The Drosophila melanogaster sigma virus, a member of the Rhabdoviridae family, specifically propagates itself in D. melanogaster. It contains six genes in the order of 3'-N-P-X-M-G-L-5'. The sigma virus is the only arthropod-specific virus of the Rhabdoviridae family. Sigma-virus-infected Drosophila may suffer from irreversible paralysis when exposed to a high CO2 concentration, but generally, no other symptoms are reported. A recent study reported that host gene expression in immune pathways was not changed in sigma-virus-infected Drosophila, which does not necessarily suggest that they are not involved in virus-host interactions. The present study aimed to identify host genes associated with sigma virus replication. Immune pathways JAK-STAT and IMD were selected for detailed study. The results showed that the genome copy number of the sigma virus increased after knocking down the immune pathway genes domeless and PGRP-LC in Drosophila S2 cells. The knocking down of domeless and PGRP-LC significantly up-regulated the expression of the L gene compared to the other viral genes. We propose that the immune pathways respond to sigma virus infection by altering L expression, hence suppressing viral replication. This effect was further tested in vivo, when D. melanogaster individuals injected with dsdome and dsPGRP-LC showed not only an increase in sigma virus copy number, but also a reduced survival rate when treated with CO2. Our study proved that host immunity influences viral replication, even in persistent infection. Knocking down the key components of the immune process deactivates immune controls, thus facilitating viral expression and replication. We propose that the immunity system of D. melanogaster regulates the replication of the sigma virus by affecting the L gene expression. Studies have shown minimal host-virus interaction in persistent infection. However, our study demonstrated that the immunity continued to affect viral replication even in persistent infection because knocking down the key components of the immune process disabled the relevant immune controls and facilitated viral expression and replication.

Czech Academy of Sciences Biology Centre Institute of Entomology 37005 České Budějovice Czech Republic

Department of Entomology National Taiwan University Taipei 106 Taiwan

Faculty of Science University of South Bohemia 37005 České Budějovice Czech Republic

Zobrazit více v PubMed

Chtarbanova S., Lamiable O., Lee K.Z., Galiana D., Troxler L., Meignin C., Hetru C., Hoffmann J.A., Daeffler L., Imler J.L. Drosophila C Virus Systemic Infection Leads to Intestinal Obstruction. J. Virol. 2014;88:14057–14069. doi: 10.1128/JVI.02320-14. PubMed DOI PMC

Tsai C.W., McGraw E.A., Ammar E.D., Dietzgen R.G., Hogenhout S.A. Drosophila melanogaster mounts a unique immune response to the Rhabdovirus sigma virus. Appl. Environ. Microbiol. 2008;74:3251–3256. doi: 10.1128/AEM.02248-07. PubMed DOI PMC

Longdon B., Obbard D.J., Jiggins F.M. Sigma viruses from three species of Drosophila form a major new clade in the rhabdovirus phylogeny. Proc. R. Soc. B. 2010;277:35–44. doi: 10.1098/rspb.2009.1472. PubMed DOI PMC

Liang B., Li Z., Jenni S., Rahmeh A.A., Morin B.M., Grant T., Grigorieff N., Harrison S.C., Whelan S.P.J. Structure of the L Protein of Vesicular Stomatitis Virus from Electron Cryomicroscopy. Cell. 2015;162:314–327. doi: 10.1016/j.cell.2015.06.018. PubMed DOI PMC

Green T.J., Luo M. Structure of the vesicular stomatitis virus nucleocapsid in complex with the nucleocapsid-binding domain of the small polymerase cofactor, P. Proc. Natl. Acad. Sci. USA. 2009;106:11713–11718. doi: 10.1073/pnas.0903228106. PubMed DOI PMC

Fleuriet A. Evolution of the proportions of two sigma viral types in experimental populations of Drosophila melanogaster in the absence of the allele that is restrictive of viral multiplication. Genetics. 1999;153:1799–1808. PubMed PMC

Rosen L. Carbon dioxide sensitivity in mosquitoes infected with sigma, vesicular stomatitis, and other rhabdoviruses. Science. 1980;207:989–991. doi: 10.1126/science.6101512. PubMed DOI

Shroyer D.A., Rosen L. Extrachromosomal inheritance of carbon dioxide sensitivity in the mosquito Culex quinquefasciatus. Genetics. 1983;104:649–659. PubMed PMC

