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Terradas G, Macias VM, Peterson H, McKeand S, Krawczyk G, Rasgon JL. The Development and Expansion of in vivo Germline Editing Technologies in Arthropods: Receptor-Mediated Ovary Transduction of Cargo (ReMOT Control) and Beyond. Integr Comp Biol 2023; 63:1550-1563. [PMID: 37742320 PMCID: PMC10755176 DOI: 10.1093/icb/icad123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/04/2023] [Accepted: 09/07/2023] [Indexed: 09/26/2023] Open
Abstract
In the past 20 years, sequencing technologies have led to easy access to genomic data from nonmodel organisms in all biological realms. Insect genetic manipulation, however, continues to be a challenge due to various factors, including technical and cost-related issues. Traditional techniques such as microinjection of gene-editing vectors into early stage embryos have been used for arthropod transgenesis and the discovery of Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein (CRISPR-Cas) technologies allowed for targeted mutagenesis and the creation of knockouts or knock-ins in arthropods. Receptor-Mediated Ovary Transduction of Cargo (ReMOT Control) acts as an alternative to embryonic microinjections, which require expensive equipment and extensive hands-on training. ReMOT Control's main advantage is its ease of use coupled with the ability to hypothetically target any vitellogenic species, as injections are administered to the egg-laying adult rather than embryos. After its initial application in the mosquito Aedes aegypti, ReMOT Control has successfully produced mutants not only for mosquitoes but for multiple arthropod species from diverse orders, such as ticks, mites, wasps, beetles, and true bugs, and is being extended to crustaceans, demonstrating the versatility of the technique. In this review, we discuss the current state of ReMOT Control from its proof-of-concept to the advances and challenges in the application across species after 5 years since its development, including novel extensions of the technique such as direct parental (DIPA)-CRISPR.
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Affiliation(s)
- Gerard Terradas
- Department of Entomology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park Pennsylvania, 16802, USA
| | - Vanessa M Macias
- Department of Entomology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park Pennsylvania, 16802, USA
| | - Hillary Peterson
- Department of Entomology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park Pennsylvania, 16802, USA
| | - Sage McKeand
- Department of Entomology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park Pennsylvania, 16802, USA
| | - Grzegorz Krawczyk
- Department of Entomology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park Pennsylvania, 16802, USA
| | - Jason L Rasgon
- Department of Entomology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park Pennsylvania, 16802, USA
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2
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Carabajal Paladino LZ, Wilson R, Tng PYL, Dhokiya V, Keen E, Cuber P, Larner W, Rooney S, Nicholls M, Uglow A, Williams L, Anderson MAE, Basu S, Leftwich PT, Alphey L. Optimizing CRE and PhiC31 mediated recombination in Aedes aegypti. Front Bioeng Biotechnol 2023; 11:1254863. [PMID: 37811374 PMCID: PMC10557486 DOI: 10.3389/fbioe.2023.1254863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/31/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction: Genetic manipulation of Aedes aegypti is key to developing a deeper understanding of this insects' biology, vector-virus interactions and makes future genetic control strategies possible. Despite some advances, this process remains laborious and requires highly skilled researchers and specialist equipment. Methods: Here we present two improved methods for genetic manipulation in this species. Use of transgenic lines which express Cre recombinase and a plasmid-based method for expressing PhiC31 when injected into early embryos. Results: Use of transgenic lines which express Cre recombinase allowed, by simple crossing schemes, germline or somatic recombination of transgenes, which could be utilized for numerous genetic manipulations. PhiC31 integrase based methods for site-specific integration of genetic elements was also improved, by developing a plasmid which expresses PhiC31 when injected into early embryos, eliminating the need to use costly and unstable mRNA as is the current standard. Discussion: Here we have expanded the toolbox for synthetic biology in Ae. aegypti. These methods can be easily transferred into other mosquito and even insect species by identifying appropriate promoter sequences. This advances the ability to manipulate these insects for fundamental studies, and for more applied approaches for pest control.
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3
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Dilani PVD, Dassanayake RS, Tyagi BK, Gunawardene YINS. The impact of transgenesis on mosquito fitness: A review. FRONTIERS IN INSECT SCIENCE 2022; 2:957570. [PMID: 38468772 PMCID: PMC10926467 DOI: 10.3389/finsc.2022.957570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/05/2022] [Indexed: 03/13/2024]
Abstract
Transgenic mosquitoes developed by genetic manipulation, offer a promising strategy for the sustainable and effective control of mosquito-borne diseases. This strategy relies on the mass release of transgenic mosquitoes into the wild, where their transgene is expected to persist in the natural environment, either permanently or transiently, within the mosquito population. In such circumstances, the fitness of transgenic mosquitoes is an important factor in determining their survival in the wild. The impact of transgene expression, insertional mutagenesis, inbreeding depression related to laboratory adaptation, and the hitchhiking effect involved in developing homozygous mosquito lines can all have an effect on the fitness of transgenic mosquitoes. Therefore, real-time estimation of transgene-associated fitness cost is imperative for modeling and planning transgenic mosquito release programs. This can be achieved by directly comparing fitness parameters in individuals homozygous or hemizygous for the transgene and their wild-type counterparts, or by cage invasion experiments to monitor the frequency of the transgenic allele over multiple generations. Recent advancements such as site-specific integration systems and gene drives, provide platforms to address fitness issues in transgenic mosquitoes. More research on the fitness of transgenic individuals is required to develop transgenic mosquitoes with a low fitness cost.
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Affiliation(s)
| | | | - Brij Kishore Tyagi
- Sponsored Research & Industrial Centre, VIT University, Vellore (TN), India
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4
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Vitale M, Leo C, Courty T, Kranjc N, Connolly JB, Morselli G, Bamikole C, Haghighat-Khah RE, Bernardini F, Fuchs S. Comprehensive characterization of a transgene insertion in a highly repetitive, centromeric region of Anopheles mosquitoes. Pathog Glob Health 2022; 117:273-283. [PMID: 35861105 PMCID: PMC10081084 DOI: 10.1080/20477724.2022.2100192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
The availability of the genomic sequence of the malaria mosquito Anopheles gambiae has in recent years sparked the development of transgenic technologies with the potential to be used as novel vector control tools. These technologies rely on genome editing that confer traits able to affect vectorial capacity. This can be achieved by either reducing the mosquito population or by making mosquitoes refractory to the parasite infection. For any genetically modified organism that is regarded for release, molecular characterization of the transgene and flanking sites are essential for their safety assessment and post-release monitoring. Despite great advancements, Whole-Genome Sequencing data are still subject to limitations due to the presence of repetitive and unannotated DNA sequences. Faced with this challenge, we describe a number of techniques that were used to identify the genomic location of a transgene in the male bias mosquito strain Ag(PMB)1 considered for potential field application. While the initial inverse PCR identified the most likely insertion site on Chromosome 3 R 36D, reassessment of the data showed a high repetitiveness in those sequences and multiple genomic locations as potential insertion sites of the transgene. Here we used a combination of DNA sequencing analysis and in-situ hybridization to clearly identify the integration of the transgene in a poorly annotated centromeric region of Chromosome 2 R 19D. This study emphasizes the need for accuracy in sequencing data for the genome of organisms of medical importance such as Anopheles mosquitoes and other tools available that can support genomic locations of transgenes.
