1
|
Cai H, Holleufer A, Simonsen B, Schneider J, Lemoine A, Gad HH, Huang J, Huang J, Chen D, Peng T, Marques JT, Hartmann R, Martins NE, Imler JL. 2'3'-cGAMP triggers a STING- and NF-κB-dependent broad antiviral response in Drosophila. Sci Signal 2020; 13:13/660/eabc4537. [PMID: 33262294 DOI: 10.1126/scisignal.abc4537] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We previously reported that an ortholog of STING regulates infection by picorna-like viruses in Drosophila In mammals, STING is activated by the cyclic dinucleotide 2'3'-cGAMP produced by cGAS, which acts as a receptor for cytosolic DNA. Here, we showed that injection of flies with 2'3'-cGAMP induced the expression of dSTING-regulated genes. Coinjection of 2'3'-cGAMP with a panel of RNA or DNA viruses resulted in substantially reduced viral replication. This 2'3'-cGAMP-mediated protection was still observed in flies with mutations in Atg7 and AGO2, genes that encode key components of the autophagy and small interfering RNA pathways, respectively. By contrast, this protection was abrogated in flies with mutations in the gene encoding the NF-κB transcription factor Relish. Transcriptomic analysis of 2'3'-cGAMP-injected flies revealed a complex response pattern in which genes were rapidly induced, induced after a delay, or induced in a sustained manner. Our results reveal that dSTING regulates an NF-κB-dependent antiviral program that predates the emergence of interferons in vertebrates.
Collapse
Affiliation(s)
- Hua Cai
- Sino-French Hoffmann Institute, State Key Laboratory of Respiratory Disease, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China.,Université de Strasbourg, CNRS UPR 9022, 67084 Strasbourg, France
| | - Andreas Holleufer
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Bine Simonsen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Aurélie Lemoine
- Université de Strasbourg, CNRS UPR 9022, 67084 Strasbourg, France
| | - Hans Henrik Gad
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Jingxian Huang
- Sino-French Hoffmann Institute, State Key Laboratory of Respiratory Disease, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China
| | - Jieqing Huang
- Sino-French Hoffmann Institute, State Key Laboratory of Respiratory Disease, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China
| | - Di Chen
- Sino-French Hoffmann Institute, State Key Laboratory of Respiratory Disease, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China
| | - Tao Peng
- Sino-French Hoffmann Institute, State Key Laboratory of Respiratory Disease, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China
| | - João T Marques
- Université de Strasbourg, CNRS UPR 9022, INSERM U1257, 67084 Strasbourg, France.,Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais CEP 31270901, Brazil
| | - Rune Hartmann
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark.
| | - Nelson E Martins
- Université de Strasbourg, CNRS UPR 9022, 67084 Strasbourg, France.
| | - Jean-Luc Imler
- Sino-French Hoffmann Institute, State Key Laboratory of Respiratory Disease, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China.,Université de Strasbourg, CNRS UPR 9022, 67084 Strasbourg, France
| |
Collapse
|
2
|
Drosophila immunity against natural and nonnatural viral pathogens. Virology 2019; 540:165-171. [PMID: 31928998 DOI: 10.1016/j.virol.2019.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/01/2019] [Indexed: 01/25/2023]
Abstract
The fruit fly Drosophila melanogaster is extensively used as a model species for molecular biology and genetics. It is also widely studied for its innate immune system to expand our understanding of immune host defenses against numerous pathogens. More precisely, studies using both natural and nonnatural Drosophila pathogens have provided a better perspective of viral infection strategies and immunity processes than any other invertebrate. This has made significant advances in identifying and characterizing the innate immune mechanisms by which hosts can combat viral pathogens. However, in-depth studies on antiviral immunity are still lacking due in part to the narrow research focus on the evolution and conservation of antiviral strategies to combat infections caused by both natural and nonnatural viruses. In this review, we will cover three major areas. First, we will describe the well-characterized antiviral immune mechanisms in Drosophila. Second, we will survey the specific pathways induced by natural viruses that have been studied in Drosophila. Finally, we will discuss the pathways activated by nonnatural viruses, drawing comparisons to natural viruses and giving an unprecedented insight into the virus community of Drosophila that is necessary to understand the evolutionary and immune context needed to develop Drosophila as a model for virus research.
