[Drosophila antiviral innate immunity]

Genetic analysis of the drosophila antiviral response indicates that RNA interference plays a major role in the control of viral infections. This involves the sensing of viral double stranded RNA by Dicer-2, which generates 21nt small interfering (si)RNAs. These siRNAs are then loaded onto the effector enzyme Argonaute-2, and guides towards RNA molecules containing complementary sequences. An inducible antiviral response also contributes to the control of viral infections in drosophila, and involves the NF-_B pathways Toll and IMD, as well as the JAK/STAT signaling pathway. The effector molecules regulated by these pathways, as well as the sensors of viral infection triggering them remain poorly characterized. In spite of these uncertainties, it is nowwell-established that drosophila is a powerful model to decipher evolutionary conserved mechanisms of antiviral host-defense, in particular in mosquito vectors of arboviruses.