selected surface protein (WSP) for co-immunoprecipitation because of its abundance and possible secretion. We first confirmed WSP's secretion in mosquito cells and found two host proteins, serine-threonine kinase (STK) and synaptic vesicle membrane (SVM) protein VAT-1, and one protein (GroEL) interacting with WSP. We examined the role of and genes in relation to DENV replication in mosquitoes and mosquito cell lines with and without . In DENV-infected Aag2 cells, the expression of and was significantly increased. However, although these genes were induced in -infected Aag2 cells, they were downregulated after DENV infection. Silencing of , but not , reduced DENV replication in Aag2 cells and mosquitoes. Conversely, RNA activation of , by utilizing promoter induction via short activating oligos, resulted in higher DENV replication in -infected and uninfected cell lines. Overall, our findings suggest that is a pro-viral gene, and WSP binds to STK, possibly making it less accessible for DENV replication.

Importance: is an endosymbiotic bacterium that blocks the replication of arboviruses in transinfected mosquitoes. In this study, we focused on identifying the potential interaction of proteins with the host pro-viral proteins. For this, we embarked on identifying the interacting proteins with a major protein, WSP, which is both structural and also secreted into the host cells. An STK was identified, which is induced in DENV and -infected cells. Silencing or induction of the gene led to reduced and increased DENV replication . Consistently, knocking down the gene in mosquitoes resulted in decreased virus replication. We hypothesize that WSP may sequester STK, which is pro-viral, contributing to virus blocking.