BEND6 promotes RNA viruses' replication by inhibiting innate immune responses.

Innate immunity serves as a crucial defense mechanism against invading pathogens, yet its negative regulatory network remains under explored. In this study, we identify BEN domain-containing protein 6 (BEND6) as a novel negative regulator of innate immunity through a genome-scale CRISPR knockout screen for host factors essential for viral replication. We show that BEND6 exhibits characteristics of an interferon-stimulated gene (ISG), with its mRNA and protein levels upregulated by RNA virus-induced IFN-β. BEND6 targets IRF3 and inhibits its recruitment by TBK1, thus preventing IRF3 phosphorylation and dimerization. Additionally, BEND6 directly binds to ISRE, thereby hindering the DNA binding activity of IRF3 and blocking the subsequent activation of IFN-β transcription. Taken together, our study reveals the mechanism of BEND6 in promoting the replication of various RNA viruses and provides a potential therapeutic target for RNA virus infection.