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Abstract
Microbial symbioses exhibit astounding adaptations, yet all symbionts face the problem of how to reliably associate with host offspring every generation. A common strategy is vertical transmission, in which symbionts are directly transmitted from the female to her offspring. The diversity of symbionts and vertical transmission mechanisms is as expansive as the diversity of eukaryotic host taxa that house them. However, there are several common themes among these mechanisms based on the degree to which symbionts associate with the host germline during transmission. In this review, we detail three distinct vertical transmission strategies, starting with associations that are transmitted from host somatic cells to offspring somatic cells, either due to lacking a germline or avoiding it. A second strategy involves somatically-localized symbionts that migrate into the germline during host development. The third strategy we discuss is one in which the symbiont maintains continuous association with the germline throughout development. Unexpectedly, the vast majority of documented vertically inherited symbionts rely on the second strategy: soma-to-germline migration. Given that not all eukaryotes contain a sequestered germline and instead produce offspring from somatic stem cell lineages, this soma-to-germline migration is discussed in the context of multicellular evolution. Lastly, as recent genomics data have revealed an abundance of horizontal gene transfer events from symbiotic and non-symbiotic bacteria to host genomes, we discuss their impact on eukaryotic host evolution.
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Affiliation(s)
- Shelbi L Russell
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, United States.
| | - Laura Chappell
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, United States
| | - William Sullivan
- Department of Molecular, Cell, and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, United States
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52
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Abstract
The Wolbachia endosymbionts encompass a large group of intracellular bacteria of biomedical and veterinary relevance, closely related to Anaplasma, Ehrlichia, and Rickettsia. This genus of Gram-negative members of the Alphaproteobacteria does not infect vertebrates but is instead restricted to ecdysozoan species, including terrestrial arthropods and a family of parasitic filarial nematodes, the Onchocercidae. The Wolbachia profoundly impact not only the ecology and evolution but also the reproductive biology of their hosts, through a wide range of symbiotic interactions. Because they are essential to the survival and reproduction of their filarial nematode hosts, they represent an attractive target to fight filariasis. Their abilities to spread through insect populations and to affect vector competence through pathogen protection have made Wolbachia a staple for controlling vector-borne diseases. Estimated to be present in up to 66% of insect species, the Wolbachia are probably the most abundant endosymbionts on earth. Their success resides in their unique capacity to infect and manipulate the host germ line to favor their vertical transmission through the maternal lineage. Because the Wolbachia resist genetic manipulation and growth in axenic culture, our understanding of their biology is still in its infancy. Despite these limitations, the "-omics" revolution combined with the use of well-established and emerging experimental host models is accelerating our comprehension of the host phenotypes caused by Wolbachia, and the identification of Wolbachia effectors is ongoing.
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53
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Mating barriers between genetically divergent strains of the parasitic nematode Haemonchus contortus suggest incipient speciation. Int J Parasitol 2019; 49:531-540. [PMID: 31034791 DOI: 10.1016/j.ijpara.2019.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/25/2019] [Accepted: 02/03/2019] [Indexed: 11/21/2022]
Abstract
Haemonchus contortus, in common with many nematode species, has extremely high levels of genetic variation within and between field populations derived from distant geographical locations. MHco10(CAVR), MHco3(ISE) and MHco4(WRS) are genetically divergent H. contortus strains, originally derived from Australia, Kenya and South Africa, respectively, that have been maintained by numerous rounds of in vivo experimental infection of sheep. In order to explore potential pre-zygotic competition or post-zygotic incompatibility between the strains, we have investigated the ability of MHco10(CAVR) to interbreed with either MHco3(ISE) or MHco4(WRS) during dual strain co-infections. Sheep were experimentally co-infected with 4000 infective larvae (L3) per os of the MHco10(CAVR) strain and an equal number of either the MHco3(ISE) or the MHco4(WRS) strain L3. The adult worm establishement rates and the proportions of F1 progeny resulting from intra- and inter-strain mating events were determined by admixture analysis of microsatellite multi-locus genotypes. Although there was no difference in adult worm establishment rates, the proportions of F1 progeny of both the MHco10(CAVR) × MHco3(ISE) and MHco10(CAVR) × MHco4(WRS) dual strain co-infections departed from Mendelian expectations. The proportions of inter-strain hybrid F1 progeny were lower than the expected 50%, suggesting either pre-zygotic competition or post-zygotic incompatibility between the co-infecting strains. To investigate this further, both eggs and hatched L1 of broods from single adult female worms recovered from each dual co-infection were genotyped. Unhatched eggs from the broods revealed no inter-strain hybrid genotype deficit, suggesting there is no pre-zygotic competition between the strains. In contrast, there was a deficit in L1 inter-strain hybrid genotypes in the broods derived from MHco3(ISE) or MHco4(WRS) maternal parents, but not from MHco10(CAVR) maternal parents. This suggests that hybrid progeny of MHco10(CAVR) paternal parents have reduced post-zygotic development and/or viability consistent with incipient speciation of the MHco10(CAVR) strain. The presence of mating barriers between allopatric H. contortus strains has important implications for parasite ecology, including the ability of newly introduced anthelmintic-resistant parasite populations to compete and interbreed with populations already established in a region.
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Bi J, Zheng Y, Wang RF, Ai H, Haynes PR, Brownlie JC, Yu XQ, Wang YF. Wolbachia infection may improve learning and memory capacity of Drosophila by altering host gene expression through microRNA. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 106:47-54. [PMID: 30468769 DOI: 10.1016/j.ibmb.2018.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/12/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
Wolbachia are endosymbiotic bacteria present in a wide range of invertebrates. Although their dramatic effects on host reproductive biology have been well studied, little is known about the effects of Wolbachia on the learning and memory capacity (LMC) of hosts, despite their distribution in the host nervous system, including brain. In this study, we found that Wolbachia infection significantly enhanced LMC in both Drosophila melanogaster and D. simulans. Expression of LMC-related genes was significantly increased in the head of D. melanogaster infected with the wMel strain, and among these genes, crebA was up-regulated the most. Knockdown of crebA in Wolbachia-infected flies significantly decreased LMC, while overexpression of crebA in Wolbachia-free flies significantly enhanced the LMC of flies. More importantly, a microRNA (miRNA), dme-miR-92b, was identified to be complementary to the 3'UTR of crebA. Wolbachia infection was correlated with reduced expression of dme-miR-92b in D. melanogaster, and dme-miR-92b negatively regulated crebA through binding to its 3'UTR region. Overexpression of dme-miR-92b in Wolbachia-infected flies by microinjection of agomirs caused a significant decrease in crebA expression and LMC, while inhibition of dme-miR-92b in Wolbachia-free flies by microinjection of antagomirs resulted in a significant increase in crebA expression and LMC. These results suggest that Wolbachia may improve LMC in Drosophila by altering host gene expression through a miRNA-target pathway. Our findings help better understand the host-endosymbiont interactions and, in particular, the impact of Wolbachia on cognitive processes in invertebrate hosts.
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Affiliation(s)
- Jie Bi
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, PR China
| | - Ya Zheng
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, PR China
| | - Rui-Fang Wang
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, PR China
| | - Hui Ai
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, PR China
| | - Paula R Haynes
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jeremy C Brownlie
- School of Natural Science, Griffith University, Nathan, QLD 4111, Australia
| | - Xiao-Qiang Yu
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, PR China; School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
| | - Yu-Feng Wang
- School of Life Sciences, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, PR China.
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55
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Asselin AK, Villegas-Ospina S, Hoffmann AA, Brownlie JC, Johnson KN. Contrasting Patterns of Virus Protection and Functional Incompatibility Genes in Two Conspecific Wolbachia Strains from Drosophila pandora. Appl Environ Microbiol 2019; 85:e02290-18. [PMID: 30552191 PMCID: PMC6384105 DOI: 10.1128/aem.02290-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/10/2018] [Indexed: 12/16/2022] Open
Abstract
Wolbachia infections can present different phenotypes in hosts, including different forms of reproductive manipulation and antiviral protection, which may influence infection dynamics within host populations. In populations of Drosophila pandora two distinct Wolbachia strains coexist, each manipulating host reproduction: strain wPanCI causes cytoplasmic incompatibility (CI), whereas strain wPanMK causes male killing (MK). CI occurs when a Wolbachia-infected male mates with a female not infected with a compatible type of Wolbachia, leading to nonviable offspring. wPanMK can rescue wPanCI-induced CI but is unable to induce CI. The antiviral protection phenotypes provided by the wPanCI and wPanMK infections were characterized; the strains showed differential protection phenotypes, whereby cricket paralysis virus (CrPV)-induced mortality was delayed in flies infected with wPanMK but enhanced in flies infected with wPanCI compared to their respective Wolbachia-cured counterparts. Homologs of the cifA and cifB genes involved in CI identified in wPanMK and wPanCI showed a high degree of conservation; however, the CifB protein in wPanMK is truncated and is likely nonfunctional. The presence of a likely functional CifA in wPanMK and wPanMK's ability to rescue wPanCI-induced CI are consistent with the recent confirmation of CifA's involvement in CI rescue, and the absence of a functional CifB protein further supports its involvement as a CI modification factor. Taken together, these findings indicate that wPanCI and wPanMK have different relationships with their hosts in terms of their protective and CI phenotypes. It is therefore likely that different factors influence the prevalence and dynamics of these coinfections in natural Drosophila pandora hosts.IMPORTANCEWolbachia strains are common endosymbionts in insects, with multiple strains often coexisting in the same species. The coexistence of multiple strains is poorly understood but may rely on Wolbachia organisms having diverse phenotypic effects on their hosts. As Wolbachia is increasingly being developed as a tool to control disease transmission and suppress pest populations, it is important to understand the ways in which multiple Wolbachia strains persist in natural populations and how these might then be manipulated. We have therefore investigated viral protection and the molecular basis of cytoplasmic incompatibility in two coexisting Wolbachia strains with contrasting effects on host reproduction.
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Affiliation(s)
- Angelique K Asselin
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Simon Villegas-Ospina
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Ary A Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jeremy C Brownlie
- School of Environment and Science, Griffith University, Brisbane, Queensland, Australia
| | - Karyn N Johnson
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
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56
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Beckmann JF, Bonneau M, Chen H, Hochstrasser M, Poinsot D, Merçot H, Weill M, Sicard M, Charlat S. The Toxin-Antidote Model of Cytoplasmic Incompatibility: Genetics and Evolutionary Implications. Trends Genet 2019; 35:175-185. [PMID: 30685209 DOI: 10.1016/j.tig.2018.12.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
Abstract
Wolbachia bacteria inhabit the cells of about half of all arthropod species, an unparalleled success stemming in large part from selfish invasive strategies. Cytoplasmic incompatibility (CI), whereby the symbiont makes itself essential to embryo viability, is the most common of these and constitutes a promising weapon against vector-borne diseases. After decades of theoretical and experimental struggle, major recent advances have been made toward a molecular understanding of this phenomenon. As pieces of the puzzle come together, from yeast and Drosophila fly transgenesis to CI diversity patterns in natural mosquito populations, it becomes clearer than ever that the CI induction and rescue stem from a toxin-antidote (TA) system. Further, the tight association of the CI genes with prophages provides clues to the possible evolutionary origin of this phenomenon and the levels of selection at play.