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Affiliation(s)
- Matteo Vitale
- Department of Life Sciences, Imperial College London, London, UK
| | - Chiara Leo
- Polo d'Innovazione di Genomica, Genetica, e Biologia, Siena, Italy
| | - Thomas Courty
- Department of Infectious Diseases, King's College London, London, UK
| | - Nace Kranjc
- Department of Life Sciences, Imperial College London, London, UK
| | - John B Connolly
- Department of Life Sciences, Imperial College London, London, UK
| | - Giulia Morselli
- Department of Life Sciences, Imperial College London, London, UK
| | - Christopher Bamikole
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | | | | | - Silke Fuchs
- Department of Life Sciences, Imperial College London, London, UK
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5
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Dong S, Dong Y, Simões ML, Dimopoulos G. Mosquito transgenesis for malaria control. Trends Parasitol 2021; 38:54-66. [PMID: 34483052 DOI: 10.1016/j.pt.2021.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/01/2021] [Accepted: 08/03/2021] [Indexed: 12/14/2022]
Abstract
Malaria is one of the deadliest diseases. Because of the ineffectiveness of current malaria-control methods, several novel mosquito vector-based control strategies have been proposed to supplement existing control strategies. Mosquito transgenesis and gene drive have emerged as promising tools for preventing the spread of malaria by either suppressing mosquito populations by self-destructing mosquitoes or replacing mosquito populations with disease-refractory populations. Here we review the development of mosquito transgenesis and its application for malaria control, highlighting the transgenic expression of antiparasitic effector genes, inactivation of host factor genes, and manipulation of miRNAs and lncRNAs. Overall, from a malaria-control perspective, mosquito transgenesis is not envisioned as a stand-alone approach; rather, its use is proposed as a complement to existing vector-control strategies.
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Affiliation(s)
- Shengzhang Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yuemei Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Maria L Simões
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
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6
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Zhao Z, Tian D, McBride CS. Development of a pan-neuronal genetic driver in Aedes aegypti mosquitoes. CELL REPORTS METHODS 2021; 1:100042. [PMID: 34590074 PMCID: PMC8478256 DOI: 10.1016/j.crmeth.2021.100042] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/10/2021] [Accepted: 06/07/2021] [Indexed: 01/19/2023]
Abstract
The recent development of neurogenetic tools in Aedes aegypti mosquitoes is beginning to shed light on the neural basis of behaviors that make this species a major vector of human disease. However, we still lack a pan-neuronal expression driver-a key tool that provides genetic access to all neurons. Here, we describe our efforts to fill this gap via CRISPR/Cas9-mediated knock-in of reporters to broadly expressed neural genes and report on the generation of two strains, a Syt1:GCaMP6s strain that expresses synaptically localized GCaMP and a brp-T2A-QF2w driver strain that can be used to drive and amplify expression of any effector via the Q binary system. Both manipulations broadly and uniformly label the nervous system with only modest effects on behavior. We expect these strains to facilitate neurobiological research in Ae. aegypti mosquitoes and document both successful and failed manipulations as a roadmap for similar tool development in other non-model species.
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Affiliation(s)
- Zhilei Zhao
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - David Tian
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Carolyn S. McBride
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
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7
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Caragata EP, Dong S, Dong Y, Simões ML, Tikhe CV, Dimopoulos G. Prospects and Pitfalls: Next-Generation Tools to Control Mosquito-Transmitted Disease. Annu Rev Microbiol 2021; 74:455-475. [PMID: 32905752 DOI: 10.1146/annurev-micro-011320-025557] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mosquito-transmitted diseases, including malaria and dengue, are a major threat to human health around the globe, affecting millions each year. A diverse array of next-generation tools has been designed to eliminate mosquito populations or to replace them with mosquitoes that are less capable of transmitting key pathogens. Many of these new approaches have been built on recent advances in CRISPR/Cas9-based genome editing. These initiatives have driven the development of pathogen-resistant lines, new genetics-based sexing methods, and new methods of driving desirable genetic traits into mosquito populations. Many other emerging tools involve microorganisms, including two strategies involving Wolbachia that are achieving great success in the field. At the same time, other mosquito-associated bacteria, fungi, and even viruses represent untapped sources of new mosquitocidal or antipathogen compounds. Although there are still hurdles to be overcome, the prospect that such approaches will reduce the impact of these diseases is highly encouraging.
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Affiliation(s)
- E P Caragata
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA; , , , , ,
| | - S Dong
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA; , , , , ,
| | - Y Dong
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA; , , , , ,
| | - M L Simões
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA; , , , , ,
| | - C V Tikhe
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA; , , , , ,
| | - G Dimopoulos
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA; , , , , ,
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8
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McFarlane M, Laureti M, Levée T, Terry S, Kohl A, Pondeville E. Improved transient silencing of gene expression in the mosquito female Aedes aegypti. INSECT MOLECULAR BIOLOGY 2021; 30:355-365. [PMID: 33715239 DOI: 10.1111/imb.12700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/30/2020] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
Gene silencing using RNA interference (RNAi) has become a widely used genetic technique to study gene function in many organisms. In insects, this technique is often applied through the delivery of dsRNA. In the adult female Aedes aegypti, a main vector of human-infecting arboviruses, efficiency of gene silencing following dsRNA injection varies greatly according to targeted genes. Difficult knockdowns using dsRNA can thus hamper gene function analysis. Here, by analysing silencing of three different genes in female Ae. aegypti (p400, ago2 and E75), we show that gene silencing can indeed be dsRNA sequence dependent but different efficiencies do not correlate with dsRNA length. Our findings suggest that silencing is likely also gene dependent, probably due to gene-specific tissue expression and/or feedback mechanisms. We demonstrate that use of high doses of dsRNA can improve knockdown efficiency, and injection of a transfection reagent along with dsRNA reduces the variability in efficiency between replicates. Finally, we show that gene silencing cannot be achieved using siRNA injection in Ae. aegypti adult females. Overall, this work should help future gene function analyses using RNAi in adult females Ae. aegypti, leading toward a better understanding of physiological and infectious processes.