Carpenter J., Hutter S., Baines J.F., Roller J., Saminadin-Peter S.S., Parsch J., Jiggins F.M. The transcriptional response of Drosophila melanogaster to infection with the sigma virus (Rhabdoviridae) PLoS ONE. 2009;4:e6838. doi: 10.1371/journal.pone.0006838. PubMed DOI PMC

Fleuriet A., Sperlich D. Evolution of the Drosophila melanogaster-sigma virus system in a natural population from Tubingen. Theor. Appl. Genet. 1992;85:186–189. doi: 10.1007/BF00222858. PubMed DOI

Kingsolver M.B., Huang Z., Hardy R.W. Insect antiviral innate immunity: pathways, effectors, and connections. J. Mol. Biol. 2013;425:4921–4936. doi: 10.1016/j.jmb.2013.10.006. PubMed DOI PMC

Dostert C., Jouanguy E., Irving P., Troxler L., Galiana-Arnoux D., Hetru C., Hoffmann J.A., Imler J.L. The Jak-STAT signaling pathway is required but not sufficient for the antiviral response of drosophila. Nat. Immunol. 2005;6:946–953. doi: 10.1038/ni1237. PubMed DOI

Kaneko T., Goldman W.E., Mellroth P., Steiner H., Fukase K., Kusumoto S., Harley W., Fox A., Golenbock D., Silverman N. Monomeric and polymeric gram-negative peptidoglycan but not purified LPS stimulate the Drosophila IMD pathway. Immunity. 2004;20:637–649. doi: 10.1016/S1074-7613(04)00104-9. PubMed DOI

Mueller S., Gausson V., Vodovar N., Deddouche S., Troxler L., Perot J., Pfeffer S., Hoffmann J.A., Saleh M.C., Imler J.L. RNAi-mediated immunity provides strong protection against the negative-strand RNA vesicular stomatitis virus in Drosophila. Proc. Natl. Acad. Sci. USA. 2010;107:19390–19395. doi: 10.1073/pnas.1014378107. PubMed DOI PMC

Bronkhorst A.W., van Cleef K.W., Vodovar N., Ince I.A., Blanc H., Vlak J.M., Saleh M.C., van Rij R.P. The DNA virus Invertebrate iridescent virus 6 is a target of the Drosophila RNAi machinery. Proc. Natl. Acad. Sci. USA. 2012;109:E3604–E3613. doi: 10.1073/pnas.1207213109. PubMed DOI PMC

Sabin L.R., Zheng Q., Thekkat P., Yang J., Hannon G.J., Gregory B.D., Tudor M., Cherry S. Dicer-2 processes diverse viral RNA species. PLoS ONE. 2013;8:e55458. doi: 10.1371/journal.pone.0055458. PubMed DOI PMC

Gaines P.J., Olson K.E., Higgs S., Powers A.M., Beaty B.J., Blair C.D. Pathogen-derived resistance to dengue type 2 virus in mosquito cells by expression of the premembrane coding region of the viral genome. J. Virol. 1996;70:2132–2137. PubMed PMC

Zambon R.A., Nandakumar M., Vakharia V.N., Wu L.P. The Toll pathway is important for an antiviral response in Drosophila. Proc. Natl. Acad. Sci. USA. 2005;102:7257–7262. doi: 10.1073/pnas.0409181102. PubMed DOI PMC

Zambon R.A., Vakharia V.N., Wu L.P. RNAi is an antiviral immune response against a dsRNA virus in Drosophila melanogaster. Cell Microbiol. 2006;8:880–889. doi: 10.1111/j.1462-5822.2006.00688.x. PubMed DOI

Sabin L.R., Hanna S.L., Cherry S. Innate antiviral immunity in Drosophila. Curr. Opin. Immunol. 2010;22:4–9. doi: 10.1016/j.coi.2010.01.007. PubMed DOI PMC

Takeuchi O., Akira S. Pattern recognition receptors and inflammation. Cell. 2010;140:805–820. doi: 10.1016/j.cell.2010.01.022. PubMed DOI

Aliyari R., Wu Q., Li H.W., Wang X.H., Li F., Green L.D., Han C.S., Li W.X., Ding S.W. Mechanism of induction and suppression of antiviral immunity directed by virus-derived small RNAs in Drosophila. Cell Host Microbe. 2008;4:387–397. doi: 10.1016/j.chom.2008.09.001. PubMed DOI PMC

