The role of cellular factor TMEM128 in flavivirus replication

Flaviviruses such as dengue virus (DENV), which is responsible for the most prevalent arboviral disease worldwide, and Zika virus (ZIKV), which can cause microcephaly in newborns through congenital transmission, constitute a major public health issue. Unfortunately, no antiviral therapy is currently available to treat these diseases. Infection with these viruses causes a spatial and morphological reorganization of mitochondria to create an intracellular environment that is favorable for viral replication. Furthermore, following mitoproteomic analysis, we recently demonstrated that TMEM128, a yet uncharacterized cellular protein, is recruited to mitochondria during flaviviral infection and positively regulates viral replication through as yet unknown mechanisms. We therefore hypothesize that TMEM128 influences ZIKV and DENV replication through its interaction with mitochondria and the regulation of their functions. First, its intracellular localization will be characterized by confocal microscopy through the overexpression of an HA-tagged version of the protein. In addition, the proviral role of TMEM128 in DENV- or ZIKV-infected cells will be confirmed by a knockout (KO) approach. The effect of overexpression of TMEM128 deletion mutants in these KO cells on the restoration of viral replication will identify the determinants of this regulation. Finally, the role of TMEM128 in the viral cycle will be studied by observing the impact of TMEM128 KO on mitochondrial morphology, induction of type I and III interferons, respiratory metabolism, apoptosis, and morphogenesis of flaviviral replication factories.