Collapse
|
3
|
Duxbury EML, Day JP, Maria Vespasiani D, Thüringer Y, Tolosana I, Smith SCL, Tagliaferri L, Kamacioglu A, Lindsley I, Love L, Unckless RL, Jiggins FM, Longdon B. Host-pathogen coevolution increases genetic variation in susceptibility to infection. eLife 2019; 8:e46440. [PMID: 31038124 PMCID: PMC6491035 DOI: 10.7554/elife.46440] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 04/07/2019] [Indexed: 12/31/2022] Open
Abstract
It is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infection experiment involving four species of Drosophila and four host-specific viruses, we always found greater genetic variation in susceptibility to viruses that had coevolved with their host. We went on to examine the genetic architecture of resistance in one host species, finding that there are more major-effect genetic variants in coevolved host-pathogen interactions. We conclude that selection by pathogens has increased genetic variation in host susceptibility, and much of this effect is caused by the occurrence of major-effect resistance polymorphisms within populations.
Collapse
Affiliation(s)
- Elizabeth ML Duxbury
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
- School of Biological SciencesUniversity of East AngliaNorwichUnited Kingdom
| | - Jonathan P Day
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | | | - Yannik Thüringer
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Ignacio Tolosana
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Sophia CL Smith
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Lucia Tagliaferri
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Altug Kamacioglu
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Imogen Lindsley
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Luca Love
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Robert L Unckless
- Department of Molecular BiosciencesUniversity of KansasLawrenceUnited States
| | - Francis M Jiggins
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Ben Longdon
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
- Centre for Ecology and Conservation, BiosciencesUniversity of Exeter (Penryn Campus)CornwallUnited Kingdom
| |
Collapse
|
4
|
Parratt SR, Barrès B, Penczykowski RM, Laine AL. Local adaptation at higher trophic levels: contrasting hyperparasite-pathogen infection dynamics in the field and laboratory. Mol Ecol 2017; 26:1964-1979. [PMID: 27859910 PMCID: PMC5412677 DOI: 10.1111/mec.13928] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/25/2016] [Accepted: 11/01/2016] [Indexed: 12/23/2022]
Abstract
Predicting and controlling infectious disease epidemics is a major challenge facing the management of agriculture, human and wildlife health. Co-evolutionarily derived patterns of local adaptation among pathogen populations have the potential to generate variation in disease epidemiology; however, studies of local adaptation in disease systems have mostly focused on interactions between competing pathogens or pathogens and their hosts. In nature, parasites and pathogens are also subject to attack by hyperparasitic natural enemies that can severely impact upon their infection dynamics. However, few studies have investigated whether this interaction varies across combinations of pathogen-hyperparasite strains, and whether this influences hyperparasite incidence in natural pathogen populations. Here, we test whether the association between a hyperparasitic fungus, Ampelomyces, and a single powdery mildew host, Podosphaera plantaginis, varies among genotype combinations, and whether this drives hyperparasite incidence in nature. Laboratory inoculation studies reveal that genotype, genotype × genotype interactions and local adaptation affect hyperparasite infection. However, observations of a natural pathogen metapopulation reveal that spatial rather than genetic factors predict the risk of hyperparasite presence. Our results highlight how sensitive the outcome of biocontrol using hyperparasites is to selection of hyperparasite strains.
Collapse
Affiliation(s)
- Steven R Parratt
- Metapopulation Research Centre, Department of Biosciences, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
| | - Benoit Barrès
- Metapopulation Research Centre, Department of Biosciences, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
| | - Rachel M Penczykowski
- Metapopulation Research Centre, Department of Biosciences, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
| | - Anna-Liisa Laine
- Metapopulation Research Centre, Department of Biosciences, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
| |
Collapse
|
5
|
Webster CL, Waldron FM, Robertson S, Crowson D, Ferrari G, Quintana JF, Brouqui JM, Bayne EH, Longdon B, Buck AH, Lazzaro BP, Akorli J, Haddrill PR, Obbard DJ. The Discovery, Distribution, and Evolution of Viruses Associated with Drosophila melanogaster. PLoS Biol 2015; 13:e1002210. [PMID: 26172158 PMCID: PMC4501690 DOI: 10.1371/journal.pbio.1002210] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 06/26/2015] [Indexed: 11/18/2022] Open
Abstract
Drosophila melanogaster is a valuable invertebrate model for viral infection and antiviral immunity, and is a focus for studies of insect-virus coevolution. Here we use a metagenomic approach to identify more than 20 previously undetected RNA viruses and a DNA virus associated with wild D. melanogaster. These viruses not only include distant relatives of known insect pathogens but also novel groups of insect-infecting viruses. By sequencing virus-derived small RNAs, we show that the viruses represent active infections of Drosophila. We find that the RNA viruses differ in the number and properties of their small RNAs, and we detect both siRNAs and a novel miRNA from the DNA virus. Analysis of small RNAs also allows us to identify putative viral sequences that lack detectable sequence similarity to known viruses. By surveying >2,000 individually collected wild adult Drosophila we show that more than 30% of D. melanogaster carry a detectable virus, and more than 6% carry multiple viruses. However, despite a high prevalence of the Wolbachia endosymbiont--which is known to be protective against virus infections in Drosophila--we were unable to detect any relationship between the presence of Wolbachia and the presence of any virus. Using publicly available RNA-seq datasets, we show that the community of viruses in Drosophila laboratories is very different from that seen in the wild, but that some of the newly discovered viruses are nevertheless widespread in laboratory lines and are ubiquitous in cell culture. By sequencing viruses from individual wild-collected flies we show that some viruses are shared between D. melanogaster and D. simulans. Our results provide an essential evolutionary and ecological context for host-virus interaction in Drosophila, and the newly reported viral sequences will help develop D. melanogaster further as a model for molecular and evolutionary virus research.
