Processing of double-stranded RNA in Mammalian cells: a direct antiviral role?

Processing of viral double-stranded RNA (dsRNA) into small interfering RNAs (siRNAs) contributes directly to an antiviral effect in plants and invertebrates, which is amplified through the recruitment of RNA interference (RNAi). In mammals, viral dsRNAs are the substrate of the innate immune response and limit viral spread by impacting on cellular translation and cytokine production, as well as promoting cell death. Recent studies suggest that viral siRNAs also exert a direct antiviral activity in mammalian cells. Here, I review the current knowledge of dsRNA processing in mammalian cells and discuss the recent findings in light of the complex interplay between RNAi and dsRNA-driven innate immune responses toward the common goal of virus restriction.