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Affiliation(s)
- John F Beckmann
- Auburn University, Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn, AL 36849, USA; Equal contribution
| | - Manon Bonneau
- Institut des Sciences de l'Evolution de Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), Montpellier, France; Equal contribution
| | - Hongli Chen
- Yale University, Department of Molecular Biophysics and Biochemistry, 266 Whitney Avenue, New Haven, CT 06511, USA
| | - Mark Hochstrasser
- Yale University, Department of Molecular Biophysics and Biochemistry, 266 Whitney Avenue, New Haven, CT 06511, USA
| | - Denis Poinsot
- Université Rennes 1, Institut de Génétique, Environnement, et Protection des Plantes (IGEPP), Campus Beaulieu, 35042 Rennes, France
| | - Hervé Merçot
- Sorbonne Université, Université Pierre et Marie Curie (UPMC) Université Paris 06, CNRS, Institut de Biologie Paris Seine, Evolution Paris Seine (IBPS, EPS), 7-9 Quai St-Bernard, 75005 Paris, France
| | - Mylène Weill
- Institut des Sciences de l'Evolution de Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Mathieu Sicard
- Institut des Sciences de l'Evolution de Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), Montpellier, France.
| | - Sylvain Charlat
- CNRS, University of Lyon, Laboratoire de Biométrie et Biologie Evolutive, 16 rue Raphael Dubois, 69622 Villeurbanne, France.
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57
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Lindsey ARI, Rice DW, Bordenstein SR, Brooks AW, Bordenstein SR, Newton ILG. Evolutionary Genetics of Cytoplasmic Incompatibility Genes cifA and cifB in Prophage WO of Wolbachia. Genome Biol Evol 2018; 10:434-451. [PMID: 29351633 PMCID: PMC5793819 DOI: 10.1093/gbe/evy012] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
The bacterial endosymbiont Wolbachia manipulates arthropod reproduction to facilitate its maternal spread through host populations. The most common manipulation is cytoplasmic incompatibility (CI): Wolbachia-infected males produce modified sperm that cause embryonic mortality, unless rescued by embryos harboring the same Wolbachia. The genes underlying CI, cifA and cifB, were recently identified in the eukaryotic association module of Wolbachia’s prophage WO. Here, we use transcriptomic and genomic approaches to address three important evolutionary facets of the cif genes. First, we assess whether or not cifA and cifB comprise a classic toxin–antitoxin operon in wMel and show that the two genes exhibit striking, transcriptional differences across host development. They can produce a bicistronic message despite a predicted hairpin termination element in their intergenic region. Second, cifA and cifB strongly coevolve across the diversity of phage WO. Third, we provide new domain and functional predictions across homologs within Wolbachia, and show that amino acid sequences vary substantially across the genus. Finally, we investigate conservation of cifA and cifB and find frequent degradation and loss of the genes in strains that no longer induce CI. Taken together, we demonstrate that cifA and cifB exhibit complex transcriptional regulation in wMel, provide functional annotations that broaden the potential mechanisms of CI induction, and report recurrent erosion of cifA and cifB in non-CI strains, thus expanding our understanding of the most widespread form of reproductive parasitism.
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Affiliation(s)
| | - Danny W Rice
- Department of Biology, Indiana University, Bloomington
| | | | - Andrew W Brooks
- Department of Biological Sciences, Vanderbilt University.,Vanderbilt Genetics Institute, Vanderbilt University
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University.,Vanderbilt Genetics Institute, Vanderbilt University.,Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University.,Department of Pathology, Microbiology and Immunology, Vanderbilt University
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58
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Bonneau M, Landmann F, Labbé P, Justy F, Weill M, Sicard M. The cellular phenotype of cytoplasmic incompatibility in Culex pipiens in the light of cidB diversity. PLoS Pathog 2018; 14:e1007364. [PMID: 30321239 PMCID: PMC6201942 DOI: 10.1371/journal.ppat.1007364] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/25/2018] [Accepted: 09/28/2018] [Indexed: 11/18/2022] Open
Abstract
Wolbachia are maternally inherited endosymbiotic bacteria, widespread among arthropods thanks to host reproductive manipulations that increase their prevalence into host populations. The most commonly observed manipulation is cytoplasmic incompatibility (CI). CI leads to embryonic death in crosses between i) infected males and uninfected females and ii) individuals infected with incompatible Wolbachia strains. CI can be conceptualized as a toxin-antidote system where a toxin deposited by Wolbachia in the sperm would induce embryonic death unless countered by an antidote produced by Wolbachia present in the eggs. In Drosophila melanogaster, transgenic expression of Wolbachia effector cidB revealed its function of CI-inducing toxin. Moreover in Culex pipiens, the diversity of cidB variants present in wPip strains accounts for the diversity in crossing-types. We conducted cytological analyses to determine the CI mechanisms that lead to embryonic death in C. pipiens, and assess whether diversity in crossing-types could be based on variations in these mechanisms. We revealed that paternal chromatin condensation and segregation defects during the first embryonic division are always responsible for embryonic death. The strongest observed defects lead to an exclusion of the paternal chromatin from the first zygotic division, resulting in haploid embryos unable to hatch. The proportion of unhatched haploid embryos, developing with only maternal chromatin, which reflects the frequency of strong defects can be considered as a proxy of CI intensity at the cellular level. We thus studied the putative effect of variations in crossing types and cidB diversification on CI defects intensity. Incompatible crosses involving distinct wPip strains revealed that CI defects intensity depends on the Wolbachia strains hosted by the males and is linked to the diversity of cidB genes harbored in their genomes. These results support that, additionally to its implication in C. pipiens crossing type variability, cidB diversification also influences the strength of CI embryonic defects. In some crosses, mosquito males belonging to the species Culex pipiens prevent their females from having live progenies. This phenomenon called cytoplasmic incompatibility (CI) is caused by intracellular bacteria named Wolbachia. CI occurs when males infected with Wolbachia fertilize females infected with genetically distinct incompatible Wolbachia resulting in the death of all the embryos. At the world scale, crossing relationships between C. pipiens are quite puzzling. Despite this complexity in crossing relationships and the diversity of cidB genes involved in CI mechanisms in C. pipiens, we demonstrate a single shared CI cellular phenotype leading to the death of the embryos: the paternal chromatin exclusion from the first embryonic division. If paternal chromatin is fully excluded, embryos developed with haploid set of chromosomes. We show that the frequency of haploid development varies according to the Wolbachia strains hosted by the males which differ in the cidB variants harbored in their genomes. Absence of Wolbachia in the eggs totally block haploid development showing that maternal Wolbachia presence interplays with CI mechanisms in a way that allows haploid development to occur. Understanding CI mechanism in mosquitoes is the corner stone to build new sustainable and adaptable Wolbachia based strategies for vector control.
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Affiliation(s)
- Manon Bonneau
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | | | - Pierrick Labbé
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Fabienne Justy
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Mylène Weill
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Mathieu Sicard
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
- * E-mail:
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59
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Abstract
The World Health Organization recommended pilot deployment of Wolbachia-infected mosquitoes to curb viral transmission to humans. Releases of mosquitoes are underway worldwide because Wolbachia can block replication of these pathogenic viruses and deterministically spread by a drive system termed cytoplasmic incompatibility (CI). Despite extensive research, the underlying genetic basis of CI remains only half-solved. We recently reported that two prophage WO genes recapitulate the modification component of CI in a released strain for vector control. Here we show that one of these genes underpins rescue of CI. Together, our results reveal the complete genetic basis of this selfish trait and pave the way for future studies exploring WO prophage genes as adjuncts or alternatives to current control efforts. Wolbachia are maternally inherited, intracellular bacteria at the forefront of vector control efforts to curb arbovirus transmission. In international field trials, the cytoplasmic incompatibility (CI) drive system of wMel Wolbachia is deployed to replace target vector populations, whereby a Wolbachia-induced modification of the sperm genome kills embryos. However, Wolbachia in the embryo rescue the sperm genome impairment, and therefore CI results in a strong fitness advantage for infected females that transmit the bacteria to offspring. The two genes responsible for the wMel-induced sperm modification of CI, cifA and cifB, were recently identified in the eukaryotic association module of prophage WO, but the genetic basis of rescue is unresolved. Here we use transgenic and cytological approaches to demonstrate that maternal cifA expression independently rescues CI and nullifies embryonic death caused by wMel Wolbachia in Drosophila melanogaster. Discovery of cifA as the rescue gene and previously one of two CI induction genes establishes a “Two-by-One” model that underpins the genetic basis of CI. Results highlight the central role of prophage WO in shaping Wolbachia phenotypes that are significant to arthropod evolution and vector control.
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60
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Conflict in the Intracellular Lives of Endosymbionts and Viruses: A Mechanistic Look at Wolbachia-Mediated Pathogen-blocking. Viruses 2018; 10:v10040141. [PMID: 29561780 PMCID: PMC5923435 DOI: 10.3390/v10040141] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/14/2018] [Accepted: 03/20/2018] [Indexed: 12/16/2022] Open
Abstract
At the forefront of vector control efforts are strategies that leverage host-microbe associations to reduce vectorial capacity. The most promising of these efforts employs Wolbachia, a maternally transmitted endosymbiotic bacterium naturally found in 40% of insects. Wolbachia can spread through a population of insects while simultaneously inhibiting the replication of viruses within its host. Despite successes in using Wolbachia-transfected mosquitoes to limit dengue, Zika, and chikungunya transmission, the mechanisms behind pathogen-blocking have not been fully characterized. Firstly, we discuss how Wolbachia and viruses both require specific host-derived structures, compounds, and processes to initiate and maintain infection. There is significant overlap in these requirements, and infection with either microbe often manifests as cellular stress, which may be a key component of Wolbachia’s anti-viral effect. Secondly, we discuss the current understanding of pathogen-blocking through this lens of cellular stress and develop a comprehensive view of how the lives of Wolbachia and viruses are fundamentally in conflict with each other. A thorough understanding of the genetic and cellular determinants of pathogen-blocking will significantly enhance the ability of vector control programs to deploy and maintain effective Wolbachia-mediated control measures.
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61
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Gebiola M, Giorgini M, Kelly SE, Doremus MR, Ferree PM, Hunter MS. Cytological analysis of cytoplasmic incompatibility induced by Cardinium suggests convergent evolution with its distant cousin Wolbachia. Proc Biol Sci 2018; 284:rspb.2017.1433. [PMID: 28878066 DOI: 10.1098/rspb.2017.1433] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 07/25/2017] [Indexed: 01/06/2023] Open
Abstract
Cytoplasmic incompatibility (CI) is a conditional sterility in numerous arthropods that is caused by inherited, intracellular bacteria such as Wolbachia Matings between males carrying CI-inducing Wolbachia and uninfected females, or between males and females infected with different Wolbachia strains, result in progeny that die during very early embryogenesis. Multiple studies in diploid (Drosophila) and haplodiploid (Nasonia) insects have shown that CI-Wolbachia cause a failure of the paternally derived chromatin from resolving into distinct chromosomes. This leads to the formation of chromatin bridges and other mitotic defects as early as the first mitotic division, and to early mitotic arrest. It is currently unknown if CI-inducing symbionts other than Wolbachia affect similar cellular processes. Here, we investigated CI caused by an unrelated bacterium, Cardinium, which naturally infects a parasitic wasp, Encarsia suzannae CI crosses in this host-symbiont system resulted in early mitotic defects including asynchrony of paternal and maternal chromosome sets as they enter mitosis, chromatin bridges and improper chromosome segregation that spanned across multiple mitotic divisions, triggering embryonic death through accumulated aneuploidy. We highlight small differences with CI-Wolbachia, which could be due to the underlying CI mechanism or host-specific effects. Our results suggest a convergence of CI-related cellular phenotypes between these two unrelated symbionts.