Collapse
Affiliation(s)
- Claire L. Webster
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Fergal M. Waldron
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Shaun Robertson
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Daisy Crowson
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Giada Ferrari
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Juan F. Quintana
- Institute of Immunity and Infection Research, and the Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Jean-Michel Brouqui
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Elizabeth H. Bayne
- Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Ben Longdon
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Amy H. Buck
- Institute of Immunity and Infection Research, and the Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Brian P. Lazzaro
- Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Jewelna Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Penelope R. Haddrill
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Darren J. Obbard
- Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
6
|
Thézé J, Cabodevilla O, Palma L, Williams T, Caballero P, Herniou EA. Genomic diversity in European Spodoptera exigua multiple nucleopolyhedrovirus isolates. J Gen Virol 2014; 95:2297-2309. [PMID: 24854001 DOI: 10.1099/vir.0.064766-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Key virus traits such as virulence and transmission strategies rely on genetic variation that results in functional changes in the interactions between hosts and viruses. Here, comparative genomic analyses of seven isolates of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) with differing phenotypes were employed to pinpoint candidate genes that may be involved in host-virus interactions. These isolates obtained after vertical or horizontal transmission of infection in insects differed in virulence. Apart from one genome containing a piggyBac transposon, all European SeMNPV isolates had a similar genome size and content. Complete genome analyses of single nucleotide polymorphisms and insertions/deletions identified mutations in 48 ORFs that could result in functional changes. Among these, 13 ORFs could be correlated with particular phenotypic characteristics of SeMNPV isolates. Mutations were found in all gene functional classes and most of the changes we highlighted could potentially be associated with differences in transmission. The regulation of DNA replication (helicase, lef-7) and transcription (lef-9, p47) might be important for the establishment of sublethal infection prior to and following vertical transmission. Virus-host cell interactions also appear instrumental in the modulation of viral transmission as significant mutations were detected in virion proteins involved in primary (AC150) or secondary infections (ME35) and in apoptosis inhibition (IAP2, AC134). Baculovirus populations naturally harbour high genomic variation located in genes involved at different levels of the complex interactions between virus and host during the course of an infection. The comparative analyses performed here suggest that the differences in baculovirus virulence and transmission phenotypes involve multiple molecular pathways.
Collapse
Affiliation(s)
- Julien Thézé
- Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais de Tours, UFR Sciences et Techniques, 37200 Tours, France
| | - Oihana Cabodevilla
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
| | - Leopoldo Palma
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
| | | | - Primitivo Caballero
- Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Navarra, Spain.,Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
| | - Elisabeth A Herniou
- Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais de Tours, UFR Sciences et Techniques, 37200 Tours, France
| |
Collapse
|
7
|
Martins NE, Faria VG, Nolte V, Schlötterer C, Teixeira L, Sucena É, Magalhães S. Host adaptation to viruses relies on few genes with different cross-resistance properties. Proc Natl Acad Sci U S A 2014; 111:5938-43. [PMID: 24711428 PMCID: PMC4000853 DOI: 10.1073/pnas.1400378111] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Host adaptation to one parasite may affect its response to others. However, the genetics of these direct and correlated responses remains poorly studied. The overlap between these responses is instrumental for the understanding of host evolution in multiparasite environments. We determined the genetic and phenotypic changes underlying adaptation of Drosophila melanogaster to Drosophila C virus (DCV). Within 20 generations, flies selected with DCV showed increased survival after DCV infection, but also after cricket paralysis virus (CrPV) and flock house virus (FHV) infection. Whole-genome sequencing identified two regions of significant differentiation among treatments, from which candidate genes were functionally tested with RNAi. Three genes were validated--pastrel, a known DCV-response gene, and two other loci, Ubc-E2H and CG8492. Knockdown of Ubc-E2H and pastrel also led to increased sensitivity to CrPV, whereas knockdown of CG8492 increased susceptibility to FHV infection. Therefore, Drosophila adaptation to DCV relies on few major genes, each with different cross-resistance properties, conferring host resistance to several parasites.
