TY - JOUR T1 - Loquacious Modulates Flaviviral RNA Replication in Mosquito Cells JF - bioRxiv DO - 10.1101/2021.12.03.471060 SP - 2021.12.03.471060 AU - Shwetha Shivaprasad AU - Kuo-Feng Weng AU - Yaw Shin Ooi AU - Julia Belk AU - Jan E. Carette AU - Ryan Flynn AU - Peter Sarnow Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/12/03/2021.12.03.471060.abstract N2 - Arthropod-borne viruses infect both mosquito and mammalian hosts. While much is known about virus-host interactions that modulate viral gene expression in their mammalian host, much less is known about the interactions that involve inhibition, subversion or avoidance strategies in the mosquito host. A novel RNA-Protein interaction detection assay was used to detect proteins that directly or indirectly bind to dengue viral genomes in infected mosquito cells. Membrane-associated mosquito proteins SEC61A1 and Loquacious (Loqs) were found to be in complex with the viral RNA. Depletion analysis demonstrated that both SEC61A1 and Loqs have pro-viral functions in the dengue viral infectious cycle. Co-localization and pull-down assays showed that Loqs interacts with viral protein NS3 and both full-length and subgenomic viral RNAs. While Loqs coats the entire positive-stranded viral RNA, it binds selectively to the 3’ end of the negative-strand of the viral genome. In-depth analyses showed that the absence of Loqs did not affect translation or turnover of the viral RNA but modulated viral replication. Loqs also displayed pro-viral functions for several flaviviruses in infected mosquito cells, suggesting a conserved role for Loqs in flavivirus-infected mosquito cells.Author Summary There is a wealth of information that dictates virus-host interactions in flavivirus-infected mammalian cells, yet there is only sparse information on the mechanisms that modulate viral gene expression in the mosquito host. Using a novel RNA-protein detection assay, the interactions of SEC61A1 and Loqs with the dengue viral genome were found to have proviral functions in infected mosquito cells. In particular, Loqs forms complexes with the positive-strand of the viral RNA and the very 3’ end of the negative-strand viral RNA. Further analyses showed that Loqs modulates viral RNA replication of dengue virus and gene amplification of several other flaviviral genomes. These findings argue that Loqs is an essential proviral host factor in mosquitos.Competing Interest StatementThe authors have declared no competing interest. ER -