Comparative microarray analysis of psh and Dif mutant flies treated with Metarhizium anisopliae ARSEF 549
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ABSTRACT: The Toll pathway is the chief antifungal pathway in Drosophila. Two components of this pathway have disparate effects on Drosophila infected with Metarhizium ansiopliae ARSEF 549 (Ma549). Infected Drosophila Dif mutants show no change in susceptibility while infected psh mutants rapidly succumb to infection. We evaluated the impact of Ma549 on gene regulation in flies deficient in these Toll pathway components to identify the cause for these susceptibility differences. Four fly lines were used: psh, BDSC6326 (psh control), Dif, and cn bw (Dif control). RNA was collected 46 hrs post infection for 10 infected or uninfected male flies per replicate.
Project description:LncRNAs have important regulatory functions but their roles in Drosophila innate immunity are poorly understood. The Drosophila Toll signaling pathway responds to Gram-positive bacterial infection and is highly conserved with mammalian TLR signaling. Recent studies focused mainly on Toll signaling pathway regulation by protein-coding genes. In the present study, we found that lncRNA-CR33942 was upregulated after Micrococcus luteus infection. Gain-of-function and loss-of-function assays disclosed that lncRNA-CR33942 regulates the Toll signaling pathway and affects Drosophila survival. RNA-seq of infected CR33942-overexpressing flies was performed to explore the CR33942 mechanism. About 70% of all upregulated core enrichment genes in the Toll signaling pathway were antibacterial peptides and PGRPs transcribed by Dif/Dorsal. We also demonstrated CR33942 interactions with Dif/Dorsal and revealed that they induce antibacterial peptides. Hence, we renamed CR33942 as lncRNA-NANPI (NF-κB-associated non-coding RNA promotional immunology). The present study identified the novel Toll signaling pathway regulator NANPI, elucidated its mode of action, clarified the function of lncRNA, and expanded our understanding of the Toll signaling pathway.
Project 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.
Project description:The Toll signaling pathway is highly conserved from insects to mammals. Drosophila is a model species that is commonly used to study innate immunity. Although many studies have assessed protein-coding genes that regulate the Toll pathway, it is unclear whether long noncoding RNAs (lncRNAs) play regulatory roles in the Toll pathway. Here, we evaluated the expression of the lncRNA CR46018 in Drosophila. Our results showed that this lncRNA was significantly overexpressed after infection of Drosophila with Micrococcus luteus. A CR46018-overexpressing Drosophila strain was then constructed; we expected that CR46018 overexpression would enhance the expression of various antimicrobial peptides downstream of the Toll pathway, regardless of infection with M. luteus. RNA-seq analysis of CR46018-overexpressing Drosophila after infection with M. luteus showed that upregulated genes were mainly enriched in Toll and Imd signaling pathways. Moreover, bioinformatics predictions and RNA-immunoprecipitation experiments showed that CR46018 interacted with the transcription factors Dif and Dorsal to enhance the Toll pathway. During gram-positive bacterial infection, flies overexpressing CR46018 showed favorable survival compared with flies in the control group. Based on these findings, we renamed CR46018 as lncRNA-RDIP. Overall, our current work not only reveals a new immune regulatory factor, lncRNA-RDIP, and explores its potential regulatory model, but also provides a new perspective for the effect of immune disorders on the survival of Drosophila melanogaster.
Project description:Combination of both sterile wounding and infection may lead to severe health defects, revealing the importance of the balance between the intensity and resolution of the inflammatory response for the organisms fitness. Underlying mechanisms remain however elusive. Using Drosophila, we analyzed the very first steps of the process by comparing the transcriptome landscape of infected (simple hit flies, SH), wounded and infected (double hit flies, DH) and wounded (control) flies. Our objective was to identify the molecular mechanisms underlying the susceptibility of wounded flies to combined trauma and bacterial infection.
Project description:To combat infection, an immune system needs to be promptly activated but tightly controlled to avoid destructive effects on host tissues. IbinA and IbinB are related short peptides with robust expression upon microbial challenge in Drosophila melanogaster. Here, we show that Ibin genes are ubiquitously present in flies of the Drosophila subgenus Sophophora, where they replace a different but probably related gene, Mibin, which is found across a much wider range of cyclorrhaphan flies. Using synthetic peptides, we did not observe any direct bactericidal or bacteriostatic activity for either IbinA or IbinB in vitro. Using mutant Drosophila lines lacking the IbinA gene, IbinB gene, or both, we examined their roles in development and during microbial infections. IbinA is expressed in early pupae, and a lack of IbinA and IbinB leads to temperature-dependent formation of melanized tissue during metamorphosis, frequently around the trachea. IbinA and IbinB have distinct effects on susceptibility to microbial infection. For example, IbinB mutant flies, as well as flies lacking both IbinA and IbinB, had improved survival when challenged with Listeria monocytogenes, an intracellular pathogen, whereas a lack of IbinA alone had no effect. RNA sequencing of wildtype and mutant flies infected with L. monocytogenes showed enhanced Toll target gene expression in flies lacking IbinB, suggesting that IbinB acts as a negative regulator of the Toll pathway. In contrast, IbinA mutants had decreased Toll target gene expression in this context. Correspondingly, IbinB mutant flies had improved and IbinA compromised survival in septic fungal infection, where the Toll pathway has a major role. Our study provides insight into the roles of IbinA and IbinB in regulation of the immune response in Drosophila.