Collapse
Affiliation(s)
| | - Vítor G. Faria
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Viola Nolte
- Institut für Populationsgenetik, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Christian Schlötterer
- Institut für Populationsgenetik, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
| | - Luis Teixeira
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
| | - Élio Sucena
- Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal
- Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal; and
| | - Sara Magalhães
- Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal; and
- Centro de Biologia Ambiental, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal
| |
Collapse
|
8
|
Wilfert L, Jiggins FM. Flies on the move: an inherited virus mirrors Drosophila melanogaster's elusive ecology and demography. Mol Ecol 2014; 23:2093-104. [PMID: 24597631 DOI: 10.1111/mec.12709] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 02/27/2014] [Accepted: 02/28/2014] [Indexed: 11/30/2022]
Abstract
Vertically transmitted parasites rely on their host's reproduction for their transmission, leading to the evolutionary histories of both parties being intimately entwined. Parasites can thus serve as a population genetic magnifying glass for their host's demographic history. Here, we study the fruitfly Drosophila melanogaster's vertically transmitted sigma virus DMelSV. The virus has a high mutation rate and low effective population size, allowing us to reconstruct at a fine scale how the combined forces of the movement of flies and selection on the virus have shaped its migration patterns. We found that the virus is likely to have spread to Europe from Africa, mirroring the colonization route of Drosophila. The North American DMelSV population appears to be the result of a recent single immigration from Europe, invading together with its host in the late 19th century. Across Europe, DMelSV migration rates are low and populations are highly genetically structured, likely reflecting limited fly movement. Despite being intolerant of extreme cold, viral diversity suggests that fly populations can persist in harsh continental climates and that recolonization from the warmer south plays a minor role. In conclusion, studying DMelSV can provide insights into the poorly understood ecology of D. melanogaster, one of the best-studied organisms in biology.
Collapse
Affiliation(s)
- Lena Wilfert
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, TR10 9FE, UK
| | | |
Collapse
|
9
|
Xu J, Cherry S. Viruses and antiviral immunity in Drosophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 42:67-84. [PMID: 23680639 PMCID: PMC3826445 DOI: 10.1016/j.dci.2013.05.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/26/2013] [Accepted: 05/02/2013] [Indexed: 05/10/2023]
Abstract
Viral pathogens present many challenges to organisms, driving the evolution of a myriad of antiviral strategies to combat infections. A wide variety of viruses infect invertebrates, including both natural pathogens that are insect-restricted, and viruses that are transmitted to vertebrates. Studies using the powerful tools in the model organism Drosophila have expanded our understanding of antiviral defenses against diverse viruses. In this review, we will cover three major areas. First, we will describe the tools used to study viruses in Drosophila. Second, we will survey the major viruses that have been studied in Drosophila. And lastly, we will discuss the well-characterized mechanisms that are active against these diverse pathogens, focusing on non-RNAi mediated antiviral mechanisms. Antiviral RNAi is discussed in another paper in this issue.
Collapse
Affiliation(s)
- Jie Xu
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | | |
Collapse
|
10
|
Hall MD, Ebert D. The genetics of infectious disease susceptibility: has the evidence for epistasis been overestimated? BMC Biol 2013; 11:79. [PMID: 23855805 PMCID: PMC3711976 DOI: 10.1186/1741-7007-11-79] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 07/08/2013] [Indexed: 12/30/2022] Open
Abstract
Interactions amongst genes, known as epistasis, are assumed to make a substantial contribution to the genetic variation in infectious disease susceptibility, but this claim is controversial. Here, we focus on the debate surrounding the evolutionary importance of interactions between resistance loci and argue that its role in explaining overall variance in disease outcomes may have been overestimated.
Collapse
Affiliation(s)
- Matthew D Hall
- University of Basel, Zoological Institute, Vesalgasse 1, Basel, CH-4051, Switzerland.
| | | |
Collapse
|
11
|
Wilfert L, Jiggins FM. The dynamics of reciprocal selective sweeps of host resistance and a parasite counter-adaptation in Drosophila. Evolution 2012; 67:761-73. [PMID: 23461326 DOI: 10.1111/j.1558-5646.2012.01832.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Host-parasite coevolution can result in consecutive selective sweeps of host resistance alleles and parasite counter-adaptations. To illustrate the dynamics of this important but little studied form of coevolution, we have modeled an ongoing arms race between Drosophila melanogaster and the vertically transmitted sigma virus, using parameters we estimated in the field. We integrate these results with previous work showing that the spread of a resistance allele of the ref(2)P gene in the host was followed by the spread of a virus genotype, which overcomes this resistance. In line with these observations, our model predicts that there can be rapid selective sweeps in both the host and parasite, which can drive large changes in the prevalence of infection. The virus will tend to be ahead in the arms race, as incomplete dominance slows down host adaptation and selection for host resistance is weaker than selection for parasites to overcome resistance--the "life-dinner" principle. This asymmetry in the adaptation rates results in a partial sweep of the host resistance allele, as it loses its advantage part way through the selective sweep. This well-understood natural system illustrates how the outcome of host-parasite coevolution is determined by different population genetic parameters in the field.