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Affiliation(s)
- M McFarlane
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - M Laureti
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - T Levée
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - S Terry
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - A Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - E Pondeville
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
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9
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Driesschaert B, Mergan L, Temmerman L. Conditional gene expression in invertebrate animal models. J Genet Genomics 2021; 48:14-31. [PMID: 33814307 DOI: 10.1016/j.jgg.2021.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/11/2020] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
A mechanistic understanding of biology requires appreciating spatiotemporal aspects of gene expression and its functional implications. Conditional expression allows for (ir)reversible switching of genes on or off, with the potential of spatial and/or temporal control. This provides a valuable complement to the more often used constitutive gene (in)activation through mutagenesis, providing tools to answer a wider array of research questions across biological disciplines. Spatial and/or temporal control are granted primarily by (combinations of) specific promoters, temperature regimens, compound addition, or illumination. The use of such genetic tool kits is particularly widespread in invertebrate animal models because they can be applied to study biological processes in short time frames and on large scales, using organisms amenable to easy genetic manipulation. Recent years witnessed an exciting expansion and optimization of such tools, of which we provide a comprehensive overview and discussion regarding their use in invertebrates. The mechanism, applicability, benefits, and drawbacks of each of the systems, as well as further developments to be expected in the foreseeable future, are highlighted.
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Affiliation(s)
- Brecht Driesschaert
- Animal Physiology and Neurobiology, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 59 - Box 2465, B-3000 Leuven, Belgium
| | - Lucas Mergan
- Animal Physiology and Neurobiology, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 59 - Box 2465, B-3000 Leuven, Belgium
| | - Liesbet Temmerman
- Animal Physiology and Neurobiology, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 59 - Box 2465, B-3000 Leuven, Belgium.
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10
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Huynh N, Wang S, King-Jones K. Spatial and temporal control of gene manipulation in Drosophila via drug-activated Cas9 nucleases. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 120:103336. [PMID: 32105778 DOI: 10.1016/j.ibmb.2020.103336] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
Advances in CRISPR/Cas9 have revolutionized molecular biology and greatly facilitated the ability to manipulate gene function through the creation of precisely engineered mutants. We recently reported a collection of modular gateway-compatible Cas9/gRNA Drosophila lines to interfere with gene expression in a tissue-specific manner, including polytene tissues. However, most current in vivo CRISPR/Cas9 tools cannot temporally control the induction of Cas9 or gRNAs via external stimuli such as RU486. A drug-inducible CRISPR/Cas9 system would allow studying genes at later stages where early lethality is an issue. This would be especially useful when combined with tissue-specific expression of Cas9 or gRNAs, allowing for full spatiotemporal control. Here, we present a RU486-inducible version of Cas9 and also show that a Rapamycin-inducible Cas9, previously used in mammalian cell culture, works in Drosophila as well. Both RU486 and rapamycin-inducible Cas9 work in vivo and in Drosophila cell culture. We also present split Cas9 constructs for rapamycin-dependent gene disruption and activation. These approaches establish drug-inducible and thus temporally controlled CRISPR/Cas9 tools for gene disruption and expression in a living model organism. Our CRISPR/Cas9 vector collection can be easily adapted for any tissue and provides higher fidelity compared to RNAi approaches.
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Affiliation(s)
- Nhan Huynh
- Department of Biological Sciences, Faculty of Sciences, University of Alberta, G-502 Biological Sciences Bldg., Edmonton, Alberta, T6G 2E9, Canada
| | - Song Wang
- Department of Biological Sciences, Faculty of Sciences, University of Alberta, G-502 Biological Sciences Bldg., Edmonton, Alberta, T6G 2E9, Canada
| | - Kirst King-Jones
- Department of Biological Sciences, Faculty of Sciences, University of Alberta, G-502 Biological Sciences Bldg., Edmonton, Alberta, T6G 2E9, Canada.
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11
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Ye Z, Liu F, Sun H, Barker M, Pitts RJ, Zwiebel LJ. Heterogeneous expression of the ammonium transporter AgAmt in chemosensory appendages of the malaria vector, Anopheles gambiae. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 120:103360. [PMID: 32126276 PMCID: PMC7161093 DOI: 10.1016/j.ibmb.2020.103360] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 05/03/2023]
Abstract
Ammonia is one of the principal kairomones originating from human and other animal emanations and in that context, plays an essential role in the host-seeking behaviors of the malaria vector mosquito Anopheles gambiae. Nevertheless, despite its importance in directing host-seeking, the mechanisms underlying ammonia detection in the mosquito olfactory system remains largely unknown. In addition to ongoing efforts to identify and characterize the molecular receptors that underlie ammonia sensitivity, previous studies have revealed a prominent role for ammonium transporters (Amt) in modulating antennal and behavioral responses in Drosophila melanogaster and An. gambiae. In the former, localization of DmAmt in antennal sensilla to auxiliary cells surrounding the ammonia sensory neurons led to the hypothesis that its role was to clear excess ammonium ions in the sensillar lymph. In the latter, RT-PCR and heterologous expression have been used to examine the expression and functional characteristics of the An. gambiae ammonium transporter, AgAmt. We now employ advanced transgenic tools to comprehensively examine AgAmt spatial localization across the peripheral chemosensory appendages in larvae and adult female An. gambiae. In the larval antennae, AgAmt appears localized in both neuronal and auxiliary cells. In contrast to D. melanogaster, in the adult antennae, AgAmt-derived signals are observed in both non-neuronal auxiliary cells and in sensory neurons in ammonia-responsive basiconic and coeloconic sensilla. In the maxillary palps, labella, and tarsi, AgAmt appears restricted to sensory neurons. We have also characterized the responses to ammonia of adult antennal coeloconic sensilla and maxillary palp capitate pegs revealing a correlation between sensillar AgAmt expression and ammonia sensitivity. Taken together, these data suggest that AgAmt may play heterogeneous roles in the adult and larval chemosensory apparatus and potentially broad utility as a supra-receptor target in mosquito control.
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Affiliation(s)
- Zi Ye
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Feng Liu
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Huahua Sun
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | | | - R Jason Pitts
- Department of Biology, Baylor University, Waco, TX, 76706, USA
| | - Laurence J Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.
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12
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Shittu M, Steenwinkel T, Koshikawa S, Werner T. The Making of Transgenic Drosophila guttifera. Methods Protoc 2020; 3:E31. [PMID: 32349368 PMCID: PMC7359701 DOI: 10.3390/mps3020031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/25/2020] [Accepted: 04/26/2020] [Indexed: 12/24/2022] Open
Abstract
The complex color patterns on the wings and body of Drosophila guttifera (D. guttifera) are emerging as model systems for studying evolutionary and developmental processes. Studies regarding these processes depend on overexpression and downregulation of developmental genes, which ultimately rely upon an effective transgenic system. Methods describing transgenesis in Drosophila melanogaster (D. melanogaster) have been reported in several studies, but they cannot be applied to D. guttifera due to the low egg production rate and the delicacy of the eggs. In this protocol, we describe extensively a comprehensive method used for generating transgenic D. guttifera. Using the protocol described here, we are able to establish transgenic lines, identifiable by the expression of enhanced green fluorescent protein (EGFP) in the eye disks of D. guttifera larvae. The entire procedure, from injection to screening for transgenic larvae, can be completed in approximately 30 days and should be relatively easy to adapt to other non-model Drosophila species, for which no white-eyed mutants exist.
