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.
The Jak-STAT signaling pathway is required but not sufficient for the antiviral response of drosophila.
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View SamplesKATP opposes depolarization of cells in the heart, smooth muscle, and other tissues by permitting the efflux of potassium ions and this efflux is evidently required to prevent unopposed vasoconstriction and insufficiency of coronary artery blood flow triggered by one or more cytokines induced in response to LPS. The cytokine(s) involved must elicit a dysfunctional response in the Kir6.1-deficient environment, and to gain further insight into the effects of the mutation, we examined the transcriptional status of whole heart, isolated from normal C57BL/6J mice or KcnJ8Md/Md mice, before and after injection of 1 g of LPS
ATP-sensitive potassium channels mediate survival during infection in mammals and insects.
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View SamplesThe 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.
Broad RNA interference-mediated antiviral immunity and virus-specific inducible responses in Drosophila.
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