Collapse
Affiliation(s)
- Lena Wilfert
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom.
| | | |
Collapse
|
12
|
Longdon B, Jiggins FM. Vertically transmitted viral endosymbionts of insects: do sigma viruses walk alone? Proc Biol Sci 2012; 279:3889-98. [PMID: 22859592 PMCID: PMC3427579 DOI: 10.1098/rspb.2012.1208] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 07/06/2012] [Indexed: 01/10/2023] Open
Abstract
Insects are host to a wide range of vertically transmitted bacterial endosymbionts, but we know relatively little about their viral counterparts. Here, we discuss the vertically transmitted viral endosymbionts of insects, firstly examining the diversity of this group, and then focusing on the well-studied sigma viruses that infect dipterans. Despite limited sampling, evidence suggests that vertically transmitted viruses may be common in insects. Unlike bacteria, viruses can be transmitted through sperm and eggs, a trait that allows them to rapidly spread through host populations even when infection is costly to the host. Work on Drosophila melanogaster has shown that sigma viruses and their hosts are engaged in a coevolutionary arms race, in which the spread of resistance genes in the host population is followed by the spread of viral genotypes that can overcome host resistance. In the long-term, associations between sigma viruses and their hosts are unstable, and the viruses persist by occasionally switching to new host species. It therefore seems likely that viral endosymbionts have major impacts on the evolution and ecology of insects.
Collapse
Affiliation(s)
- Ben Longdon
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK.
| | | |
Collapse
|
13
|
Carpenter JA, Hadfield JD, Bangham J, Jiggins FM. Specific interactions between host and parasite genotypes do not act as a constraint on the evolution of antiviral resistance in Drosophila. Evolution 2011; 66:1114-25. [PMID: 22486692 DOI: 10.1111/j.1558-5646.2011.01501.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Genetic correlations between parasite resistance and other traits can act as an evolutionary constraint and prevent a population from evolving increased resistance. For example, previous studies have found negative genetic correlations between host resistance and life-history traits. In invertebrates, the level of resistance often depends on the combination of the host and parasite genotypes, and in this study, we have investigated whether such specific resistance also acts as an evolutionary constraint. We measured the resistance of different genotypes of the fruit fly Drosophila melanogaster to different genotypes of a naturally occurring pathogen, the sigma virus. Using a multitrait analysis, we examine whether genetic covariances alter the potential to select for general resistance against all of the different viral genotypes. We found large amounts of heritable variation in resistance, and evidence for specific interactions between host and parasite, but these interactions resulted in little constraint on Drosophila evolving greater resistance.
Collapse
Affiliation(s)
- Jennifer A Carpenter
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK.
| | | | | | | |
Collapse
|
14
|
Abstract
Insects are host to a diverse range of vertically transmitted micro-organisms, but while their bacterial symbionts are well-studied, little is known about their vertically transmitted viruses. We have found that two sigma viruses (Rhabdoviridae) recently discovered in Drosophila affinis and Drosophila obscura are both vertically transmitted. As is the case for the sigma virus of Drosophila melanogaster, we find that both males and females can transmit these viruses to their offspring. Males transmit lower viral titers through sperm than females transmit through eggs, and a lower proportion of their offspring become infected. In natural populations of D. obscura in the United Kingdom, we found that 39% of flies were infected and that the viral population shows clear evidence of a recent expansion, with extremely low genetic diversity and a large excess of rare polymorphisms. Using sequence data we estimate that the virus has swept across the United Kingdom within the past ∼11 years, during which time the viral population size doubled approximately every 9 months. Using simulations based on our lab estimates of transmission rates, we show that the biparental mode of transmission allows the virus to invade and rapidly spread through populations at rates consistent with those measured in the field. Therefore, as predicted by our simulations, the virus has undergone an extremely rapid and recent increase in population size. In light of this and earlier studies of a related virus in D. melanogaster, we conclude that vertically transmitted rhabdoviruses may be common in insects and that these host-parasite interactions can be highly dynamic.