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Affiliation(s)
- Mujeeb Shittu
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (M.S.); (T.S.)
| | - Tessa Steenwinkel
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (M.S.); (T.S.)
| | - Shigeyuki Koshikawa
- Faculty of Environmental Earth Science, Hokkaido University, N10W5, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
- Graduate School of Environmental Science, Hokkaido University, N10W5, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Thomas Werner
- Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931, USA; (M.S.); (T.S.)
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13
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Matthews BJ, Vosshall LB. How to turn an organism into a model organism in 10 'easy' steps. ACTA ACUST UNITED AC 2020; 223:223/Suppl_1/jeb218198. [PMID: 32034051 DOI: 10.1242/jeb.218198] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Many of the major biological discoveries of the 20th century were made using just six species: Escherichia coli bacteria, Saccharomyces cerevisiae and Schizosaccharomyces pombe yeast, Caenorhabditis elegans nematodes, Drosophila melanogaster flies and Mus musculus mice. Our molecular understanding of the cell division cycle, embryonic development, biological clocks and metabolism were all obtained through genetic analysis using these species. Yet the 'big 6' did not start out as genetic model organisms (hereafter 'model organisms'), so how did they mature into such powerful systems? First, these model organisms are abundant human commensals: they are the bacteria in our gut, the yeast in our beer and bread, the nematodes in our compost pile, the flies in our kitchen and the mice in our walls. Because of this, they are cheaply, easily and rapidly bred in the laboratory and in addition were amenable to genetic analysis. How and why should we add additional species to this roster? We argue that specialist species will reveal new secrets in important areas of biology and that with modern technological innovations like next-generation sequencing and CRISPR-Cas9 genome editing, the time is ripe to move beyond the big 6. In this review, we chart a 10-step path to this goal, using our own experience with the Aedes aegypti mosquito, which we built into a model organism for neurobiology in one decade. Insights into the biology of this deadly disease vector require that we work with the mosquito itself rather than modeling its biology in another species.
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Affiliation(s)
- Benjamin J Matthews
- Department of Zoology, The University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Leslie B Vosshall
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA.,Howard Hughes Medical Institute, New York, NY 10065, USA.,Kavli Neural Systems Institute, New York, NY 10065, USA
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14
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Experimental population modification of the malaria vector mosquito, Anopheles stephensi. PLoS Genet 2019; 15:e1008440. [PMID: 31856182 PMCID: PMC6922335 DOI: 10.1371/journal.pgen.1008440] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 09/19/2019] [Indexed: 12/14/2022] Open
Abstract
Small laboratory cage trials of non-drive and gene-drive strains of the Asian malaria vector mosquito, Anopheles stephensi, were used to investigate release ratios and other strain properties for their impact on transgene spread during simulated population modification. We evaluated the effects of transgenes on survival, male contributions to next-generation populations, female reproductive success and the impact of accumulation of gene drive-resistant genomic target sites resulting from nonhomologous end-joining (NHEJ) mutagenesis during Cas9, guide RNA-mediated cleavage. Experiments with a non-drive, autosomally-linked malaria-resistance gene cassette showed ‘full introduction’ (100% of the insects have at least one copy of the transgene) within 8 weeks (≤ 3 generations) following weekly releases of 10:1 transgenic:wild-type males in an overlapping generation trial design. Male release ratios of 1:1 resulted in cages where mosquitoes with at least one copy of the transgene fluctuated around 50%. In comparison, two of three cages in which the malaria-resistance genes were linked to a gene-drive system in an overlapping generation, single 1:1 release reached full introduction in 6–8 generations with a third cage at ~80% within the same time. Release ratios of 0.1:1 failed to establish the transgenes. A non-overlapping generation, single-release trial of the same gene-drive strain resulted in two of three cages reaching 100% introduction within 6–12 generations following a 1:1 transgenic:wild-type male release. Two of three cages with 0.33:1 transgenic:wild-type male single releases achieved full introduction in 13–16 generations. All populations exhibiting full introduction went extinct within three generations due to a significant load on females having disruptions of both copies of the target gene, kynurenine hydroxylase. While repeated releases of high-ratio (10:1) non-drive constructs could achieve full introduction, results from the 1:1 release ratios across all experimental designs favor the use of gene drive, both for efficiency and anticipated cost of the control programs. The experimental introduction of manipulated genes into insect species has a long history in basic genetics. Recent advances in genome editing technologies have spurred considerable effort to exploit these methodologies to provide genetic solutions to some of the worst medical and agricultural problems caused by insects. Insect population suppression and population modification approaches have been proposed to control transmission of vector-borne diseases, including malaria. We used small cage trials to explore the efficacy of non-drive and gene-drive releases to deliver anti-malarial effector genes to a vector mosquito, Anopheles stephensi. We show that both approaches can work to introduce genes to high percentages, but as expected, the gene-drive approaches were more efficient in that they needed only a single release with a much lower number of released insects. The gene-drive females in our studies exhibited a significant load that resulted in some cage populations going to extinction. Furthermore, the accumulation of drive-resistant target genes prevented full introduction of the transgenes in those cages that did not go extinct. While none of the strains evaluated here are proposed for open release, these laboratory cage trials reveal features that can be used to improve next-generation gene-drive strains for population modification.
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Abstract
Vector control programs based on population reduction by matings with mass-released sterile insects require the release of only male mosquitoes, as the release of females, even if sterile, would increase the number of biting and potentially disease-transmitting individuals. While small-scale releases demonstrated the applicability of sterile males releases to control the yellow fever mosquito Aedes aegypti, large-scale programs for mosquitoes are currently prevented by the lack of efficient sexing systems in any of the vector species.Different approaches of sexing are pursued, including classical genetic and mechanical methods of sex separation. Another strategy is the development of transgenic sexing systems. Such systems already exist in other insect pests. Genome modification tools could be used to apply similar strategies to mosquitoes. Three major tools to modify mosquito genomes are currently used: transposable elements, site-specific recombination systems, and genome editing via TALEN or CRISPR/Cas. All three can serve the purpose of developing sexing systems and vector control strains in mosquitoes in two ways: first, via their use in basic research. A better understanding of mosquito biology, including the sex-determining pathways and the involved genes can greatly facilitate the development of sexing strains. Moreover, basic research can help to identify other regulatory elements and genes potentially useful for the construction of transgenic sexing systems. Second, these genome modification tools can be used to apply the gained knowledge to build and test mosquito sexing strains for vector control.