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Affiliation(s)
- Marco Gebiola
- Department of Entomology, The University of Arizona, Tucson, AZ 85721, USA .,CNR-Istituto per la Protezione Sostenibile delle Piante, Portici, Italy
| | - Massimo Giorgini
- CNR-Istituto per la Protezione Sostenibile delle Piante, Portici, Italy
| | - Suzanne E Kelly
- Department of Entomology, The University of Arizona, Tucson, AZ 85721, USA
| | - Matthew R Doremus
- Department of Entomology, The University of Arizona, Tucson, AZ 85721, USA.,Graduate Interdisciplinary Program in Entomology and Insect Science, The University of Arizona, Tucson, AZ 85721, USA
| | - Patrick M Ferree
- W. M. Keck Science Department, The Claremont Colleges, Claremont, CA 91711, USA
| | - Martha S Hunter
- Department of Entomology, The University of Arizona, Tucson, AZ 85721, USA
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62
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The potential role of Wolbachia in controlling the transmission of emerging human arboviral infections. Curr Opin Infect Dis 2018; 30:108-116. [PMID: 27849636 PMCID: PMC5325245 DOI: 10.1097/qco.0000000000000342] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Purpose of review Wolbachia is a genus of Gram-negative intracellular bacteria that is naturally found in more than half of all arthropod species. These bacteria cannot only reduce the fitness and the reproductive capacities of arthropod vectors, but also increase their resistance to arthropod-borne viruses (arboviruses). This article reviews the evidence supporting a Wolbachia-based strategy for controlling the transmission of dengue and other arboviral infections. Recent findings Studies conducted 1 year after the field release of Wolbachia-infected mosquitoes in Australia have demonstrated the suppression of dengue virus (DENV) replication in and dissemination by mosquitoes. Recent mathematical models show that this strategy could reduce the transmission of DENV by 70%. Consequently, the WHO is encouraging countries to boost the development and implementation of Wolbachia-based prevention strategies against other arboviral infections. However, the evidence regarding the efficacy of Wolbachia to prevent the transmission of other arboviral infections is still limited to an experimental framework with conflicting results in some cases. There is a need to demonstrate the efficacy of such strategies in the field under various climatic conditions, to select the Wolbachia strain that has the best pathogen interference/spread trade-off, and to continue to build community acceptance. Summary Wolbachia represents a promising tool for controlling the transmission of arboviral infections that needs to be developed further. Long-term environmental monitoring will be necessary for timely detection of potential changes in Wolbachia/vector/virus interactions.
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63
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Ju JF, Hoffmann AA, Zhang YK, Duan XZ, Guo Y, Gong JT, Zhu WC, Hong XY. Wolbachia-induced loss of male fertility is likely related to branch chain amino acid biosynthesis and iLvE in Laodelphax striatellus. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 85:11-20. [PMID: 28412513 DOI: 10.1016/j.ibmb.2017.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/23/2017] [Accepted: 04/10/2017] [Indexed: 06/07/2023]
Abstract
Wolbachia are endosymbionts that infect many species of arthropods and nematodes. Wolbachia-induced cytoplasmic incompatibility (CI) is the most common phenotype in affected hosts, involving embryonic lethality in crosses between Wolbachia-infected males and uninfected females. The molecular mechanisms underlying this phenomenon are currently unclear. Here we examine the molecular correlates of the Wolbachia infection in Laodelphax striatellus (Fallén), an important rice pest, where embryonic lethality is strong and almost complete. We compared the gene expression of 4-day-old Wolbachia-infected and uninfected L. striatellus testes to identify candidate genes for paternal-effect embryonic lethality induction. Based on microarray analysis, iLvE was the most down-regulated gene; this gene mediates branched-chain amino acid (BCAA) biosynthesis and participates in many processes related to reproductive performance. After knocking down iLvE by RNAi in uninfected male L. striatellus, male fertility was reduced, leading to a decrease in embryo hatching rates, but fertility was rescued in crosses between these males and Wolbachia-infected females. Removal of BCAA in chemically-defined diets of uninfected males also led to a loss of male fertility. Low amino acid nutrition may enhance exposure time of sperm to Wolbachia in the testes to affect adult reproduction in L. striatellus by reducing the number of sperm transferred per mating by males. These results indicate that Wolbachia may decrease male fertility in L. striatellus by acting on iLvE, a key factor of BCAA biosynthesis, and delaying sperm maturation.
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Affiliation(s)
- Jia-Fei Ju
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Ary A Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Victoria 3010, Australia.
| | - Yan-Kai Zhang
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Xing-Zhi Duan
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Yan Guo
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Jun-Tao Gong
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Wen-Chao Zhu
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Xiao-Yue Hong
- Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
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64
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Aldrich JC, Ferree PM. Genome Silencing and Elimination: Insights from a "Selfish" B Chromosome. Front Genet 2017; 8:50. [PMID: 28487723 PMCID: PMC5403880 DOI: 10.3389/fgene.2017.00050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/10/2017] [Indexed: 02/04/2023] Open
Abstract
B chromosomes are non-essential components of numerous plant and animal genomes. Because many of these "extra" chromosomes enhance their own transmission in ways that are detrimental to the rest of the genome, they can be thought of as genome parasites. An extreme example is a paternally inherited B chromosome known as paternal sex ratio (PSR), which is found in natural populations of the jewel wasp Nasonia vitripennis. In order to ensure its own propagation, PSR severely biases the wasp sex ratio by converting diploid female-destined embryos into transmitting haploid males. This action occurs at the expense of the other paternally inherited chromosomes, which fail to resolve during the first round of division and are thus eliminated. Recent work has revealed that paternal genome elimination by PSR occurs through the disruption of a number of specific histone post-translational modifications, suggesting a central role for chromatin regulation in this phenomenon. In this review, we describe these recent advances in the light of older ones and in the context of what is currently understood about the molecular mechanisms of targeted genome silencing and elimination in other systems.
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Affiliation(s)
| | - Patrick M. Ferree
- W.M. Keck Science Department, Claremont McKenna College, Pitzer College and Scripps College, ClaremontCA, USA
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65
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A Wolbachia deubiquitylating enzyme induces cytoplasmic incompatibility. Nat Microbiol 2017; 2:17007. [PMID: 28248294 PMCID: PMC5336136 DOI: 10.1038/nmicrobiol.2017.7] [Citation(s) in RCA: 246] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/10/2017] [Indexed: 12/29/2022]
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66
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Prophage WO genes recapitulate and enhance Wolbachia-induced cytoplasmic incompatibility. Nature 2017; 543:243-247. [PMID: 28241146 PMCID: PMC5358093 DOI: 10.1038/nature21391] [Citation(s) in RCA: 286] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 01/12/2017] [Indexed: 02/05/2023]
Abstract
The genus Wolbachia is an archetype of maternally inherited intracellular bacteria that infect the germline of numerous invertebrate species worldwide. They can selfishly alter arthropod sex ratios and reproductive strategies to increase the proportion of the infected matriline in the population. The most common reproductive manipulation is cytoplasmic incompatibility (CI), which results in embryonic lethality in crosses between infected males and uninfected females. Females infected with the same Wolbachia strain rescue this lethality. Despite more than 40 years of research1 and relevance to symbiont-induced speciation2,3, as well as control of arbovirus vectors4,5,6 and agricultural pests7, the bacterial genes underlying CI remain unknown. Here, we use comparative and transgenic approaches to demonstrate that two differentially transcribed, codiverging genes in the eukaryotic association module of prophage WO8 from Wolbachia strain wMel recapitulate and enhance CI. Dual expression in transgenic, uninfected males of Drosophila melanogaster crossed to uninfected females causes embryonic lethality. Each gene additively augments embryonic lethality in infected males crossed to uninfected females. Lethality associates with embryonic defects that parallel those of wild type CI and is notably rescued by wMel-infected embryos in all cases. The discovery of cytoplasmic incompatibility factor genes cifA and cifB pioneers genetic studies of prophage WO-induced reproductive manipulations and informs Wolbachia’s ongoing utility to control dengue and Zika transmission to humans.
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67
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Affiliation(s)
- William Sullivan
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, California 95064, USA
| | - Scott L O'Neill
- Institute of Vector-Borne Disease, Monash University, Clayton 3800, Australia
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68
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Caragata EP, Pais FS, Baton LA, Silva JBL, Sorgine MHF, Moreira LA. The transcriptome of the mosquito Aedes fluviatilis (Diptera: Culicidae), and transcriptional changes associated with its native Wolbachia infection. BMC Genomics 2017; 18:6. [PMID: 28049478 PMCID: PMC5210266 DOI: 10.1186/s12864-016-3441-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/19/2016] [Indexed: 12/21/2022] Open
Abstract
Background Wolbachia is a bacterial endosymbiont that naturally infects a wide range of insect species, and causes drastic changes to host biology. Stable infections of Wolbachia in mosquitoes can inhibit infection with medically important pathogens such as dengue virus and malaria-causing Plasmodium parasites. However, some native Wolbachia strains can enhance infection with certain pathogens, as is the case for the mosquito Aedes fluviatilis, where infection with Plasmodium gallinaceum is enhanced by the native wFlu Wolbachia strain. To better understand the biological interactions between mosquitoes and native Wolbachia infections, and to investigate the process of pathogen enhancement, we used RNA-Seq to generate the transcriptome of Ae. fluviatilis with and without Wolbachia infection. Results In total, we generated 22,280,160 Illumina paired-end reads from Wolbachia-infected and uninfected mosquitoes, and used these to make a de novo transcriptome assembly, resulting in 58,013 contigs with a median sequence length of 443 bp and an N50 of 2454 bp. Contigs were annotated through local alignments using BlastX, and associated with both gene ontology and KEGG orthology terms. Through baySeq, we identified 159 contigs that were significantly upregulated due to Wolbachia infection, and 98 that were downregulated. Critically, we saw no changes to Toll or IMD immune gene transcription, but did see evidence that wFlu infection altered the expression of several bacterial recognition genes, and immune-related genes that could influence Plasmodium infection. wFlu infection also had a widespread effect on a number of host physiological processes including protein, carbohydrate and lipid metabolism, and oxidative stress. We then compared our data set with transcriptomic data for other Wolbachia infections in Aedes aegypti, and identified a core set of 15 gene groups associated with Wolbachia infection in mosquitoes. Conclusions While the scale of transcriptional changes associated with wFlu infection might be small, the scope is rather large, which confirms that native Wolbachia infections maintain intricate molecular relationships with their mosquito hosts even after lengthy periods of co-evolution. We have also identified several potential means through which wFlu infection might influence Plasmodium infection in Ae. fluviatilis, and these genes should form the basis of future investigation into the enhancement of Plasmodium by Wolbachia. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3441-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- E P Caragata
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fiocruz, Belo Horizonte, Minas Gerais, Brazil
| | - F S Pais
- Grupo de Informática de Biossistemas e Genômica, Centro de Pesquisas René Rachou - Fiocruz, Belo Horizonte, Minas Gerais, Brazil
| | - L A Baton
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fiocruz, Belo Horizonte, Minas Gerais, Brazil
| | - J B L Silva
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fiocruz, Belo Horizonte, Minas Gerais, Brazil
| | - M H F Sorgine
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - L A Moreira
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fiocruz, Belo Horizonte, Minas Gerais, Brazil.
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69
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Male-killing symbiont damages host's dosage-compensated sex chromosome to induce embryonic apoptosis. Nat Commun 2016; 7:12781. [PMID: 27650264 PMCID: PMC5036004 DOI: 10.1038/ncomms12781] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/01/2016] [Indexed: 12/02/2022] Open
Abstract
Some symbiotic bacteria are capable of interfering with host reproduction in selfish ways. How such bacteria can manipulate host's sex-related mechanisms is of fundamental interest encompassing cell, developmental and evolutionary biology. Here, we uncover the molecular and cellular mechanisms underlying Spiroplasma-induced embryonic male lethality in Drosophila melanogaster. Transcriptomic analysis reveals that many genes related to DNA damage and apoptosis are up-regulated specifically in infected male embryos. Detailed genetic and cytological analyses demonstrate that male-killing Spiroplasma causes DNA damage on the male X chromosome interacting with the male-specific lethal (MSL) complex. The damaged male X chromosome exhibits a chromatin bridge during mitosis, and bridge breakage triggers sex-specific abnormal apoptosis via p53-dependent pathways. Notably, the MSL complex is not only necessary but also sufficient for this cytotoxic process. These results highlight symbiont's sophisticated strategy to target host's sex chromosome and recruit host's molecular cascades toward massive apoptosis in a sex-specific manner. Symbiotic bacteria are able to interfere with host reproduction in ways that are detrimental to the host organism. Here the authors show that Spiroplasma induces DNA damage on the male X chromosome in Drosophila, causing sex-specific apoptosis.
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70
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McLysaght A, Hurst LD. Open questions in the study of de novo genes: what, how and why. Nat Rev Genet 2016; 17:567-78. [PMID: 27452112 DOI: 10.1038/nrg.2016.78] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The study of de novo protein-coding genes is maturing from the ad hoc reporting of individual cases to the systematic analysis of extensive genomic data from several species. We identify three key challenges for this emerging field: understanding how best to identify de novo genes, how they arise and why they spread. We highlight the intellectual challenges of understanding how a de novo gene becomes integrated into pre-existing functions and becomes essential. We suggest that, as with protein sequence evolution, antagonistic co-evolution may be key to de novo gene evolution, particularly for new essential genes and new cancer-associated genes.
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Affiliation(s)
- Aoife McLysaght
- The Smurfit Institute of Genetics, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Laurence D Hurst
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, Somerset BA2 7AY, UK
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71
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Abstract
The union of haploid gametes at fertilization initiates the formation of the diploid zygote in sexually reproducing animals. This founding event of embryogenesis includes several fascinating cellular and nuclear processes, such as sperm-egg cellular interactions, sperm chromatin remodelling, centrosome formation or pronuclear migration. In comparison with other aspects of development, the exploration of animal fertilization at the functional level has remained so far relatively limited, even in classical model organisms. Here, we have reviewed our current knowledge of fertilization in Drosophila melanogaster, with a special emphasis on the genes involved in the complex transformation of the fertilizing sperm nucleus into a replicated set of paternal chromosomes.
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Affiliation(s)
- Benjamin Loppin
- Laboratoire de Biométrie et Biologie Evolutive, CNRS UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Raphaëlle Dubruille
- Laboratoire de Biométrie et Biologie Evolutive, CNRS UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Béatrice Horard
- Laboratoire de Biométrie et Biologie Evolutive, CNRS UMR5558, Université Claude Bernard Lyon 1, Villeurbanne, France
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72
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Johnson KN. The Impact of Wolbachia on Virus Infection in Mosquitoes. Viruses 2015; 7:5705-17. [PMID: 26556361 PMCID: PMC4664976 DOI: 10.3390/v7112903] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/07/2015] [Accepted: 10/22/2015] [Indexed: 12/16/2022] Open
Abstract
Mosquito-borne viruses such as dengue, West Nile and chikungunya viruses cause significant morbidity and mortality in human populations. Since current methods are not sufficient to control disease occurrence, novel methods to control transmission of arboviruses would be beneficial. Recent studies have shown that virus infection and transmission in insects can be impeded by co-infection with the bacterium Wolbachia pipientis. Wolbachia is a maternally inherited endosymbiont that is commonly found in insects, including a number of mosquito vector species. In Drosophila, Wolbachia mediates antiviral protection against a broad range of RNA viruses. This discovery pointed to a potential strategy to interfere with mosquito transmission of arboviruses by artificially infecting mosquitoes with Wolbachia. This review outlines research on the prevalence of Wolbachia in mosquito vector species and the impact of antiviral effects in both naturally and artificially Wolbachia-infected mosquitoes.
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Affiliation(s)
- Karyn N Johnson
- School of Biological Sciences, The University of Queensland, Brisbane 4072, Australia.
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73
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Zug R, Hammerstein P. Wolbachia and the insect immune system: what reactive oxygen species can tell us about the mechanisms of Wolbachia-host interactions. Front Microbiol 2015; 6:1201. [PMID: 26579107 PMCID: PMC4621438 DOI: 10.3389/fmicb.2015.01201] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/15/2015] [Indexed: 01/06/2023] Open
Abstract
Wolbachia are intracellular bacteria that infect a vast range of arthropod species, making them one of the most prevalent endosymbionts in the world. Wolbachia's stunning evolutionary success is mostly due to their reproductive parasitism but also to mutualistic effects such as increased host fecundity or protection against pathogens. However, the mechanisms underlying Wolbachia phenotypes, both parasitic and mutualistic, are only poorly understood. Moreover, it is unclear how the insect immune system is involved in these phenotypes and why it is not more successful in eliminating the bacteria. Here we argue that reactive oxygen species (ROS) are likely to be key in elucidating these issues. ROS are essential players in the insect immune system, and Wolbachia infection can affect ROS levels in the host. Based on recent findings, we elaborate a hypothesis that considers the different effects of Wolbachia on the oxidative environment in novel vs. native hosts. We propose that newly introduced Wolbachia trigger an immune response and cause oxidative stress, whereas in coevolved symbioses, infection is not associated with oxidative stress, but rather with restored redox homeostasis. Redox homeostasis can be restored in different ways, depending on whether Wolbachia or the host is in charge. This hypothesis offers a mechanistic explanation for several of the observed Wolbachia phenotypes.
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Affiliation(s)
- Roman Zug
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
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74
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Pontier SM, Schweisguth F. A Wolbachia-Sensitive Communication between Male and Female Pupae Controls Gamete Compatibility in Drosophila. Curr Biol 2015; 25:2339-48. [PMID: 26344089 DOI: 10.1016/j.cub.2015.07.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/06/2015] [Accepted: 07/22/2015] [Indexed: 01/22/2023]
Abstract
Gamete compatibility is fundamental to sexual reproduction. Wolbachia are maternally inherited endosymbiotic bacteria that manipulate gamete compatibility in many arthropod species. In Drosophila, the fertilization of uninfected eggs by sperm from Wolbachia-infected males often results in early developmental arrest. This gamete incompatibility is called cytoplasmic incompatibility (CI). CI is highest in young males, suggesting that Wolbachia affect sperm properties during male development. Here, we show that Wolbachia modulate testis development. Unexpectedly, this effect was associated with Wolbachia infection in females, not males. This raised the possibility that females influenced testis development by communicating with males prior to adulthood. Using a combinatorial rearing protocol, we provide evidence for such a female-to-male communication during metamorphosis. This communication involves the perception of female pheromones by male olfactory receptors. We found that this communication determines the compatibility range of sperm. Wolbachia interfere with this female-to-male communication through changes in female pheromone production. Strikingly, restoring this communication partially suppressed CI in Wolbachia-infected males. We further identified a reciprocal male-to-female communication at metamorphosis that restricts the compatibility range of female gametes. Wolbachia also perturb this communication by feminizing male pheromone production. Thus, Wolbachia broaden the compatibility range of eggs, promoting thereby the reproductive success of Wolbachia-infected females. We conclude that pheromone communication between pupae regulates gamete compatibility and is sensitive to Wolbachia in Drosophila.
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Affiliation(s)
- Stéphanie M Pontier
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France; CNRS, URA2578, 75015 Paris, France.
| | - François Schweisguth
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 75015 Paris, France; CNRS, URA2578, 75015 Paris, France
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75
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Yuan LL, Chen X, Zong Q, Zhao T, Wang JL, Zheng Y, Zhang M, Wang Z, Brownlie JC, Yang F, Wang YF. Quantitative Proteomic Analyses of Molecular Mechanisms Associated with Cytoplasmic Incompatibility in Drosophila melanogaster Induced by Wolbachia. J Proteome Res 2015. [DOI: 10.1021/acs.jproteome.5b00191] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Lin-Ling Yuan
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
| | - Xiulan Chen
- Key
Laboratory of Protein and Peptide Pharmaceuticals and Laboratory of
Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Qiong Zong
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
| | - Ting Zhao
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
| | - Jia-Lin Wang
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
| | - Ya Zheng
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
| | - Ming Zhang
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
| | - Zailong Wang
- Novartis Pharmaceuticals, East Hanover, New Jersey 07936, United States
| | - Jeremy C. Brownlie
- School
of Natural Science, Griffith University, Nathan, Queensland 4111, Australia
| | - Fuquan Yang
- Key
Laboratory of Protein and Peptide Pharmaceuticals and Laboratory of
Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Yu-Feng Wang
- Hubei
Key Laboratory of Genetic Regulation and Integrative Biology, School
of Life Sciences, Central China Normal University, Wuhan 430079, People’s Republic of China
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76
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Levine MT, Vander Wende HM, Malik HS. Mitotic fidelity requires transgenerational action of a testis-restricted HP1. eLife 2015; 4:e07378. [PMID: 26151671 PMCID: PMC4491702 DOI: 10.7554/elife.07378] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 06/08/2015] [Indexed: 01/02/2023] Open
Abstract
Sperm-packaged DNA must undergo extensive reorganization to ensure its timely participation in embryonic mitosis. Whereas maternal control over this remodeling is well described, paternal contributions are virtually unknown. In this study, we show that Drosophila melanogaster males lacking Heterochromatin Protein 1E (HP1E) sire inviable embryos that undergo catastrophic mitosis. In these embryos, the paternal genome fails to condense and resolve into sister chromatids in synchrony with the maternal genome. This delay leads to a failure of paternal chromosomes, particularly the heterochromatin-rich sex chromosomes, to separate on the first mitotic spindle. Remarkably, HP1E is not inherited on mature sperm chromatin. Instead, HP1E primes paternal chromosomes during spermatogenesis to ensure faithful segregation post-fertilization. This transgenerational effect suggests that maternal control is necessary but not sufficient for transforming sperm DNA into a mitotically competent pronucleus. Instead, paternal action during spermiogenesis exerts post-fertilization control to ensure faithful chromosome segregation in the embryo. DOI:http://dx.doi.org/10.7554/eLife.07378.001 The genetic information of cells is packaged into structures called chromosomes, which are made up of long strands of DNA that are wrapped around proteins to form a structure called chromatin. The cells of most animals contain two copies of every chromosome, but the egg and sperm cells contain only one copy. This means that when an egg fuses with a sperm cell during fertilization, the resulting ‘zygote’ will contain two copies of each chromosome—one inherited from the mother, and one from the father. These chromosomes duplicate and divide many times within the developing embryo in a process known as mitosis. The first division of the zygote is particularly complicated, as the egg and sperm chromosomes must go through extensive—and yet different—chromatin reorganization processes. For instance, paternal DNA is inherited via sperm, where specialized sperm proteins package the DNA more tightly than in the maternal DNA, which is packaged by histone proteins used throughout development. For paternal DNA to participate in mitosis in the embryo, it must first undergo a transition to a histone-packaged state. Despite these differences, both maternal and paternal chromosomes must undergo mitosis at the same time if the zygote is to successfully divide. Although it is known that the egg cell contributes essential proteins that are incorporated into the sperm chromatin to help it reorganize, the importance of paternal proteins in coordinating this process remains poorly understood. Many members of a family of proteins called Heterochromatin Protein 1 (or HP1 for short) have previously been shown to control chromatin organization in plants and animals. In 2012, researchers found that several HP1 proteins are found only in the testes of the fruit fly species Drosophila melanogaster. They predicted that these proteins might help control the reorganization of the paternal chromosomes following fertilization. Levine et al.—including researchers involved in the 2012 study—have now used genetic and cell-based techniques to show that one member of the HP1 family (called HP1E) ensures that the paternal chromosomes are ready for cell division at the same time as the maternal chromosomes. Male flies that are unable to produce this protein do not have any offspring because, while these flies' sperm can fertilize eggs, the resulting zygotes cannot divide as normal. Further experiments revealed that HP1E is not inherited through the chromatin of mature sperm, but instead influences the structure of the chromosomes during the final stages of the development of the sperm cells in the fly testes. This study shows that both maternal and paternal proteins are needed to control how the paternal chromosomes reorganize in fruit fly embryos. Although difficult to discover and decipher, this work re-emphasizes the importance of paternal epigenetic contributions—changes that alter how DNA is read, without changing the DNA sequence itself—for ensuring the viability of resulting offspring. Future work will reveal both the molecular mechanism of this epigenetic transfer of information, as well as why certain Drosophila species are able to naturally overcome the loss of the essential HP1E protein. DOI:http://dx.doi.org/10.7554/eLife.07378.002
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Affiliation(s)
- Mia T Levine
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Helen M Vander Wende
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
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77
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Dritsou V, Topalis P, Windbichler N, Simoni A, Hall A, Lawson D, Hinsley M, Hughes D, Napolioni V, Crucianelli F, Deligianni E, Gasperi G, Gomulski LM, Savini G, Manni M, Scolari F, Malacrida AR, Arcà B, Ribeiro JM, Lombardo F, Saccone G, Salvemini M, Moretti R, Aprea G, Calvitti M, Picciolini M, Papathanos PA, Spaccapelo R, Favia G, Crisanti A, Louis C. A draft genome sequence of an invasive mosquito: an Italian Aedes albopictus. Pathog Glob Health 2015; 109:207-20. [PMID: 26369436 PMCID: PMC4727573 DOI: 10.1179/2047773215y.0000000031] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The draft genome sequence of Italian specimens of the Asian tiger mosquito Aedes (Stegomyia) albopictus (Diptera: Culicidae) was determined using a standard NGS (next generation sequencing) approach. The size of the assembled genome is comparable to that of Aedes aegypti; the two mosquitoes are also similar as far as the high content of repetitive DNA is concerned, most of which is made up of transposable elements. Although, based on BUSCO (Benchmarking Universal Single-Copy Orthologues) analysis, the genome assembly reported here contains more than 99% of protein-coding genes, several of those are expected to be represented in the assembly in a fragmented state. We also present here the annotation of several families of genes (tRNA genes, miRNA genes, the sialome, genes involved in chromatin condensation, sex determination genes, odorant binding proteins and odorant receptors). These analyses confirm that the assembly can be used for the study of the biology of this invasive vector of disease.