Belvin M.P., Anderson K.V. A conserved signaling pathway: the Drosophila toll-dorsal pathway. Annu. Rev. Cell Dev. Biol. 1996;12:393–416. doi: 10.1146/annurev.cellbio.12.1.393. PubMed DOI

Choe K.M., Lee H., Anderson K.V. Drosophila peptidoglycan recognition protein LC (PGRP-LC) acts as a signal-transducing innate immune receptor. Proc. Natl. Acad. Sci. USA. 2005;102:1122–1126. doi: 10.1073/pnas.0404952102. PubMed DOI PMC

Lee T., Luo L. Mosaic analysis with a repressible cell marker for studies of gene function in neuronal morphogenesis. Neuron. 1999;22:451–461. doi: 10.1016/S0896-6273(00)80701-1. PubMed DOI

Teninges D., Bras-Herreng F. Rhabdovirus sigma, the hereditary CO2 sensitivity agent of Drosophila: nucleotide sequence of a cDNA clone encoding the glycoprotein. Pt 10J. Gen. Virol. 1987;68:2625–2638. doi: 10.1099/0022-1317-68-10-2625. PubMed DOI

Longdon B., Hadfield J.D., Webster C.L., Obbard D.J., Jiggins F.M. Host phylogeny determines viral persistence and replication in novel hosts. PLoS Pathogens. 2011;7:e1002260. doi: 10.1371/journal.ppat.1002260. PubMed DOI PMC

Livak K.J., Schmittgen T.D. Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. Methods. 2001;25:402–408. doi: 10.1006/meth.2001.1262. PubMed DOI

Chen Y.W., Wu C.P., Wu T.C., Wu Y.L. Analyses of the transcriptome of Bombyx mori cells infected with either BmNPV or AcMNPV. J. Asia-Pac. Entomol. 2018;21:37–45. doi: 10.1016/j.aspen.2017.10.009. DOI

Dexter F. Wilcoxon-Mann-Whitney Test Used for Data That Are Not Normally Distributed. Anesth. Analg. 2013;117:537–538. doi: 10.1213/ANE.0b013e31829ed28f. PubMed DOI

Hu Y.T., Wu T.C., Yang E.C., Wu P.C., Lin P.T., Wu Y.L. Regulation of genes related to immune signaling and detoxification in Apis mellifera by an inhibitor of histone deacetylation. Sci. Rep-Uk. 2017;7 doi: 10.1038/srep41255. PubMed DOI PMC

Merkling S.H., van Rij R.P. Analysis of resistance and tolerance to virus infection in Drosophila. Nat. Protocols. 2015;10:1084–1097. doi: 10.1038/nprot.2015.071. PubMed DOI

Quadt I., Mainz D., Mans R., Kremer A., Knebel-Morsdorf D. Baculovirus infection raises the level of TATA-binding protein that colocalizes with viral DNA replication sites. J. Virol. 2002;76:11123–11127. doi: 10.1128/JVI.76.21.11123-11127.2002. PubMed DOI PMC

Kaneko T., Yano T., Aggarwal K., Lim J.H., Ueda K., Oshima Y., Peach C., Erturk-Hasdemir D., Goldman W.E., Oh B.H., et al. PGRP-LC and PGRP-LE have essential yet distinct functions in the drosophila immune response to monomeric DAP-type peptidoglycan. Nat. Immunol. 2006;7:715–723. doi: 10.1038/ni1356. PubMed DOI

Hsu S.F., Su W.C., Jeng K.S., Lai M.M. A host susceptibility gene, DR1, facilitates influenza A virus replication by suppressing host innate immunity and enhancing viral RNA replication. J. Virol. 2015;89:3671–3682. doi: 10.1128/JVI.03610-14. PubMed DOI PMC

Wang H.D., Trivedi A., Johnson D.L. Regulation of RNA polymerase I-dependent promoters by the hepatitis B virus X protein via activated Ras and TATA-binding protein. Mol. Cell. Biol. 1998;18:7086–7094. doi: 10.1128/MCB.18.12.7086. PubMed DOI PMC

Ward D.M., Vaughn M.B., Shiflett S.L., White P.L., Pollock A.L., Hill J., Schnegelberger R., Sundquist W.I., Kaplan J. The role of LIP5 and CHMP5 in multivesicular body formation and HIV-1 budding in mammalian cells. J. Biol. Chem. 2005;280:10548–10555. doi: 10.1074/jbc.M413734200. PubMed DOI