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Affiliation(s)
- Irina Häcker
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
| | - Marc F Schetelig
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
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Rami A, Raz A, Zakeri S, Dinparast Djadid N. Isolation and identification of Asaia sp. in Anopheles spp. mosquitoes collected from Iranian malaria settings: steps toward applying paratransgenic tools against malaria. Parasit Vectors 2018; 11:367. [PMID: 29950179 PMCID: PMC6022440 DOI: 10.1186/s13071-018-2955-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 06/15/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In recent years, the genus Asaia (Rhodospirillales: Acetobacteraceae) has been isolated from different Anopheles species and presented as a promising tool to combat malaria. This bacterium has unique features such as presence in different organs of mosquitoes (midgut, salivary glands and reproductive organs) of female and male mosquitoes and vertical and horizontal transmission. These specifications lead to the possibility of introducing Asaia as a robust candidate for malaria vector control via paratransgenesis technology. Several studies have been performed on the microbiota of Anopheles mosquitoes (Diptera: Culicidae) in Iran and the Middle East to find a suitable candidate for controlling the malaria based on paratransgenesis approaches. The present study is the first report of isolation, biochemical and molecular characterization of the genus Asaia within five different Anopheles species which originated from different zoogeographical zones in the south, east, and north of Iran. METHODS Mosquitoes originated from field-collected and laboratory-reared colonies of five Anopheles spp. Adult mosquitoes were anesthetized; their midguts were isolated by dissection, followed by grinding the midgut contents which were then cultured in enrichment broth media and later in CaCO3 agar plates separately. Morphological, biochemical and physiological characterization were carried out after the appearance of colonies. For molecular confirmation, selected colonies were cultured, their DNAs were extracted and PCR was performed on the 16S ribosomal RNA gene using specific newly designed primers. RESULTS Morphological, biochemical, physiological and molecular results indicated that all isolates are members of the genus Asaia. CONCLUSIONS Contrary to previous opinions, our findings show that Asaia bacteria are present in both insectary-reared colonies and field-collected mosquitoes and can be isolated by simple and specific methods. Furthermore, with respect to the fact that we isolated Asaia within the different Anopheles specimens from distinct climatic and zoogeographical regions, it is promising and may be concluded that species of this genus can tolerate the complicated environmental conditions of the vector-borne diseases endemic regions. Therefore, it can be considered as a promising target in paratransgenesis and vector control programs. However, we suggest that introducing the new technologies such as next generation sequencing and robust in silico approaches may pave the way to find a unique biomarker for rapid and reliable differentiation of the Asaia species.
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Affiliation(s)
- Abbas Rami
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Abbasali Raz
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Navid Dinparast Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.
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Macias VM, Ohm JR, Rasgon JL. Gene Drive for Mosquito Control: Where Did It Come from and Where Are We Headed? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14091006. [PMID: 28869513 PMCID: PMC5615543 DOI: 10.3390/ijerph14091006] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 02/08/2023]
Abstract
Mosquito-borne pathogens place an enormous burden on human health. The existing toolkit is insufficient to support ongoing vector-control efforts towards meeting disease elimination and eradication goals. The perspective that genetic approaches can potentially add a significant set of tools toward mosquito control is not new, but the recent improvements in site-specific gene editing with CRISPR/Cas9 systems have enhanced our ability to both study mosquito biology using reverse genetics and produce genetics-based tools. Cas9-mediated gene-editing is an efficient and adaptable platform for gene drive strategies, which have advantages over innundative release strategies for introgressing desirable suppression and pathogen-blocking genotypes into wild mosquito populations; until recently, an effective gene drive has been largely out of reach. Many considerations will inform the effective use of new genetic tools, including gene drives. Here we review the lengthy history of genetic advances in mosquito biology and discuss both the impact of efficient site-specific gene editing on vector biology and the resulting potential to deploy new genetic tools for the abatement of mosquito-borne disease.
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Affiliation(s)
- Vanessa M Macias
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
| | - Johanna R Ohm
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
| | - Jason L Rasgon
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
- The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.
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Macias VM, Jimenez AJ, Burini-Kojin B, Pledger D, Jasinskiene N, Phong CH, Chu K, Fazekas A, Martin K, Marinotti O, James AA. nanos-Driven expression of piggyBac transposase induces mobilization of a synthetic autonomous transposon in the malaria vector mosquito, Anopheles stephensi. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 87:81-89. [PMID: 28676355 PMCID: PMC5580807 DOI: 10.1016/j.ibmb.2017.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 06/07/2023]
Abstract
Transposons are a class of selfish DNA elements that can mobilize within a genome. If mobilization is accompanied by an increase in copy number (replicative transposition), the transposon may sweep through a population until it is fixed in all of its interbreeding members. This introgression has been proposed as the basis for drive systems to move genes with desirable phenotypes into target species. One such application would be to use them to move a gene conferring resistance to malaria parasites throughout a population of vector mosquitos. We assessed the feasibility of using the piggyBac transposon as a gene-drive mechanism to distribute anti-malarial transgenes in populations of the malaria vector, Anopheles stephensi. We designed synthetic gene constructs that express the piggyBac transposase in the female germline using the control DNA of the An. stephensi nanos orthologous gene linked to marker genes to monitor inheritance. Two remobilization events were observed with a frequency of one every 23 generations, a rate far below what would be useful to drive anti-pathogen transgenes into wild mosquito populations. We discuss the possibility of optimizing this system and the impetus to do so.
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Affiliation(s)
- Vanessa M Macias
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Alyssa J Jimenez
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Bianca Burini-Kojin
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - David Pledger
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Nijole Jasinskiene
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Celine Hien Phong
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Karen Chu
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Aniko Fazekas
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Kelcie Martin
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Osvaldo Marinotti
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States.
| | - Anthony A James
- Department of Molecular Biology and Biochemistry, University of California, Irvine, 3205 McGaugh Hall, Irvine, CA 92697-3900, United States; Department of Microbiology and Molecular Genetics, B240 Med Sci Bldg., School of Medicine, University of California, Irvine, CA 92697-4025, United States.