Collapse
|
15
|
Wayne ML, Blohm GM, Brooks ME, Regan KL, Brown BY, Barfield M, Holt RD, Bolker BM. The prevalence and persistence of sigma virus, a biparentally transmitted parasite of Drosophila melanogaster. EVOLUTIONARY ECOLOGY RESEARCH 2011; 13:323-345. [PMID: 28217032 PMCID: PMC5313041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
QUESTION How do vertically transmitted parasites persist? ORGANISMS Drosophila melanogaster (host) and sigma virus (parasite). FIELD SITE Peach stands in northern Georgia, USA, on a transect between Macon and Athens. EMPIRICAL METHODS We estimated prevalence in the field. We also estimated male and female transmission in the laboratory, using field-collected animals as parents. We further quantified patrilineal (father to son) transmission in the laboratory, and estimated cost of infection (virulence) by quantifying decreased egg production of infected flies. MATHEMATICAL METHODS Discrete-time, deterministic models for prevalence; analysis of stability of disease-free and endemic equilibria; numerical computation of equilibria based on empirical estimates. KEY ASSUMPTIONS Random mating, discrete generations, cost of infection to females only. PREDICTIONS AND CONCLUSIONS The model allows persistence under parameter estimates obtained for this population. Uncertainty in parameters leads to wide confidence intervals on the predicted prevalence, which may be systematically underestimated due to Jensen's inequality. Male transmission is required for persistence, and multiple generations of strictly patrilineal transmission are possible in the laboratory, albeit with decreasing transmission efficiency.
Collapse
Affiliation(s)
- Marta L Wayne
- Department of Biology, University of Florida, Gainesville, Florida, USA ; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA ; UF Genetics Institute, University of Florida, Gainesville, Florida, USA
| | - Gabriela M Blohm
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Mollie E Brooks
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Kerry L Regan
- Department of Biology, University of Florida, Gainesville, Florida, USA ; Department of Biological Sciences, University of Notre Dame, South Bend, Indiana, USA
| | - Brennin Y Brown
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Michael Barfield
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Robert D Holt
- Department of Biology, University of Florida, Gainesville, Florida, USA ; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| | - Benjamin M Bolker
- Department of Biology, University of Florida, Gainesville, Florida, USA ; Department of Mathematics, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
16
|
Yamauchi A, Telschow A, Kobayashi Y. Evolution of cytoplasmic sex ratio distorters: Effect of paternal transmission. J Theor Biol 2010; 266:79-87. [PMID: 20558180 DOI: 10.1016/j.jtbi.2010.06.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 06/09/2010] [Accepted: 06/09/2010] [Indexed: 11/27/2022]
Abstract
Eukaryotic organisms carry various genetic factors the so-called cytoplasmic genetic elements (CGEs), in their cytoplasm. Numerous examples are known in which CGEs possess the ability to control sex determination of their host organisms and cause sex ratio distortion (SRD). In general, CGEs are inherited maternally from female hosts, via egg cytoplasm to offspring. Thus, the elements tend to evolve abilities to avoid entrance into "dead-end" males. Previous theoretical studies have revealed that, as long as maternal transmission is perfect, CGEs evolve the highest levels of ability to cause SRD. However, it is recently reported that some CGEs transmit from male to offspring through infection to female in mating. This raises the question of how such a paternal contribution alters selective forces and SRD evolution. In the present study, the evolutionary process of SRD ability of CGEs was analyzed theoretically. The main finding is that paternal transmission results in evolution towards intermediate levels of SRD. Further, coexistence was observed of different CGEs inducing different levels of SRD. These results point to the importance of paternal transmission in the evolution of CGEs.
Collapse
Affiliation(s)
- Atsushi Yamauchi
- Center for Ecological Research, Kyoto University, Hirano 2-509-3, Otsu 520-2113, Japan.
| | | | | |
Collapse
|
17
|
Wang JH, Valanne S, Rämet M. Drosophila as a model for antiviral immunity. World J Biol Chem 2010; 1:151-9. [PMID: 21541000 PMCID: PMC3083956 DOI: 10.4331/wjbc.v1.i5.151] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 05/04/2010] [Accepted: 05/17/2010] [Indexed: 02/05/2023] Open
Abstract
The fruit fly Drosophila melanogaster has been successfully used to study numerous biological processes including immune response. Flies are naturally infected with more than twenty RNA viruses making it a valid model organism to study host-pathogen interactions during viral infections. The Drosophila antiviral immunity includes RNA interference, activation of the JAK/STAT and other signaling cascades and other mechanisms such as autophagy and interactions with other microorganisms. Here we review Drosophila as an immunological research model as well as recent advances in the field of Drosophila antiviral immunity.
