Published on Wed Sep 01 2021

The dengue virus non-structural protein 1 (NS1) interacts with the putative epigenetic regulator DIDO1 to promote flavivirus replication.

caraballo, g., Rosales, R., Viettri, M., Ding, S., Greenberg, H. B., Ludert, J.

Dengue virus (DENV) NS1 is a multifunctional protein essential for viral replication. To gain insights into NS1 functions in mosquito cells, the protein interactome of DENV NS1 in C6/36 cells was investigated using a proximity biotinylation system and mass spectrometry.

3
2
2
Abstract

Dengue virus (DENV) NS1 is a multifunctional protein essential for viral replication. To gain insights into NS1 functions in mosquito cells, the protein interactome of DENV NS1 in C6/36 cells was investigated using a proximity biotinylation system and mass spectrometry. Approximately 14% of the 817 identified proteins coincide with interactomes obtained in vertebrate cells, including ontology groups of the oligosaccharide transferase complex, the chaperonin containing TCP-1, and nuclear import and export, vesicle localization and ribosomal proteins. Notably, other protein pathways such as epigenetic regulation and RNA silencing, not previously reported in vertebrate cells, were also found in the NS1 interactome in mosquito cells. Due to the novel interaction observed for NS1 and DIDO1 (Death Inducer-Obliterator 1), we further explored the role of DIDO1 in viral replication. Interactions between NS1 and DIDO1were corroborated in infected C6/36 and Aag2 cells, by colocalization and proximity ligation assays. Silencing DIDO1 expression in C6/36 and Aag2 cells results in a significant reduction in DENV and ZIKV replication and progeny production. Comparison of transcription analysis of mock or DENV infected C6/36 silenced for DIDO1, revealed variations in multiple gene expression pathways, including pathways associated with DENV infection such as RNA surveillance, IMD and Toll. These results suggest that DIDO1 is a host factor involved in the negative modulation of the antiviral response and necessary for flavivirus replication. Our findings uncover novel mechanisms of NS1 to promote DENV and ZIKV replication and add to the understanding of NS1 as a multifunctional protein.