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Häcker I, Harrell Ii RA, Eichner G, Pilitt KL, O'Brochta DA, Handler AM, Schetelig MF. Cre/lox-Recombinase-Mediated Cassette Exchange for Reversible Site-Specific Genomic Targeting of the Disease Vector, Aedes aegypti. Sci Rep 2017; 7:43883. [PMID: 28266580 PMCID: PMC5339718 DOI: 10.1038/srep43883] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/30/2017] [Indexed: 12/26/2022] Open
Abstract
Site-specific genome modification (SSM) is an important tool for mosquito functional genomics and comparative gene expression studies, which contribute to a better understanding of mosquito biology and are thus a key to finding new strategies to eliminate vector-borne diseases. Moreover, it allows for the creation of advanced transgenic strains for vector control programs. SSM circumvents the drawbacks of transposon-mediated transgenesis, where random transgene integration into the host genome results in insertional mutagenesis and variable position effects. We applied the Cre/lox recombinase-mediated cassette exchange (RMCE) system to Aedes aegypti, the vector of dengue, chikungunya, and Zika viruses. In this context we created four target site lines for RMCE and evaluated their fitness costs. Cre-RMCE is functional in a two-step mechanism and with good efficiency in Ae. aegypti. The advantages of Cre-RMCE over existing site-specific modification systems for Ae. aegypti, phiC31-RMCE and CRISPR, originate in the preservation of the recombination sites, which 1) allows successive modifications and rapid expansion or adaptation of existing systems by repeated targeting of the same site; and 2) provides reversibility, thus allowing the excision of undesired sequences. Thereby, Cre-RMCE complements existing genomic modification tools, adding flexibility and versatility to vector genome targeting.
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Affiliation(s)
- Irina Häcker
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Robert A Harrell Ii
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, Rockville, Maryland 20850, USA.,Insect Transformation Facility, University of Maryland, College Park, Rockville, Maryland 20850, USA
| | - Gerrit Eichner
- Mathematical Institute, Justus-Liebig-University Giessen, Arndtstrasse 2, 35392 Giessen, Germany
| | - Kristina L Pilitt
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, Rockville, Maryland 20850, USA
| | - David A O'Brochta
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, Rockville, Maryland 20850, USA.,Department of Entomology, University of Maryland, College Park, Rockville, Maryland 20850, USA
| | - Alfred M Handler
- USDA/ARS, Center for Medical, Agricultural and Veterinary Entomology, 1700 SW 23rd Drive, Gainesville, FL 32608, USA
| | - Marc F Schetelig
- Institute for Insect Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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20
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Biological Control Strategies for Mosquito Vectors of Arboviruses. INSECTS 2017; 8:insects8010021. [PMID: 28208639 PMCID: PMC5371949 DOI: 10.3390/insects8010021] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/21/2017] [Indexed: 12/16/2022]
Abstract
Historically, biological control utilizes predatory species and pathogenic microorganisms to reduce the population of mosquitoes as disease vectors. This is particularly important for the control of mosquito-borne arboviruses, which normally do not have specific antiviral therapies available. Although development of resistance is likely, the advantages of biological control are that the resources used are typically biodegradable and ecologically friendly. Over the past decade, the advancement of molecular biology has enabled optimization by the manipulation of genetic materials associated with biological control agents. Two significant advancements are the discovery of cytoplasmic incompatibility induced by Wolbachia bacteria, which has enhanced replacement programs, and the introduction of dominant lethal genes into local mosquito populations through the release of genetically modified mosquitoes. As various arboviruses continue to be significant public health threats, biological control strategies have evolved to be more diverse and become critical tools to reduce the disease burden of arboviruses.
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21
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Gregory M, Alphey L, Morrison NI, Shimeld SM. Insect transformation with piggyBac: getting the number of injections just right. INSECT MOLECULAR BIOLOGY 2016; 25:259-271. [PMID: 27027400 PMCID: PMC4982070 DOI: 10.1111/imb.12220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The insertion of exogenous genetic cargo into insects using transposable elements is a powerful research tool with potential applications in meeting food security and public health challenges facing humanity. piggyBac is the transposable element most commonly utilized for insect germline transformation. The described efficiency of this process is variable in the published literature, and a comprehensive review of transformation efficiency in insects is lacking. This study compared and contrasted all available published data with a comprehensive data set provided by a biotechnology group specializing in insect transformation. Based on analysis of these data, with particular focus on the more complete observational data from the biotechnology group, we designed a decision tool to aid researchers' decision-making when using piggyBac to transform insects by microinjection. A combination of statistical techniques was used to define appropriate summary statistics of piggyBac transformation efficiency by species and insect order. Publication bias was assessed by comparing the data sets. The bias was assessed using strategies co-opted from the medical literature. The work culminated in building the Goldilocks decision tool, a Markov-Chain Monte-Carlo simulation operated via a graphical interface and providing guidance on best practice for those seeking to transform insects using piggyBac.
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Affiliation(s)
- M Gregory
- Department of Zoology, University of Oxford, Oxford, UK
- Oxitec Ltd, Abingdon, UK
| | - L Alphey
- Department of Zoology, University of Oxford, Oxford, UK
- Oxitec Ltd, Abingdon, UK
- The Pirbright Institute, Pirbright, Surrey, UK
| | | | - S M Shimeld
- Department of Zoology, University of Oxford, Oxford, UK
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22
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Abstract
The fields of molecular genetics, biotechnology and synthetic biology are demanding ever more sophisticated molecular tools for programmed precise modification of cell genomic DNA and other DNA sequences. This review presents the current state of knowledge and development of one important group of DNA-modifying enzymes, the site-specific recombinases (SSRs). SSRs are Nature's 'molecular machines' for cut-and-paste editing of DNA molecules by inserting, deleting or inverting precisely defined DNA segments. We survey the SSRs that have been put to use, and the types of applications for which they are suitable. We also discuss problems associated with uses of SSRs, how these problems can be minimized, and how recombinases are being re-engineered for improved performance and novel applications.
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23
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Merrick C, Wardrope C, Paget J, Colloms S, Rosser S. Rapid Optimization of Engineered Metabolic Pathways with Serine Integrase Recombinational Assembly (SIRA). Methods Enzymol 2016; 575:285-317. [DOI: 10.1016/bs.mie.2016.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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24
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Leftwich PT, Bolton M, Chapman T. Evolutionary biology and genetic techniques for insect control. Evol Appl 2016; 9:212-30. [PMID: 27087849 PMCID: PMC4780389 DOI: 10.1111/eva.12280] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/25/2015] [Indexed: 01/15/2023] Open
Abstract
The requirement to develop new techniques for insect control that minimize negative environmental impacts has never been more pressing. Here we discuss population suppression and population replacement technologies. These include sterile insect technique, genetic elimination methods such as the release of insects carrying a dominant lethal (RIDL), and gene driving mechanisms offered by intracellular bacteria and homing endonucleases. We also review the potential of newer or underutilized methods such as reproductive interference, CRISPR technology, RNA interference (RNAi), and genetic underdominance. We focus on understanding principles and potential effectiveness from the perspective of evolutionary biology. This offers useful insights into mechanisms through which potential problems may be minimized, in much the same way that an understanding of how resistance evolves is key to slowing the spread of antibiotic and insecticide resistance. We conclude that there is much to gain from applying principles from the study of resistance in these other scenarios - specifically, the adoption of combinatorial approaches to minimize the spread of resistance evolution. We conclude by discussing the focused use of GM for insect pest control in the context of modern conservation planning under land-sparing scenarios.
