White spot syndrome virus hypothetical protein GP017 functions as a putative RNA interference suppressor

This is the authors' abstract. We don't add key points for this paper.

White spot syndrome virus (WSSV) causes severe economic losses globally. Although RNA interference (RNAi) is a key antiviral defense in crustaceans, the co-existence of WSSV mRNA and siRNA observed in Fenneropenaeus chinensis during acute infection suggests dysfunction of the RNA-induced silencing complex. This led us to investigate whether WSSV encodes viral suppressors of RNAi (VSRs) to counteract host RNAi pathways at this stage. Through an integrated computational and experimental approach, we identified a hypothetical protein of WSSV, GP017 (YP_009220491.1), as a potential VSR. Computational docking revealed a potential interaction between GP017 and shrimp Argonaute 2 (AGO2), a core RNAi component. A mammalian cell-based reversal-of-silencing assay demonstrated that GP017 restored GFP expression by suppressing RNAi-mediated silencing in HEK293T cells, with an efficacy comparable to that of the well-characterized VSR P19. Furthermore, yeast 2-hybrid and bimolecular fluorescence complementation assays confirmed an interaction between GP017 and shrimp AGO2, supporting its role as a VSR. Bioinformatic analyses suggest a coordinated regulatory model for gp017, in which viral proteins WSV500 and WSV083 may interact with high-potential promoter regions. These findings provide the initial evidence of a WSSV-encoded VSR, offering insights into viral immune evasion and potential targets for antiviral strategies in shrimp aquaculture.