Collapse
Affiliation(s)
- Jing-Huan Wang
- Jing-Huan Wang, Susanna Valanne, Mika Rämet, Institute of Medical Technology, University of Tampere, 33520 Tampere, Finland
| | | | | |
Collapse
|
18
|
Wilfert L, Jiggins FM. Host-parasite coevolution: genetic variation in a virus population and the interaction with a host gene. J Evol Biol 2010; 23:1447-55. [PMID: 20456575 DOI: 10.1111/j.1420-9101.2010.02002.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Host-parasite coevolution is considered to be an important factor in maintaining genetic variation in resistance to pathogens. Drosophila melanogaster is naturally infected by the sigma virus, a vertically transmitted and host-specific pathogen. In fly populations, there is a large amount of genetic variation in the transmission rate from parent to offspring, much of which is caused by major-effect resistance polymorphisms. We have found that there are similarly high levels of genetic variation in the rate of paternal transmission among 95 different isolates of the virus as in the host. However, when we examined a transmission-blocking gene in the host, we found that it was effective across virus isolates. Therefore, the high levels of genetic variation observed in this system do not appear to be maintained because of coevolution resulting from interactions between this host gene and parasite genes.
Collapse
Affiliation(s)
- L Wilfert
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK.
| | | |
Collapse
|
19
|
Abstract
Association and linkage mapping have become important tools in understanding the genetics of complex traits, including diseases in humans. As the success of association mapping is reduced by small effect sizes and limited power, linkage studies in laboratory-based model systems are still heavily used. But whether the results of these studies can be replicated in natural populations has been questioned. Here, we show that a polymorphism in the gene ref(2)P, which had previously been linked to sigma virus resistance in Drosophila melanogaster under laboratory conditions, also provides resistance against the virus in female flies in a wild population in the field. This genetic association is thus upheld in spite of a known genotype-by-genotype interaction and environmental variation.
Collapse
Affiliation(s)
- Lena Wilfert
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK.
| | | |
Collapse
|
20
|
Varaldi J, Patot S, Nardin M, Gandon S. A virus-shaping reproductive strategy in a Drosophila parasitoid. ADVANCES IN PARASITOLOGY 2009; 70:333-63. [PMID: 19773077 DOI: 10.1016/s0065-308x(09)70013-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Insect parasitoids are often infected with heritable viruses. Some of them, such as polydnaviruses, have evolved toward an obligatory relationship with the parasitoid because they are necessary to protect the parasitoid egg from the host immune reaction. However, recent and past discoveries have revealed the presence of facultative inherited viruses in parasitoids for which no clear phenotypic effect was observed. In this chapter, we present how such an inherited virus was recently discovered in the Drosophila parasitoid, Leptopilina boulardi. We show that this virus is responsible for an increase in the superparasitism tendency of the infected females. This alteration is beneficial for the virus, since superparasitism conditions permit the horizontal transmission of the virus. We review theoretical developments suggesting that this leads to a conflict of interest between the parasitoid and the virus. The direct and indirect influence of the virus on several other fitness traits has also been studied both empirically and theoretically, in particular the egg load. Finally, because the frequency of horizontal transmission is a crucial parameter for the evolution of the superparasitism manipulation, we present an attempt to select the virus for high or low manipulation intensity.
Collapse
Affiliation(s)
- Julien Varaldi
- Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1, CNRS, UMR 5558, F-69622 Villeurbanne, France
| | | | | | | |
Collapse
|
21
|
Costa A, Jan E, Sarnow P, Schneider D. The Imd pathway is involved in antiviral immune responses in Drosophila. PLoS One 2009; 4:e7436. [PMID: 19829691 PMCID: PMC2758544 DOI: 10.1371/journal.pone.0007436] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Accepted: 08/13/2009] [Indexed: 12/15/2022] Open
Abstract
Cricket Paralysis virus (CrPV) is a member of the Dicistroviridae family of RNA viruses, which infect a broad range of insect hosts, including the fruit fly Drosophila melanogaster. Drosophila has emerged as an effective system for studying innate immunity because of its powerful genetic techniques and the high degree of gene and pathway conservation. Intra-abdominal injection of CrPV into adult flies causes a lethal infection that provides a robust assay for the identification of mutants with altered sensitivity to viral infection. To gain insight into the interactions between viruses and the innate immune system, we injected wild type flies with CrPV and observed that antimicrobial peptides (AMPs) were not induced and hemocytes were depleted in the course of infection. To investigate the contribution of conserved immune signaling pathways to antiviral innate immune responses, CrPV was injected into isogenic mutants of the Immune Deficiency (Imd) pathway, which resembles the mammalian Tumor Necrosis Factor Receptor (TNFR) pathway. Loss-of-function mutations in several Imd pathway genes displayed increased sensitivity to CrPV infection and higher CrPV loads. Our data show that antiviral innate immune responses in flies infected with CrPV depend upon hemocytes and signaling through the Imd pathway.