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Affiliation(s)
- Philip T. Leftwich
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichUK
| | - Michael Bolton
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichUK
| | - Tracey Chapman
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichUK
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25
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Criscione F, O'Brochta DA, Reid W. Genetic technologies for disease vectors. CURRENT OPINION IN INSECT SCIENCE 2015; 10:90-97. [PMID: 29588019 DOI: 10.1016/j.cois.2015.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 06/08/2023]
Abstract
The first genetic technologies for insect vectors of disease were introduced 20 years ago. As of today there are 12 classes of genetic technologies used as functional genomic tools for insect vectors of important diseases. Although the applications of genetic technologies in insect disease vectors have been conducted primarily in mosquitoes, other insect systems could benefit from current technologies. While the various technological platforms are likely to function in diverse arthropods, the delivery of these technologies to cells and tissues of interest is the major technical constraint that limits their widespread adoption. Increased community resources of various types would enhance the adoption of these technologies and potentially eliminate technical limitations.
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Affiliation(s)
- Frank Criscione
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, 9600 Gudelsky Drive, Rockville, MD 20850, United States.
| | - David A O'Brochta
- Institute for Bioscience and Biotechnology Research, Department of Entomology, University of Maryland, College Park, 9600 Gudelsky Drive, Rockville, MD 20850, United States.
| | - William Reid
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, 9600 Gudelsky Drive, Rockville, MD 20850, United States.
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26
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Abstract
Transgenesis is an essential tool to investigate gene function and to introduce desired characters in laboratory organisms. Setting-up transgenesis in non-model organisms is challenging due to the diversity of biological life traits and due to knowledge gaps in genomic information. Some procedures will be broadly applicable to many organisms, and others have to be specifically developed for the target species. Transgenesis in disease vector mosquitoes has existed since the 2000s but has remained limited by the delicate biology of these insects. Here, we report a compilation of the transgenesis tools that we have designed for the malaria vector Anopheles gambiae, including new docking strains, convenient transgenesis plasmids, a puromycin resistance selection marker, mosquitoes expressing cre recombinase, and various reporter lines defining the activity of cloned promoters. This toolbox contributed to rendering transgenesis routine in this species and is now enabling the development of increasingly refined genetic manipulations such as targeted mutagenesis. Some of the reagents and procedures reported here are easily transferable to other nonmodel species, including other disease vector or agricultural pest insects.
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27
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Franz AWE, Balaraman V, Fraser MJ. Disruption of dengue virus transmission by mosquitoes. CURRENT OPINION IN INSECT SCIENCE 2015; 8:88-96. [PMID: 26120563 PMCID: PMC4480767 DOI: 10.1016/j.cois.2014.12.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Current control efforts for mosquito-borne arboviruses focus on mosquito control involving insecticide applications, which are becoming increasingly ineffective and unsustainable in urban areas. Mosquito population replacement is an alternative arbovirus control concept aiming at replacing virus-competent vector populations with laboratory-engineered incompetent vectors. A prerequisite for this strategy is the design of robust anti-pathogen effectors that can ultimately be genetically driven through a wild-type population. Several anti-pathogen effector concepts have been developed that target the RNA genomes of arboviruses such as dengue virus in a highly sequence-specific manner. Design principles are based on long inverted-repeat RNA triggered RNA interference, catalytic hammerhead ribozymes, and trans-splicing Group I Introns that are able to induce apoptosis in virus-infected cells following splicing with target viral RNA.
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Affiliation(s)
- Alexander W E Franz
- Department of Veterinary Pathobiology, 303 Connaway Hall, College of Veterinary Medicine, University of Missouri, Columbia MO, 65211, United States of America
| | - Velmurugan Balaraman
- Department of Veterinary Pathobiology, 303 Connaway Hall, College of Veterinary Medicine, University of Missouri, Columbia MO, 65211, United States of America
| | - Malcolm J Fraser
- Department of Biological Sciences, 218 Galvin Life Science Bldg., University of Notre Dame, South Bend IN, 46617, United States of America
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28
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Haghighat-Khah RE, Scaife S, Martins S, St John O, Matzen KJ, Morrison N, Alphey L. Site-specific cassette exchange systems in the Aedes aegypti mosquito and the Plutella xylostella moth. PLoS One 2015; 10:e0121097. [PMID: 25830287 PMCID: PMC4382291 DOI: 10.1371/journal.pone.0121097] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/09/2015] [Indexed: 12/02/2022] Open
Abstract
Genetically engineered insects are being evaluated as potential tools to decrease the economic and public health burden of mosquitoes and agricultural pest insects. Here we describe a new tool for the reliable and targeted genome manipulation of pest insects for research and field release using recombinase mediated cassette exchange (RMCE) mechanisms. We successfully demonstrated the established ΦC31-RMCE method in the yellow fever mosquito, Aedes aegypti, which is the first report of RMCE in mosquitoes. A new variant of this RMCE system, called iRMCE, combines the ΦC31-att integration system and Cre or FLP-mediated excision to remove extraneous sequences introduced as part of the site-specific integration process. Complete iRMCE was achieved in two important insect pests, Aedes aegypti and the diamondback moth, Plutella xylostella, demonstrating the transferability of the system across a wide phylogenetic range of insect pests.
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Affiliation(s)
- Roya Elaine Haghighat-Khah
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxitec Limited, Oxford, United Kingdom
| | | | - Sara Martins
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxitec Limited, Oxford, United Kingdom
| | - Oliver St John
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxitec Limited, Oxford, United Kingdom
| | | | | | - Luke Alphey
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Oxitec Limited, Oxford, United Kingdom
- * E-mail: (LA); (KJM)
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Kean J, Rainey SM, McFarlane M, Donald CL, Schnettler E, Kohl A, Pondeville E. Fighting Arbovirus Transmission: Natural and Engineered Control of Vector Competence in Aedes Mosquitoes. INSECTS 2015; 6:236-78. [PMID: 26463078 PMCID: PMC4553541 DOI: 10.3390/insects6010236] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/18/2015] [Accepted: 03/10/2015] [Indexed: 01/09/2023]
Abstract
Control of aedine mosquito vectors, either by mosquito population reduction or replacement with refractory mosquitoes, may play an essential role in the fight against arboviral diseases. In this review, we will focus on the development and application of biological approaches, both natural or engineered, to limit mosquito vector competence for arboviruses. The study of mosquito antiviral immunity has led to the identification of a number of host response mechanisms and proteins that are required to control arbovirus replication in mosquitoes, though more factors influencing vector competence are likely to be discovered. We will discuss key aspects of these pathways as targets either for selection of naturally resistant mosquito populations or for mosquito genetic manipulation. Moreover, we will consider the use of endosymbiotic bacteria such as Wolbachia, which in some cases have proven to be remarkably efficient in disrupting arbovirus transmission by mosquitoes, but also the use of naturally occurring insect-specific viruses that may interfere with arboviruses in mosquito vectors. Finally, we will discuss the use of paratransgenesis as well as entomopathogenic fungi, which are also proposed strategies to control vector competence.