Project description:The maintenance of innate immune homeostasis is critical for animal survival to combat pathogens. Although many positive or negative protein factors have been identified, little is known about the long non-coding RNA that regulates the Toll pathway. Herein, we have discovered a novel lncRNA-CR11538 highly activated during the Drosophila response to gram+ bacterial infection. The transient overexpression of CR11538 inhibited the expression of antimicrobial peptides (Drosomycin and Metchnikowin) in vivo to suppress Toll signaling pathway. Remarkably, core enrichment genes based on RNAseq, subcellular localization and RIP suggest that CR11538 can interact with the transcription factor Dif/Dorsal in nucleus. ChIP-qPCR and dual luciferase report experiments show that CR11538 can sequester Dif/Dorsal away from the promoter thus suppressing the transcription of antimicrobial peptides. In summary, we discovered a novel lncRNA-CR11538 that negatively regulate the Drosophila Toll pathway. It broadens our understanding of the regulatory mechanism of Toll pathway involving lncRNA and provides insights for the research on innate immune system of insects and mammals.
Project 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. Keywords: JAK/STAT virus drosophila immunity
Project description:Tsetse flies (Glossina spp.) are major vectors of African trypanosomes, causing either Human or Animal African Trypanosomiasis (HAT or AAT). Several approaches are developed to control the disease among which the anti-vector Sterile Insect Technique. Another approach in the frame of anti-vector strategies could consist in controlling the fly’s vector competence which needs identifying factors (genes, proteins, biological pathways, …) involved in this process. The present work aims to verify whether protein candidates identified under experimental controlled conditions on insectary-reared tsetse flies have their counterpart in field-collected flies. Glossina palpalis palpalis flies naturally infected with Trypanosoma congolense were sampled in two HAT/AAT foci in Southern Cameroon. After dissection, the proteome from guts of parasite-infected flies were compared to that from uninfected flies in order to identify quantitative and/or qualitative changes associated to infection. A total of 3291 proteins were identified of which 1818 could be quantified. The comparative analysis allowed identifying 175 proteins with significant decreased abundance in infected as compared to uninfected flies, while 61 proteins displayed increased abundance. Among the former are RNA binding proteins, kinases, actin, ribosomal proteins, endocytosis proteins, oxido-reductases, as well as proteins that are unusually found such as tsetse salivary proteins (Tsal) or Yolk proteins. Among the proteins with increased abundance are fructose-1,6-biphosphatase, serine proteases, membrane trafficking proteins, death proteins (or apoptosis proteins), and SERPINs (inhibitor of serine proteases, enzymes considered as trypanosome virulence factors) that displayed highest increased abundance. Sodalis, Wiggleswothia and Wolbachia proteins are strongly under-represented, particularly when compared to data from similar experimentation conducted under controlled conditions on T. brucei gambiense infected (or uninfected) G. palpalis gambiensis insectary reared flies. Comparing the overall recorded data, 364 proteins identified in gut extracts from field flies were shown to have a homologue in insectary flies. Discrepancies between the two studies may arise from differences in the species of studied flies and trypanosomes as well as in differences in environmental conditions in which the two experiments were carried out. Finally, the present study together with former proteomic and transcriptomic studies on the secretome of trypanosomes, on the gut extracts from insectary reared and on field collected tsetse flies, provide a pool of data and information on which to draw in order to perform further investigations on, for example, mammal host immunization or on fly vector competence modification via para-transgenic approaches.
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.
Project description:Wild-type Drosophila melanogaster expressing nuclear GFP-KASH fusion protein in photoreceptors for cell type-specific gene expression profiling (Rh1-Gal4>UAS-GFPKASH ; Genotype = w1118;; P{w+mC=[UAS-GFP-Msp300KASH}attP2, P{ry+t7.2=rh1-GAL4}3, ry506) were raised in 12:12h light:dark cycle at 25°C. Flies were aged for 10 or 40 days post-eclosion, and eyes were harvested from male flies for global quantitative proteomic analysis. Significantly changed proteins were identified that may contribute to age-associated retinal degeneration and loss of visual function in the aging Drosophila eye.