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Affiliation(s)
- Vicky Dritsou
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | - Pantelis Topalis
- Institute of Molecular Biology and Biotechnology Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Nikolai Windbichler
- Imperial College London Department of Life Sciences, South Kensington Campus, UK
| | - Alekos Simoni
- Imperial College London Department of Life Sciences, South Kensington Campus, UK
| | - Ann Hall
- Imperial College London Department of Life Sciences, South Kensington Campus, UK
| | - Daniel Lawson
- European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genomes Campus, Cambridge, Cambridgeshire, UK
| | - Malcolm Hinsley
- European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genomes Campus, Cambridge, Cambridgeshire, UK
| | - Daniel Hughes
- European Molecular Biology Laboratory European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genomes Campus, Cambridge, Cambridgeshire, UK
| | - Valerio Napolioni
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | - Francesca Crucianelli
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | - Elena Deligianni
- Institute of Molecular Biology and Biotechnology Foundation for Research and Technology Hellas, Heraklion, Crete, Greece
| | - Giuliano Gasperi
- Department of Biology and Biotechnology University of Pavia, Italy
| | | | - Grazia Savini
- Department of Biology and Biotechnology University of Pavia, Italy
| | - Mosè Manni
- Department of Biology and Biotechnology University of Pavia, Italy
| | | | | | - Bruno Arcà
- Department of Public Health and Infectious Diseases – Division of Parasitology Sapienza University of Rome, Italy
| | - José M. Ribeiro
- National Institute of Allergy and Infectious Diseases Bethesda, MD, USA
| | - Fabrizio Lombardo
- Department of Public Health and Infectious Diseases – Division of Parasitology Sapienza University of Rome, Italy
| | | | - Marco Salvemini
- Department of Biology University of Naples Federico II, Italy
| | - Riccardo Moretti
- ENEA – Italian National Agency for New Technologies Energy and Sustainable Economic Development, CR Casaccia, Rome, Italy
| | - Giuseppe Aprea
- ENEA – Italian National Agency for New Technologies Energy and Sustainable Economic Development, CR Casaccia, Rome, Italy
| | - Maurizio Calvitti
- ENEA – Italian National Agency for New Technologies Energy and Sustainable Economic Development, CR Casaccia, Rome, Italy
| | - Matteo Picciolini
- Polo d'Innovazione di Genomica, Genetica e Biologia (Polo GGB), Loc. S. Andrea delle Fratte, Perugia, Italy
| | | | | | - Guido Favia
- Scuola di Bioscienze e Medicina Veterinaria, University of Camerino, Italy
| | | | - Christos Louis
- Correspondence to: Christos Louis, IMBB-FORTH, N. Plastira 100, Vassilika Vouton, GR-700 13 Heraklion, Crete, Greece.
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Abstract
The development, existence, and functioning of numerous animals and plants depend on their symbiotic interactions with other organisms, mainly microorganisms. In return, the symbionts benefit from safe habitats and nutrient-rich environments provided by their hosts. In these interactions, genetic changes in either of the partners may provide fitness advantages and become subjects to natural selection. Recent findings suggest that epigenetic changes, heritable or within the organism's life time, in either of the partners play significant roles in the establishment of symbiotic relationships. In this review, a variety of epigenetic effects underlying the most common host-symbiont interactions will be examined to determine to what extent these effects are shared in various interactions and how the epigenetic pathways could possibly be manipulated to benefit the interacting symbionts.
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Affiliation(s)
- Sassan Asgari
- Australian Infectious Disease Research Centre, School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
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79
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Hurst GDD, Frost CL. Reproductive parasitism: maternally inherited symbionts in a biparental world. Cold Spring Harb Perspect Biol 2015; 7:a017699. [PMID: 25934011 PMCID: PMC4448626 DOI: 10.1101/cshperspect.a017699] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Most species of insect, and many other plants and animals, carry maternally heritable microorganisms-viruses, bacteria, unicellular eukaryotes, and fungi that pass from a female host to her progeny. Maternal inheritance establishes a correlation between the fitness of symbiont and host female, which can select for the symbiont to contribute to host fitness. Nevertheless, its lack of transmission through male hosts places the symbiont in conflict with biparentally inherited nuclear genes. In this review, we first examine how this conflict is manifest in selection to promote the production and survival of infected female hosts and gametes. We then examine how the distorted population sex ratios that they produce may affect host reproductive ecology, and thus the intensity of other conflicts associated with sexual reproduction. Finally, we examine evolved host responses to symbiont manipulation. We argue that the unusual intensity of symbiont-host conflict generates extreme selection pressures that can drive changes in sex-determination systems, the basic pathway through which males and females are constructed.
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Affiliation(s)
- Gregory D D Hurst
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Crystal L Frost
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
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80
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Zhang YK, Ding XL, Rong X, Hong XY. How do hosts react to endosymbionts? A new insight into the molecular mechanisms underlying the Wolbachia-host association. INSECT MOLECULAR BIOLOGY 2015; 24:1-12. [PMID: 25224730 DOI: 10.1111/imb.12128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Wolbachia is an intracellular bacterium that has aroused intense interest because of its ability to alter the biology of its host in diverse ways. In the two-spotted spider mite, Tetranychus urticae, Wolbachia can induce complex cytoplasmic incompatibility (CI) phenotypes and fitness changes, although little is known about the mechanisms. In the present study, we selected a strain of T. urticae, in which Wolbachia infection was associated with strong CI and enhanced female fecundity, to investigate changes in the transcriptome of T. urticae in Wolbachia-infected vs. uninfected lines. The responses were found to be sex-specific, with the transcription of 251 genes being affected in females and 171 genes being affected in males. Some of the more profoundly affected genes in both sexes were lipocalin genes and genes involved in oxidation reduction, digestion and detoxification. Several of the differentially expressed genes have potential roles in reproduction. Interestingly, unlike certain Wolbachia transinfections in novel hosts, the Wolbachia-host association in the present study showed no clear evidence of host immune priming by Wolbachia, although a few potential immune genes were affected.
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Affiliation(s)
- Y-K Zhang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
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81
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Chen YN, Wu CH, Zheng Y, Li JJ, Wang JL, Wang YF. Knockdown of ATPsyn-b caused larval growth defect and male infertility in Drosophila. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2015; 88:144-154. [PMID: 25336344 DOI: 10.1002/arch.21209] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The ATPsyn-b encoding for subunit b of ATP synthase in Drosophila melanogaster is proposed to act in ATP synthesis and phagocytosis, and has been identified as one of the sperm proteins in both Drosophila and mammals. At present, its details of functions in animal growth and spermatogenesis have not been reported. In this study, we knocked down ATPsyn-b using Drosophila lines expressing inducible hairpin RNAi constructs and Gal4 drivers. Ubiquitous knockdown of ATPsyn-b resulted in growth defects in larval stage as the larvae did not grow bigger than the size of normal second-instar larvae. Knockdown in testes did not interrupt the developmental excursion to viable adult flies, however, these male adults were sterile. Analyses of testes revealed disrupted nuclear bundles during spermatogenesis and abnormal shaping in spermatid elongation. There were no mature sperm in the seminal vesicle of ATPsyn-b knockdown male testes. These findings suggest us that ATPsyn-b acts in growth and male fertility of Drosophila.
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Affiliation(s)
- Ya-Na Chen
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, P. R. China
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82
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Friberg U, Rice WR. Sexually antagonistic zygotic drive: a new form of genetic conflict between the sex chromosomes. Cold Spring Harb Perspect Biol 2015; 7:a017608. [PMID: 25573714 DOI: 10.1101/cshperspect.a017608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Sisters and brothers are completely unrelated with respect to the sex chromosomes they inherit from their heterogametic parent. This has the potential to result in a previously unappreciated form of genetic conflict between the sex chromosomes, called sexually antagonistic zygotic drive (SA-ZD). SA-ZD can arise whenever brothers and sisters compete over limited resources or there is brother-sister mating coupled with inbreeding depression. Although theory predicts that SA-ZD should be common and influence important evolutionary processes, there is little empirical evidence for its existence. Here we discuss the current understanding of SA-ZD, why it would be expected to elude empirical detection when present, and how it relates to other forms of genetic conflict.
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Affiliation(s)
- Urban Friberg
- Department of Evolutionary Biology, Uppsala University, 752 36 Uppsala, Sweden IFM Biology, Linköping University, 581 83 Linköping, Sweden
| | - William R Rice
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California 93111
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83
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Rong X, Zhang YK, Zhang KJ, Hong XY. Identification of Wolbachia-responsive microRNAs in the two-spotted spider mite, Tetranychus urticae. BMC Genomics 2014; 15:1122. [PMID: 25515563 PMCID: PMC4378230 DOI: 10.1186/1471-2164-15-1122] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/09/2014] [Indexed: 01/05/2023] Open
Abstract
Background The two-spotted spider mite, Tetranychus urticae, is infected with Wolbachia, which have the ability to manipulate host reproduction and fitness. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in many biological processes such as development, reproduction and host-pathogen interactions. Although miRNA was observed to involve in Wolbachia-host interactions in the other insect systems, its roles have not been fully deciphered in the two-spotted spider mite. Results Small RNA libraries of infected and uninfected T. urticae for both sexes (in total four libraries) were constructed. By integrating the mRNA data originated from the same samples, the target genes of the differentially expressed miRNAs were predicted. Then, GO and pathway analyses were performed for the target genes. Comparison of libraries showed that Wolbachia infection significantly regulated 91 miRNAs in females and 20 miRNAs in males, with an overall suppression of miRNAs in Wolbachia-infected libraries. A comparison of the miRNA and mRNA data predicted that the differentially expressed miRNAs negatively regulated 90 mRNAs in females and 9 mRNAs in males. An analysis of target genes showed that Wolbachia-responsive miRNAs regulated genes with function in sphingolipid metabolism, lysosome function, apoptosis and lipid transporting in both sexes, as well as reproduction in females. Conclusion Comparisons of the miRNA and mRNA data can help to identify miRNAs and miRNA target genes involving in Wolbachia-host interactions. The molecular targets identified in this study should be useful in further functional studies. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1122) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Xiao-Yue Hong
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu, China.