Collapse
Affiliation(s)
- Alexandre Costa
- Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America
| | - Eric Jan
- Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America
| | - Peter Sarnow
- Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America
| | - David Schneider
- Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America
- * E-mail:
| |
Collapse
|
22
|
Carpenter J, Hutter S, Baines JF, Roller J, Saminadin-Peter SS, Parsch J, Jiggins FM. The transcriptional response of Drosophila melanogaster to infection with the sigma virus (Rhabdoviridae). PLoS One 2009; 4:e6838. [PMID: 19718442 PMCID: PMC2730013 DOI: 10.1371/journal.pone.0006838] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 08/06/2009] [Indexed: 11/18/2022] Open
Abstract
Background Bacterial and fungal infections induce a potent immune response in Drosophila melanogaster, but it is unclear whether viral infections induce an antiviral immune response. Using microarrays, we examined the changes in gene expression in Drosophila that occur in response to infection with the sigma virus, a negative-stranded RNA virus (Rhabdoviridae) that occurs in wild populations of D. melanogaster. Principal Findings We detected many changes in gene expression in infected flies, but found no evidence for the activation of the Toll, IMD or Jak-STAT pathways, which control immune responses against bacteria and fungi. We identified a number of functional categories of genes, including serine proteases, ribosomal proteins and chorion proteins that were overrepresented among the differentially expressed genes. We also found that the sigma virus alters the expression of many more genes in males than in females. Conclusions These data suggest that either Drosophila do not mount an immune response against the sigma virus, or that the immune response is not controlled by known immune pathways. If the latter is true, the genes that we identified as differentially expressed after infection are promising candidates for controlling the host's response to the sigma virus.
Collapse
Affiliation(s)
- Jennifer Carpenter
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
23
|
Schulenburg H, Kurtz J, Moret Y, Siva-Jothy MT. Introduction. Ecological immunology. Philos Trans R Soc Lond B Biol Sci 2009; 364:3-14. [PMID: 18926970 DOI: 10.1098/rstb.2008.0249] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An organism's fitness is critically reliant on its immune system to provide protection against parasites and pathogens. The structure of even simple immune systems is surprisingly complex and clearly will have been moulded by the organism's ecology. The aim of this review and the theme issue is to examine the role of different ecological factors on the evolution of immunity. Here, we will provide a general framework of the field by contextualizing the main ecological factors, including interactions with parasites, other types of biotic as well as abiotic interactions, intraspecific selective constraints (life-history trade-offs, sexual selection) and population genetic processes. We then elaborate the resulting immunological consequences such as the diversity of defence mechanisms (e.g. avoidance behaviour, resistance, tolerance), redundancy and protection against immunopathology, life-history integration of the immune response and shared immunity within a community (e.g. social immunity and microbiota-mediated protection). Our review summarizes the concepts of current importance and directs the reader to promising future research avenues that will deepen our understanding of the defence against parasites and pathogens.
Collapse
Affiliation(s)
- Hinrich Schulenburg
- Zoological Institute, University of Kiel, Am Botanischen Garten, 24098 Kiel, Germany.
| | | | | | | |
Collapse
|
24
|
Bangham J, Knott SA, Kim KW, Young RS, Jiggins FM. Genetic variation affecting host-parasite interactions: major-effect quantitative trait loci affect the transmission of sigma virus in Drosophila melanogaster. Mol Ecol 2008; 17:3800-7. [PMID: 18665899 DOI: 10.1111/j.1365-294x.2008.03873.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In natural populations, genetic variation affects resistance to disease. Whether that genetic variation comprises lots of small-effect polymorphisms or a small number of large-effect polymorphisms has implications for adaptation, selection and how genetic variation is maintained in populations. Furthermore, how much genetic variation there is, and the genes that underlie this variation, affects models of co-evolution between parasites and their hosts. We are studying the genetic variation that affects the resistance of Drosophila melanogaster to its natural pathogen--the vertically transmitted sigma virus. We have carried out three separate quantitative trait locus mapping analyses to map gene variants on the second chromosome that cause variation in the rate at which males transmit the infection to their offspring. All three crosses identified a locus in a similar chromosomal location that causes a large drop in the rate at which the virus is transmitted. We also found evidence for an additional smaller-effect quantitative trait locus elsewhere on the chromosome. Our data, together with previous experiments on the sigma virus and parasitoid wasps, indicate that the resistance of D. melanogaster to co-evolved pathogens is controlled by a limited number of major-effect polymorphisms.
Collapse
Affiliation(s)
- Jenny Bangham
- School of Biological Sciences, Institute of Evolutionary Biology, The University of Edinburgh, Ashworth Laboratories, The King's Buildings, West Mains Road, Edinburgh, UK.
| | | | | | | | | |
Collapse
|