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Affiliation(s)
- Joy Kean
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
| | - Stephanie M Rainey
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
| | - Melanie McFarlane
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
| | - Claire L Donald
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
| | - Esther Schnettler
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
| | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
| | - Emilie Pondeville
- MRC-University of Glasgow Centre for Virus Research, Glasgow, G61 1QH, Scotland, UK.
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Silencing of end-joining repair for efficient site-specific gene insertion after TALEN/CRISPR mutagenesis in Aedes aegypti. Proc Natl Acad Sci U S A 2015; 112:4038-43. [PMID: 25775608 DOI: 10.1073/pnas.1502370112] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Conventional control strategies for mosquito-borne pathogens such as malaria and dengue are now being complemented by the development of transgenic mosquito strains reprogrammed to generate beneficial phenotypes such as conditional sterility or pathogen resistance. The widespread success of site-specific nucleases such as transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 in model organisms also suggests that reprogrammable gene drive systems based on these nucleases may be capable of spreading such beneficial phenotypes in wild mosquito populations. Using the mosquito Aedes aegypti, we determined that mutations in the FokI domain used in TALENs to generate obligate heterodimeric complexes substantially and significantly reduce gene editing rates. We found that CRISPR/Cas9-based editing in the mosquito Ae. aegypti is also highly variable, with the majority of guide RNAs unable to generate detectable editing. By first evaluating candidate guide RNAs using a transient embryo assay, we were able to rapidly identify highly effective guide RNAs; focusing germ line-based experiments only on this cohort resulted in consistently high editing rates of 24-90%. Microinjection of double-stranded RNAs targeting ku70 or lig4, both essential components of the end-joining response, increased recombination-based repair in early embryos as determined by plasmid-based reporters. RNAi-based suppression of Ku70 concurrent with embryonic microinjection of site-specific nucleases yielded consistent gene insertion frequencies of 2-3%, similar to traditional transposon- or ΦC31-based integration methods but without the requirement for an initial docking step. These studies should greatly accelerate investigations into mosquito biology, streamline development of transgenic strains for field releases, and simplify the evaluation of novel Cas9-based gene drive systems.
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An efficient strategy for producing a stable, replaceable, highly efficient transgene expression system in silkworm, Bombyx mori. Sci Rep 2015; 5:8802. [PMID: 25739894 DOI: 10.1038/srep08802] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 02/04/2015] [Indexed: 12/16/2022] Open
Abstract
We developed an efficient strategy that combines a method for the post-integration elimination of all transposon sequences, a site-specific recombination system, and an optimized fibroin H-chain expression system to produce a stable, replaceable, highly efficient transgene expression system in the silkworm (Bombyx mori) that overcomes the disadvantages of random insertion and post-integration instability of transposons. Here, we generated four different transgenic silkworm strains, and of one the transgenic strains, designated TS1-RgG2, with up to 16% (w/w) of the target protein in the cocoons, was selected. The subsequent elimination of all the transposon sequences from TS1-RgG2 was completed by the heat-shock-induced expression of the transposase in vivo. The resulting transgenic silkworm strain was designated TS3-g2 and contained only the attP-flanked optimized fibroin H-chain expression cassette in its genome. A phiC31/att-system-based recombinase-mediated cassette exchange (RMCE) method could be used to integrate other genes of interest into the same genome locus between the attP sites in TS3-g2. Controlling for position effects with phiC31-mediated RMCE will also allow the optimization of exogenous protein expression and fine gene function analyses in the silkworm. The strategy developed here is also applicable to other lepidopteran insects, to improve the ecological safety of transgenic strains in biocontrol programs.
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Zhao B, Kokoza VA, Saha TT, Wang S, Roy S, Raikhel AS. Regulation of the gut-specific carboxypeptidase: a study using the binary Gal4/UAS system in the mosquito Aedes aegypti. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 54:1-10. [PMID: 25152428 PMCID: PMC4426967 DOI: 10.1016/j.ibmb.2014.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/31/2014] [Accepted: 08/03/2014] [Indexed: 05/26/2023]
Abstract
Pathogen transmission by mosquitoes is tightly linked to blood feeding which, in turn, is required for egg development. Studies of these processes would greatly benefit from genetic methods, such as the binary Gal4/UAS system. The latter has been well established for model organisms, but its availability is limited for mosquitoes. The objective of this study was to develop the blood-meal-activated, gut-specific Gal4/UAS system for the yellow-fever mosquito Aedes aegypti and utilize it to investigate the regulation of gut-specific gene expression. A 1.1-kb, 5(') upstream region of the carboxypeptidase A (CP) gene was used to genetically engineer the CP-Gal4 driver mosquito line. The CP-Gal4 specifically activated the Enhanced Green Fluorescent Protein (EGFP) reporter only after blood feeding in the gut of the CP-Gal4 > UAS-EGFP female Ae. aegypti. We used this system to study the regulation of CP gene expression. In vitro treatments with either amino acids (AAs) or insulin stimulated expression of the CP-Gal4 > UAS-EGFP transgene; no effect was observed with 20-hydroxyecdysone (20E) treatments. The transgene activation by AAs and insulin was blocked by rapamycin, the inhibitor of the Target-of-Rapamycin (TOR) kinase. RNA interference (RNAi) silence of the insulin receptor (IR) reduced the expression of the CP-Gal4 > UAS-EGFP transgene. Thus, in vitro and in vivo experiments have revealed that insulin and TOR pathways control expression of the digestive enzyme CP. In contrast, 20E, the major regulator of post-blood-meal vitellogenic events in female mosquitoes, has no role in regulating the expression of this gene. This novel CP-Gal4/UAS system permits functional testing of midgut-specific genes that are involved in blood digestion and interaction with pathogens in Ae. aegypti mosquitoes.
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Affiliation(s)
- Bo Zhao
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; Graduate Program in Genetics, Genomics and Bioinformatics, University of California Riverside, Riverside, CA 92521, USA.
| | - Vladimir A Kokoza
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
| | - Tusar T Saha
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
| | - Stephanie Wang
- