Project description:We focus our analyses on the description of viral small RNAs (FHVdeltaB2 or FHV) and based on genetic and molecular evidende, classify them and discuss their relevance in antiviral defense. Small RNAs from adult Drosophila flies from different genetic backgrounds and infected with FHV-deltaB2 or FHV were sequenced using the illumina platform.
Project description:We focus our analyses on the description of viral small RNAs (FHVdeltaB2 or FHV) and based on genetic and molecular evidende, classify them and discuss their relevance in antiviral defense.
Project description:The fruit fly Drosophila melanogaster is a good model to unravel the molecular mechanisms of innate immunity, and has led to some important discoveries on the sensing and signalling of microbial infections. The response of drosophila to virus infections remains poorly characterized, and appears to involve two facets. On one hand RNA interference (RNAi) involves the recognition and processing of dsRNA into small interfering (si) RNAs by the host ribonuclease Dicer-2 (Dcr-2), whereas on the other hand an inducible response controlled by the evolutionarily conserved JAK/STAT pathway contributes to the antiviral host defence. In order to clarify the contribution of the siRNA and JAK/STAT pathways to the control of viral infections, we have compared the resistance of flies wild-type or mutant for Dcr-2 or the JAK kinase Hopscotch (Hop) to infections by seven RNA or DNA viruses belonging to different families. Our results reveal a unique susceptibility of hop mutant flies to infection by DCV and CrPV, two members of the Dicistroviridae family. Genome-wide microarray analysis confirmed that different sets of genes were induced following infection by DCV (GSE2828) or two unrelated RNA viruses, FHV and SINV. Overall, our data reveal that RNAi is an efficient antiviral mechanism, operating against a large range of viruses, including a DNA virus. By contrast, the antiviral contribution of the JAK/STAT pathway appears to be virus-specific. For each experimental challenge (FHV, 48 or 72 hours after infection; SINV, 4 or 8 days after infection), three biologically independent samples composed of 45 male Oregon R flies were used. Infection has been performed by injecting viral stocks prepared in Tris solution. Injection of the same volume of Tris has been used as control. Infected flies were then incubated for 48 or 72 hours in the case of FHV and 4 days or 8 days in the case of SINV.
