Yann Desfossés, Institut national de la recherche scientifique

Clément Mazeaud (Institut national de la recherche scientifique), Laurent Chatel-Chaix (Institut national de la recherche scientifique)

Expressing & Multiplying

Zika virus (ZIKV) is responsible for multiple epidemics, and is vertically transmissible, causing different neurodevelopmental defects. Despite this, no drugs or vaccines are currently available, therefore underlying the importance of identifying new antiviral targets. Cytoplasmic replication of viral RNA (vRNA) relies on endoplasmic reticulum remodeling. Our team previously showed that IGF2BP2, a host RNA binding protein, regulates replication by associating with the 3' UTR of vRNA and NS5 polymerase, and promoting the biogenesis of viral replication organelles. However, IGF2BP2 and vRNA domains implicated in this interaction remain unknown. IGF2BP2 is composed of 6 RNA binding domains (RBD), and its phosphorylation is important for RNA binding. Furthermore, ZIKV infection alters the proteo-interactome of IGF2BP2, suggesting that partners with modified association might have pro- or anti-viral properties. Lentiviruses encoding HA-tagged IGF2BP2 mutants will be generated to investigate (1) the RBD responsible for vRNA interaction and (2) the contribution of IGF2BP2 phosphorylation in viral replication in Huh7 cells by co-IP followed by RT-qPCR, and plaque assays and RT-qPCR respectively. Subsequently, the IGF2BP2-bound vRNA region will be identified by HITS-CLIP in infected cells expressing IGF2BP2-HA. Finally, Huh7 cells will be knocked-down for each modulated IGF2BP2 partner, then infected with luciferase-expressing viruses in order to identify partners that modulate replication. These partners will be further characterized to identify the steps of the viral cycle that they regulate. This study will contribute to understand the role and the determinants of the IGF2BP2 ribonucleoprotein complex in ZIKV life and may identify new antiviral targets.