Viral suppressors of RNA-based viral immunity: host targets

Abstract

RNA-based viral immunity (RVI) operates in fungi, plants, and invertebrates to specifically destroy viral RNAs using the cellular RNA interference machinery. Discovery of diverse viral proteins as suppressors of RNA silencing provides strong validation for the effectiveness of RVI. Here we review recent studies that have revealed new mechanistic insights into plant and insect viral suppressors of RVI or suggested a role for RNA silencing suppression during mammalian viral infection.

Fig. 1

Mechanisms in the viral suppression of RNA-based viral immunity. VSRs target RNA and protein components of the RNA silencing pathway and inhibit siRNA production (B2, P6), RISC assembly (P0 and possibly P38), slicing activity of mature RISC (P1, 1A), amplification of viral secondary siRNAs (2b, RNaseIII (R3), V2), or intercellular movement of viral siRNAs (P19).