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84
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LePage DP, Jernigan KK, Bordenstein SR. The relative importance of DNA methylation and Dnmt2-mediated epigenetic regulation on Wolbachia densities and cytoplasmic incompatibility. PeerJ 2014; 2:e678. [PMID: 25538866 PMCID: PMC4266856 DOI: 10.7717/peerj.678] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/06/2014] [Indexed: 12/30/2022] Open
Abstract
Wolbachia pipientis is a worldwide bacterial parasite of arthropods that infects germline cells and manipulates host reproduction to increase the ratio of infected females, the transmitting sex of the bacteria. The most common reproductive manipulation, cytoplasmic incompatibility (CI), is expressed as embryonic death in crosses between infected males and uninfected females. Specifically, Wolbachia modify developing sperm in the testes by unknown means to cause a post-fertilization disruption of the sperm chromatin that incapacitates the first mitosis of the embryo. As these Wolbachia-induced changes are stable, reversible, and affect the host cell cycle machinery including DNA replication and chromosome segregation, we hypothesized that the host methylation pathway is targeted for modulation during cytoplasmic incompatibility because it accounts for all of these traits. Here we show that infection of the testes is associated with a 55% increase of host DNA methylation in Drosophila melanogaster, but methylation of the paternal genome does not correlate with penetrance of CI. Overexpression and knock out of the Drosophila DNA methyltransferase Dnmt2 neither induces nor increases CI. Instead, overexpression decreases Wolbachia titers in host testes by approximately 17%, leading to a similar reduction in CI levels. Finally, strength of CI induced by several different strains of Wolbachia does not correlate with levels of DNA methylation in the host testes. We conclude that DNA methylation mediated by Drosophila’s only known methyltransferase is not required for the transgenerational sperm modification that causes CI.
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Affiliation(s)
- Daniel P LePage
- Department of Biological Sciences, Vanderbilt University , Nashville, TN , USA
| | - Kristin K Jernigan
- Department of Biological Sciences, Vanderbilt University , Nashville, TN , USA ; Department of Cell and Developmental Biology, Vanderbilt University , Nashville, TN , USA
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University , Nashville, TN , USA ; Department of Pathology, Microbiology and Immunology, Vanderbilt University , Nashville, TN , USA
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85
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Rice WR. An X-linked sex ratio distorter in Drosophila simulans that kills or incapacitates both noncarrier sperm and sons. G3 (BETHESDA, MD.) 2014; 4:1837-48. [PMID: 25081980 PMCID: PMC4199691 DOI: 10.1534/g3.114.013292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 07/23/2014] [Indexed: 11/18/2022]
Abstract
Genomic conflict occurs when a genomic component gains a reproductive advantage at the expense of the organism as a whole. X-linked segregation distorters kill or incapacitate Y-bearing sperm, thereby gaining a transmission advantage but also reducing male fertility and generating a female-biased sex ratio. When some damaged, Y-bearing sperm survive and fertilize eggs, then the segregation distortion phenotype could be expanded by harming or killing sons in the next generation. X-linked son-killers are predicted by theory to be favored by natural selection and evolve when brothers and sisters compete for shared limiting resources and/or when brothers reduce the inclusive fitness of their sisters via sib-mating-a phenomenon called SA-zygotic drive. Here I develop and use a process-of-elimination screen to show that an unclassified X-linked sex ratio distorter (skew) in Drosophila simulans kills or incapacitates noncarrier sperm and also kills a substantial proportion of sons, i.e., it has both a segregation distortion and a SA-zygotic drive phenotype. There are three unique X-linked segregation distorters known to occur in D. simulans named Winters, Durham, and Paris. Autosomal-dominant suppressors of Winters (Nmy) and Durham (Tmy) failed to suppress skew. A Y-linked suppressor of Paris, however, did suppress skew, and a recombination test failed to detect recombinants between these two sex ratio distorters, indicating that they are tightly linked and plausibly identical or allelic. Son-killing may be an important yet unrecognized component of other X-linked segregation distorters.
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Affiliation(s)
- William R Rice
- Department of Ecology, Evolution & Marine Biology, University of California, Santa Barbara, California 93106
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86
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Sicard M, Bouchon D, Ceyrac L, Raimond R, Thierry M, Le Clec'h W, Marcadé I, Caubet Y, Grève P. Bidirectional cytoplasmic incompatibility caused by Wolbachia in the terrestrial isopod Porcellio dilatatus. J Invertebr Pathol 2014; 121:28-36. [PMID: 24984056 DOI: 10.1016/j.jip.2014.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/16/2014] [Accepted: 06/19/2014] [Indexed: 11/18/2022]
Abstract
In the terrestrial isopod species Porcellio dilatatus, unidirectional Cytoplasmic Incompatibility (CI) between two morphs (P. d. dilatatus and P. d. petiti) caused by a Wolbachia strain (wPet) infecting the morph P. d. petiti has been previously described by experiments initiated four decades ago. Here, we studied another Wolbachia that has been recently detected in a population of the morph P. d. dilatatus. The MLST markers reveal that this Wolbachia is a new strain called wDil distinct from wPet also belonging to the isopod clade of Wolbachia. Quantifications of both Wolbachia strains in the gonads of the two P. dilatatus morphs revealed that all males exhibit similar Wolbachia titers while the titers in females depend on the Wolbachia strain they host. Crossing experiments showed that both wDil and wPet induced partial unidirectional CI with different intensities. Moreover, these two strains induced bidirectional CI when individuals were both infected with one of the two different Wolbachia strains. This way, we demonstrated that P. dilatatus can be infected by two closely related Wolbachia strains (wDil and wPet), that seem to have different modification-rescue systems.
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Affiliation(s)
- Mathieu Sicard
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Didier Bouchon
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Laura Ceyrac
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Roland Raimond
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Magali Thierry
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Winka Le Clec'h
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Isabelle Marcadé
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Yves Caubet
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France
| | - Pierre Grève
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire EBI Ecologie & Biologie des Interactions, UMR CNRS 7267, Équipe Ecologie, Evolution, Symbiose, Bât. B8-B35, 5, rue Albert Turpin, TSA 51106, F-86073 Poitiers Cedex 9, France.
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87
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Liu C, Wang JL, Zheng Y, Xiong EJ, Li JJ, Yuan LL, Yu XQ, Wang YF. Wolbachia-induced paternal defect in Drosophila is likely by interaction with the juvenile hormone pathway. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 49:49-58. [PMID: 24721205 DOI: 10.1016/j.ibmb.2014.03.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/26/2014] [Accepted: 03/29/2014] [Indexed: 06/03/2023]
Abstract
Wolbachia are endosymbionts that infect many insect species. They can manipulate the host's reproduction to increase their own maternal transmission. Cytoplasmic incompatibility (CI) is one such manipulation, which is expressed as embryonic lethality when Wolbachia-infected males mate with uninfected females. However, matings between males and females carrying the same Wolbachia strain result in viable progeny. The molecular mechanisms of CI are currently not clear. We have previously reported that the gene Juvenile hormone-inducible protein 26 (JhI-26) exhibited the highest upregulation in the 3rd instar larval testes of Drosophila melanogaster when infected by Wolbachia. This is reminiscent of an interaction between Wolbachia and juvenile hormone (JH) pathway in flies. Considering that Jhamt gene encodes JH acid methyltransferase, a key regulatory enzyme of JH biosynthesis, and that methoprene-tolerant (Met) has been regarded as the best JH receptor candidate, we first compared the expression of Jhamt and Met between Wolbachia-infected and uninfected fly testes to investigate whether Wolbachia infection influence the JH signaling pathway. We found that the expressions of Jhamt and Met were significantly increased in the presence of Wolbachia, suggesting an interaction of Wolbachia with the JH signaling pathway. Then, we found that overexpression of JhI-26 in Wolbachia-free transgenic male flies caused paternal-effect lethality that mimics the defects associated with CI. JhI-26 overexpressing males resulted in significantly decrease in hatch rate. Surprisingly, Wolbachia-infected females could rescue the egg hatch. In addition, we showed that overexpression of JhI-26 caused upregulation of the male accessory gland protein (Acp) gene CG10433, but not vice versa. This result suggests that JhI-26 may function at the upstream of CG10433. Likewise, overexpression of CG10433 also resulted in paternal-effect lethality. Both JhI-26 and CG10433 overexpressing males resulted in nuclear division defects in the early embryos. Finally, we found that Wolbachia-infected males decreased the propensity of the mated females to remating, a phenotype also caused by both JhI-26 and CG10433 overexpressing males. Taken together, our results provide a working hypothesis whereby Wolbachia induce paternal defects in Drosophila probably by interaction with the JH pathway via JH response genes JhI-26 and CG10433.
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Affiliation(s)
- Chen Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China
| | - Jia-Lin Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China
| | - Ya Zheng
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China
| | - En-Juan Xiong
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China
| | - Jing-Jing Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China
| | - Lin-Ling Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China
| | - Xiao-Qiang Yu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China; School of Biological Sciences, University of Missouri-Kansas City, MO 64110, USA
| | - Yu-Feng Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan 430079, PR China.
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88
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Perlman SJ, Dowdy NJ, Harris LR, Khalid M, Kelly SE, Hunter MS. Factors affecting the strength of Cardinium-induced cytoplasmic incompatibility in the parasitic wasp Encarsia pergandiella (Hymenoptera: Aphelinidae). MICROBIAL ECOLOGY 2014; 67:671-678. [PMID: 24402369 DOI: 10.1007/s00248-013-0359-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 12/19/2013] [Indexed: 06/03/2023]
Abstract
Bacteria that cause cytoplasmic incompatibility (CI) are among the most common maternally transmitted parasites of insects. In CI, uninfected females produce few or no offspring when they mate with infected males and, as a result, are often at a reproductive disadvantage relative to infected females. Two different bacteria are known to cause CI, Wolbachia and Cardinium. CI Cardinium was discovered more recently and has been little studied. Here, factors that could influence the reduction in reproductive output in a CI cross, or CI "strength," were explored in the parasitic wasp Encarsia pergandiella. Cardinium in this wasp exhibits variable CI strength. Experiments tested the effect of male age, male size, male host species, Cardinium density, and male development time on CI strength. We found a striking effect of male development time, with males that took longer to develop exhibiting stronger CI when mated to uninfected females. Male age had little effect; although in one experiment, the oldest males exhibited stronger CI. Male size, host species, and bacterial density had no effect on the strength of CI. Identifying the factors that control CI are crucial for understanding the dynamics of infection, as well as the success of strategies that aim to use CI microbes to control insect pests and disease vectors.
