A Vago-like gene enhances dengue and Zika virus dissemination in Aedes aegypti

Arthropod-borne viruses (arboviruses) such as dengue virus (DENV) and Zika virus (ZIKV) pose a significant threat to global health. Novel approaches to control arbovirus spread are focused on harnessing the antiviral immune system of their main vector, the Aedes aegypti mosquito. In arthropods, genes of the Vago family are often presented as analogs of mammalian cytokines with potential antiviral functions, but the role of Vago genes upon virus infection in Ae. aegypti is largely unknown. We performed a phylogenetic analysis of the Vago gene family in Diptera that prompted us to focus on a Vago-like gene that we named VLG-1. Using CRISPR/Cas9-mediated gene editing, we generated a VLG-1 mutant line of Ae. aegypti that revealed a proviral effect of this gene upon DENV and ZIKV infection. In the absence of VLG-1, virus dissemination throughout the mosquito's body was impaired, albeit not altering virus transmission rates. A tissue-specific transcriptome analysis revealed that the loss of VLG-1 impacted numerous biological processes potentially linked to viral replication, such as the oxidative stress response. Our results challenge the conventional understanding of Vago-like genes as antiviral factors and underscores the need for further research to elucidate the molecular mechanisms underlying mosquito-arbovirus interactions. Overall design: To investigate the global impact of VLG-1 loss and its link with virus infection in Ae. aegypti, we analyzed the midgut and body (carcass + head) transcriptomes of VLG-1? mutant and control lines on days 2, 5, and 9 after a DENV-1 or mock bloodmeal. Each RNA-Seq library is a pool of 10 individual tissues.