Identification of Viral Suppressors of RNAi by a Reporter Assay in Drosophila S2 Cell Culture

The RNA interference (RNAi) pathway plays an important role in antiviral immunity in insects. To �counteract the RNAi-mediated immune response of their hosts, several insect viruses, such as Flock house virus, Drosophila C virus, and Cricket paralysis virus, encode potent viral suppressors of RNAi (VSRs). Because of the importance of RNAi in antiviral defense in insects, other insect viruses are likely to encode VSRs as well. In this chapter, we describe a detailed protocol for an RNAi reporter assay in Drosophila S2 cells for the identification of VSR activity.