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Affiliation(s)
- Steve J Perlman
- Department of Biology, University of Victoria, Victoria, British Columbia, V8P 5C2, Canada,
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89
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Ma WJ, Vavre F, Beukeboom LW. Manipulation of arthropod sex determination by endosymbionts: diversity and molecular mechanisms. Sex Dev 2013; 8:59-73. [PMID: 24355929 DOI: 10.1159/000357024] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Arthropods exhibit a large variety of sex determination systems both at the chromosomal and molecular level. Male heterogamety, female heterogamety, and haplodiploidy occur frequently, but partially different genes are involved. Endosymbionts, such as Wolbachia, Cardinium,Rickettsia, and Spiroplasma, can manipulate host reproduction and sex determination. Four major reproductive manipulation types are distinguished: cytoplasmic incompatibility, thelytokous parthenogenesis, male killing, and feminization. In this review, the effects of these manipulation types and how they interfere with arthropod sex determination in terms of host developmental timing, alteration of sex determination, and modification of sexual differentiation pathways are summarized. Transitions between different manipulation types occur frequently which suggests that they are based on similar molecular processes. It is also discussed how mechanisms of reproductive manipulation and host sex determination can be informative on each other, with a special focus on haplodiploidy. Future directions on how the study of endosymbiotic manipulation of host reproduction can be key to further studies of arthropod sex determination are shown.
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Affiliation(s)
- W-J Ma
- Evolutionary Genetics, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
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90
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Rainey SM, Shah P, Kohl A, Dietrich I. Understanding the Wolbachia-mediated inhibition of arboviruses in mosquitoes: progress and challenges. J Gen Virol 2013; 95:517-530. [PMID: 24343914 DOI: 10.1099/vir.0.057422-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Arthropod-borne viruses (arboviruses) pose a considerable threat to human and animal health, yet effective control measures have proven difficult to implement, and novel means of controlling their replication in arthropod vectors, such as mosquitoes, are urgently required. One of the most exciting approaches to emerge from research on arthropods is the use of the endosymbiotic intracellular bacterium Wolbachia to control arbovirus transmission from mosquito to vertebrate. These α-proteobacteria propagate through insects, in part through modulation of host reproduction, thus ensuring spread through species and maintenance in nature. Since it was discovered that Wolbachia endosymbiosis inhibits insect virus replication in Drosophila species, these bacteria have also been shown to inhibit arbovirus replication and spread in mosquitoes. Importantly, it is not clear how these antiviral effects are mediated. This review will summarize recent work and discuss determinants of antiviral effectiveness that may differ between individual Wolbachia/vector/arbovirus interactions. We will also discuss the application of this approach to field settings and the associated risks.
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Affiliation(s)
- Stephanie M Rainey
- MRC - University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow G11 5JR, UK
| | - Pranav Shah
- MRC - University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow G11 5JR, UK
| | - Alain Kohl
- MRC - University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow G11 5JR, UK
| | - Isabelle Dietrich
- MRC - University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow G11 5JR, UK
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91
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Pinto SB, Stainton K, Harris S, Kambris Z, Sutton ER, Bonsall MB, Parkhill J, Sinkins SP. Transcriptional regulation of Culex pipiens mosquitoes by Wolbachia influences cytoplasmic incompatibility. PLoS Pathog 2013; 9:e1003647. [PMID: 24204251 PMCID: PMC3814344 DOI: 10.1371/journal.ppat.1003647] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 08/06/2013] [Indexed: 11/23/2022] Open
Abstract
Cytoplasmic incompatibility (CI) induced by the endosymbiont Wolbachia pipientis causes complex patterns of crossing sterility between populations of the Culex pipiens group of mosquitoes. The molecular basis of the phenotype is yet to be defined. In order to investigate what host changes may underlie CI at the molecular level, we examined the transcription of a homolog of the Drosophila melanogaster gene grauzone that encodes a zinc finger protein and acts as a regulator of female meiosis, in which mutations can cause sterility. Upregulation was observed in Wolbachia-infected C. pipiens group individuals relative to Wolbachia-cured lines and the level of upregulation differed between lines that were reproductively incompatible. Knockdown analysis of this gene using RNAi showed an effect on hatch rates in a Wolbachia infected Culex molestus line. Furthermore, in later stages of development an effect on developmental progression in CI embryos occurs in bidirectionally incompatible crosses. The genome of a wPip Wolbachia strain variant from Culex molestus was sequenced and compared with the genome of a wPip variant with which it was incompatible. Three genes in inserted or deleted regions were newly identified in the C. molestus wPip genome, one of which is a transcriptional regulator labelled wtrM. When this gene was transfected into adult Culex mosquitoes, upregulation of the grauzone homolog was observed. These data suggest that Wolbachia-mediated regulation of host gene expression is a component of the mechanism of cytoplasmic incompatibility. Wolbachia are maternally inherited bacteria that manipulate invertebrate reproduction. Cytoplasmic incompatibility is embryo death that occurs when males carrying Wolbachia mate with females that do not, or that carry a different Wolbachia variant; its mechanism is poorly understood. In Culex mosquitoes, in the presence of Wolbachia a gene related to a Drosophila melanogaster gene, grauzone, which has been shown to act as a regulator of the meiotic cell cycle, showed an elevated level of expression. When lower levels of expression were achieved through RNA interference, embryo hatch rates were affected and the stage of development at which embryo death occurs was altered. To find Wolbachia genes that influence cytoplasmic incompatibility, we compared the genomes of two variants of Wolbachia from Culex that produce cytoplasmic incompatibility with one another. Although most segments of these genomes were very similar, one newly identified gene is predicted to be a regulator of gene transcription. We cloned this gene into a plasmid, expressed it in adult mosquitoes and found higher levels of expression of the Culex grauzone homolog. This suggests that the Wolbachia transcriptional regulator may play an important role in manipulating the host in order to induce cytoplasmic incompatibility.
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Affiliation(s)
- Sofia B. Pinto
- Peter Medawar Building for Pathogen Research and Nuffield Department of Medicine (NDM), University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kirsty Stainton
- Peter Medawar Building for Pathogen Research and Nuffield Department of Medicine (NDM), University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Simon Harris
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Zakaria Kambris
- Peter Medawar Building for Pathogen Research and Nuffield Department of Medicine (NDM), University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Elizabeth R. Sutton
- Peter Medawar Building for Pathogen Research and Nuffield Department of Medicine (NDM), University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - Julian Parkhill
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Steven P. Sinkins
- Peter Medawar Building for Pathogen Research and Nuffield Department of Medicine (NDM), University of Oxford, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- * E-mail:
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92
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Bull JJ, Turelli M. Wolbachia versus dengue: Evolutionary forecasts. EVOLUTION MEDICINE AND PUBLIC HEALTH 2013; 2013:197-207. [PMID: 24481199 PMCID: PMC3847891 DOI: 10.1093/emph/eot018] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel form of biological control is being applied to the dengue virus. The agent is the maternally transmitted bacterium Wolbachia, naturally absent from the main dengue vector, the mosquito Aedes aegypti. Three Wolbachia-based control strategies have been proposed. One is suppression of mosquito populations by large-scale releases of males incompatible with native females; this intervention requires ongoing releases. The other interventions transform wild mosquito populations with Wolbachia that spread via the frequency-dependent fitness advantage of Wolbachia-infected females; those interventions potentially require just a single, local release for area-wide disease control. One of these latter strategies uses Wolbachia that shortens mosquito life, indirectly preventing viral maturation/transmission. The other strategy uses Wolbachia that block viral transmission. All interventions can be undermined by viral, bacterial or mosquito evolution; viral virulence in humans may also evolve. We examine existing theory, experiments and comparative evidence to motivate predictions about evolutionary outcomes. (i) The life-shortening strategy seems the most likely to be thwarted by evolution. (ii) Mosquito suppression has a reasonable chance of working locally, at least in the short term, but long-term success over large areas is challenging. (iii) Dengue blocking faces strong selection for viral resistance but may well persist indefinitely at some level. Virulence evolution is not mathematically predictable, but comparative data provide no precedent for Wolbachia increasing dengue virulence. On balance, our analysis suggests that the considerable possible benefits of these technologies outweigh the known negatives, but the actual risk is largely unknown.
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Affiliation(s)
- James J Bull
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA; Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX 78712, USA; Department of Evolution and Ecology, University of California, Davis, CA 95616, USA; Center for Population Biology, University of California, Davis, CA 95616, USA
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93
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Beckmann JF, Fallon AM. Detection of the Wolbachia protein WPIP0282 in mosquito spermathecae: implications for cytoplasmic incompatibility. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:867-78. [PMID: 23856508 PMCID: PMC3839623 DOI: 10.1016/j.ibmb.2013.07.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/24/2013] [Accepted: 07/04/2013] [Indexed: 05/25/2023]
Abstract
Cytoplasmic incompatibility (CI) is a conditional sterility induced by the bacterium Wolbachia pipientis that infects reproductive tissues in many arthropods. Although CI provides a potential tool to control insect vectors of arthropod-borne diseases, the molecular basis for CI induction is unknown. We hypothesized that a Wolbachia-encoded, CI-inducing factor would be enriched in sperm recovered from spermathecae of female mosquitoes. Using SDS-PAGE and mass spectrometry, we detected peptides from the 56 kDa hypothetical protein, encoded by wPip_0282, associated with sperm transferred to females by Wolbachia infected males. We also detected peptides from the same protein in Wolbachia infected ovaries. Homologs of wPip_0282 and the co-transcribed downstream gene, wPip_0283, occur as multiple divergent copies in genomes of CI-inducing strains of Wolbachia. The operon is located in a genomic context that includes mobile genetic elements. The absence of wPip_0282 and wPip_0283 homologs from genomes of Wolbachia in filarial nematodes, as well as other members of the Rickettsiales, suggests a role as a candidate CI effector.
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Affiliation(s)
- John F Beckmann
- Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA.
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94
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Wolbachia: Can we save lives with a great pandemic? Trends Parasitol 2013; 29:385-93. [PMID: 23845310 DOI: 10.1016/j.pt.2013.06.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/07/2013] [Accepted: 06/10/2013] [Indexed: 11/21/2022]
Abstract
Wolbachia pipientis is the most common bacterial infection in the animal world and wields a vast influence on invertebrate reproduction, sex determination, speciation, and behavior worldwide. These avenues of research have made seminal gains, including the latest use of Wolbachia to alter mosquito populations and a strengthened focus on using anti-Wolbachia therapies against filarial nematode infections. This work is further bolstered by a more refined knowledge of Wolbachia biology spanning mechanisms to relevance. Here we tally the most up-to-date knowledge in the field and review the immense implications that this global infection has for the basic and applied life sciences.
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95
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Ye YH, Woolfit M, Huttley GA, Rancès E, Caragata EP, Popovici J, O'Neill SL, McGraw EA. Infection with a Virulent Strain of Wolbachia Disrupts Genome Wide-Patterns of Cytosine Methylation in the Mosquito Aedes aegypti. PLoS One 2013; 8:e66482. [PMID: 23840485 PMCID: PMC3686743 DOI: 10.1371/journal.pone.0066482] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 05/07/2013] [Indexed: 11/24/2022] Open
Abstract
Background Cytosine methylation is one of several reversible epigenetic modifications of DNA that allow a greater flexibility in the relationship between genotype and phenotype. Methylation in the simplest models dampens gene expression by modifying regions of DNA critical for transcription factor binding. The capacity to methylate DNA is variable in the insects due to diverse histories of gene loss and duplication of DNA methylases. Mosquitoes like Drosophila melanogaster possess only a single methylase, DNMT2. Description Here we characterise the methylome of the mosquito Aedes aegypti and examine its relationship to transcription and test the effects of infection with a virulent strain of the endosymbiont Wolbachia on the stability of methylation patterns. Conclusion We see that methylation in the A. aegypti genome is associated with reduced transcription and is most common in the promoters of genes relating to regulation of transcription and metabolism. Similar gene classes are also methylated in aphids and honeybees, suggesting either conservation or convergence of methylation patterns. In addition to this evidence of evolutionary stability, we also show that infection with the virulent wMelPop Wolbachia strain induces additional methylation and demethylation events in the genome. While most of these changes seem random with respect to gene function and have no detected effect on transcription, there does appear to be enrichment of genes associated with membrane function. Given that Wolbachia lives within a membrane-bound vacuole of host origin and retains a large number of genes for transporting host amino acids, inorganic ions and ATP despite a severely reduced genome, these changes might represent an evolved strategy for manipulating the host environments for its own gain. Testing for a direct link between these methylation changes and expression, however, will require study across a broader range of developmental stages and tissues with methods that detect splice variants.
