Description
The response of drosophila to bacterial and fungal infections involves two signaling pathways, Toll and Imd, which both activate NF-kB family members. We have studied the global transcriptional response of flies to infection with drosophila C virus. Viral infection induced a set of genes distinct from those regulated by the Toll or Imd pathways, and triggered activation of a STAT binding activity. Genetic experiments showed that the JAK kinase Hopscotch was involved in the control of the viral load in infected flies, and was required, though not sufficient, for the induction of some virus-regulated genes. Our results indicate that in addition to Toll and Imd, a third evolutionary conserved innate immunity pathway operates in drosophila and counters viral infection.