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Affiliation(s)
- Yixin H. Ye
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Megan Woolfit
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Gavin A. Huttley
- The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Edwige Rancès
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Eric P. Caragata
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Jean Popovici
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Scott L. O'Neill
- School of Biological Sciences, Monash University, Melbourne, Australia
| | - Elizabeth A. McGraw
- School of Biological Sciences, Monash University, Melbourne, Australia
- * E-mail:
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96
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Beckmann JF, Markowski TW, Witthuhn BA, Fallon AM. Detection of the Wolbachia-encoded DNA binding protein, HU beta, in mosquito gonads. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:272-279. [PMID: 23287400 PMCID: PMC3578164 DOI: 10.1016/j.ibmb.2012.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 12/14/2012] [Accepted: 12/18/2012] [Indexed: 05/31/2023]
Abstract
Wolbachia are obligate intracellular bacteria that cause cytoplasmic incompatibility in mosquitoes. In an incompatible cross, eggs of uninfected females fail to hatch when fertilized by sperm from infected males. We used polyacrylamide gel electrophoresis and tandem mass spectrometry to identify Wolbachia proteins in infected mosquito gonads. These included surface proteins with masses of 25 and 18 kDa and the DNA binding protein, HU beta. Using reverse transcriptase polymerase chain reaction, we showed that the HU gene is transcribed in Wolbachia-infected Culex pipiens and Aedes albopictus mosquitoes. We sequenced HU genes from four Wolbachia strains and compared deduced protein sequences with additional homologs from the databases. Among the Rickettsiales, Wolbachia HU has distinct N- and C-terminal basic/acidic amino acid motifs as well as a pair of conserved, cysteine residues.
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Affiliation(s)
- John F Beckmann
- Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA.
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97
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Mousson L, Zouache K, Arias-Goeta C, Raquin V, Mavingui P, Failloux AB. The native Wolbachia symbionts limit transmission of dengue virus in Aedes albopictus. PLoS Negl Trop Dis 2012; 6:e1989. [PMID: 23301109 PMCID: PMC3531523 DOI: 10.1371/journal.pntd.0001989] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 11/16/2012] [Indexed: 01/10/2023] Open
Abstract
Background The chikungunya (CHIK) outbreak that struck La Reunion Island in 2005 was preceded by few human cases of Dengue (DEN), but which surprisingly did not lead to an epidemic as might have been expected in a non-immune population. Both arboviral diseases are transmitted to humans by two main mosquito species, Aedes aegypti and Aedes albopictus. In the absence of the former, Ae. albopictus was the only species responsible for viral transmission on La Reunion Island. This mosquito is naturally super-infected with two Wolbachia strains, wAlbA and wAlbB. While Wolbachia does not affect replication of CHIK virus (CHIKV) in Ae. albopictus, a similar effect was not observed with DEN virus (DENV). Methods/Principal Findings To understand the weak vectorial status of Ae. albopictus towards DENV, we used experimental oral infections of mosquitoes from La Reunion Island to characterize the impact of Wolbachia on DENV infection. Viral loads and Wolbachia densities were measured by quantitative PCR in different organs of Ae. albopictus where DENV replication takes place after ingestion. We found that: (i) Wolbachia does not affect viral replication, (ii) Wolbachia restricts viral density in salivary glands, and (iii) Wolbachia limits transmission of DENV, as infectious viral particles were only detected in the saliva of Wolbachia-uninfected Ae. albopictus, 14 days after the infectious blood-meal. Conclusions We show that Wolbachia does not affect the replication of DENV in Ae. albopictus. However, Wolbachia is able to reduce viral infection of salivary glands and limit transmission, suggesting a role of Wolbachia in naturally restricting the transmission of DENV in Ae. albopictus from La Reunion Island. The extension of this conclusion to other Ae. albopictus populations should be investigated. Aedes albopictus is an invasive species that is expanding its natural range of geographic distribution. While it was previously considered a secondary vector of different arboviruses, this mosquito species is involved in the most recent outbreaks of chikungunya but contributes weakly to dengue outbreaks. Ae. albopictus naturally carries two strains of the bacterium Wolbachia, wAlbA and wAlbB. Present in 20% of insect species, Wolbachia is an obligate intracellular symbiont mainly transmitted through females. When inoculated into some mosquito hosts, Wolbachia is able to shorten the adult life span and to block arbovirus transmission. We have previously shown that Wolbachia is not capable of limiting chikungunya replication in the mosquito vector. In this study, we show that the native Wolbachia is able to limit dengue transmission by restricting the delivery of infectious viral particles from the mosquito saliva when biting. Therefore, our results might explain the low vector competence of Ae. albopictus for dengue, and thus its weak contribution as an epidemic dengue vector.
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Affiliation(s)
- Laurence Mousson
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
| | - Karima Zouache
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
| | - Camilo Arias-Goeta
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
| | - Vincent Raquin
- UMR CNRS 5557, USC INRA 1193, VetAgro Sup, Ecologie Microbienne, Université de Lyon, Villeurbanne, France
| | - Patrick Mavingui
- UMR CNRS 5557, USC INRA 1193, VetAgro Sup, Ecologie Microbienne, Université de Lyon, Villeurbanne, France
| | - Anna-Bella Failloux
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
- * E-mail:
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98
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Xue X, Li SJ, Ahmed MZ, De Barro PJ, Ren SX, Qiu BL. Inactivation of Wolbachia reveals its biological roles in whitefly host. PLoS One 2012; 7:e48148. [PMID: 23144739 PMCID: PMC3483251 DOI: 10.1371/journal.pone.0048148] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 09/20/2012] [Indexed: 11/19/2022] Open
Abstract
Background The whitefly Bemisia tabaci is cryptic species complex composed of numerous species. Individual species from the complex harbor a diversity of bacterial endosymbionts including Wolbachia. However, while Wolbachia is known to have a number of different roles, its role in B. tabaci is unclear. Here, the antibiotic rifampicin is used to selectively eliminate Wolbachia from B. tabaci so as to enable its roles in whitefly development and reproduction to be explored. The indirect effects of Wolbachia elimination on the biology of Encarsia bimaculata, a dominant parasitoid of B. tabaci in South China, were also investigated. Methodology/Principal Finding qRT-PCR and FISH were used to show that after 48 h exposure to 1.0 mg/ml rifampicin, Wolbachia was completely inactivated from B. tabaci Mediterranean (MED) without any significant impact on either the primary symbiont, Portiera aleyrodidarum or any of the other secondary endosymbionts present. For B. tabaci MED, Wolbachia was shown to be associated with decreased juvenile development time, increased likelihood that nymphs completed development, increased adult life span and increased percentage of female progeny. Inactivation was associated with a significant decrease in the body size of the 4th instar which leads us to speculate as to whether Wolbachia may have a nutrient supplementation role. The reduction in nymph body size has consequences for its parasitoid, E. bimaculata. The elimination of Wolbachia lead to a marked increase in the proportion of parasitoid eggs that completed their development, but the reduced size of the whitefly host was also associated with a significant reduction in the size of the emerging parasitoid adult and this was in turn associated with a marked reduction in adult parasitoid longevity. Conclusions/Significance Wolbachia increases the fitness of the whitefly host and provides some protection against parasitization. These observations add to our understanding of the roles played by bacterial endosymbionts.
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Affiliation(s)
- Xia Xue
- Department of Entomology, South China Agricultural University, Guangzhou, China
| | - Shao-Jian Li
- Department of Entomology, South China Agricultural University, Guangzhou, China
| | - Muhammad Z. Ahmed
- Department of Entomology, South China Agricultural University, Guangzhou, China
- Department of Genetics, University of Pretoria, Pretoria, South Africa
| | | | - Shun-Xiang Ren
- Department of Entomology, South China Agricultural University, Guangzhou, China
- * E-mail: (B-LQ); (S-XR)
| | - Bao-Li Qiu
- Department of Entomology, South China Agricultural University, Guangzhou, China
- * E-mail: (B-LQ); (S-XR)
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99
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Brennan LJ, Haukedal JA, Earle JC, Keddie B, Harris HL. Disruption of redox homeostasis leads to oxidative DNA damage in spermatocytes of Wolbachia-infected Drosophila simulans. INSECT MOLECULAR BIOLOGY 2012; 21:510-520. [PMID: 22831171 DOI: 10.1111/j.1365-2583.2012.01155.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Molecular interactions between symbiotic bacteria and their animal hosts are, as yet, poorly understood. The most widespread bacterial endosymbiont, Wolbachia pipientis, occurs in high density in testes of infected Drosophila simulans and causes cytoplasmic incompatibility (CI), a form of male-derived zygotic lethality. Wolbachia grow and divide within host vacuoles that generate reactive oxygen species (ROS), which in turn stimulate the up-regulation of antioxidant enzymes. These enzymes appear to protect the host from ROS-mediated damage, as there is no obvious fitness cost to Drosophila carrying Wolbachia infections. We have now determined that DNA from Wolbachia-infected mosquito Aedes albopictus (Aa23) cells shows a higher amount of the base 8-oxo-deoxyguanosine, a marker of oxidative DNA damage, than DNA from uninfected cells, and that Wolbachia infection in D. simulans is associated with an increase in DNA strand breaks in meiotic spermatocytes. Feeding exogenous antioxidants to male and female D. simulans dramatically increased Wolbachia numbers with no obvious effects on host fitness. These results suggest that ROS-induced DNA damage in sperm nuclei may contribute to the modification characteristic of CI expression in Wolbachia-infected males and that Wolbachia density is sensitive to redox balance in these flies.
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Affiliation(s)
- L J Brennan
- Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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100
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Swim MM, Kaeding KE, Ferree PM. Impact of a selfish B chromosome on chromatin dynamics and nuclear organization in Nasonia. J Cell Sci 2012; 125:5241-9. [PMID: 22899710 DOI: 10.1242/jcs.113423] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
B chromosomes are centric chromosomal fragments present in thousands of eukaryotic genomes. Because most B chromosomes are non-essential, they can be lost without consequence. In order to persist, however, some B chromosomes can impose strong forms of intra-genomic conflict. An extreme case is the paternal sex ratio (PSR) B chromosome in the jewel wasp Nasonia vitripennis. Transmitted solely via the sperm, PSR 'imprints' the paternal chromatin so that it is destroyed during the first mitosis of the embryo. Owing to the haplo-diploid reproduction of N. vitripennis, PSR-induced loss of the paternal chromatin converts embryos that should become females into PSR-transmitting males. This conversion is key to the persistence of PSR, although the underlying mechanisms are largely unexplored. We assessed how PSR affects the paternal chromatin and then investigated how PSR is transmitted efficiently at the cellular level. We found that PSR does not affect progression of the paternal chromatin through the cell cycle but, instead, alters its normal Histone H3 phosphorylation and loading of the Condensin complex. PSR localizes to the outer periphery of the paternal nucleus, a position that we propose is crucial for it to escape from the defective paternal set. In sperm, PSR consistently localizes to the extreme anterior tip of the elongated nucleus, while the normal wasp chromosomes localize broadly across the nucleus. Thus, PSR may alter or bypass normal nuclear organizational processes to achieve its position. These findings provide new insights into how selfish genetic elements can impact chromatin-based processes for their survival.
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Affiliation(s)
- Megan M Swim
- W. M. Keck Science Department of Claremont McKenna, Pitzer and Scripps Colleges, 925 N. Mills Avenue, Claremont, CA 91711, USA
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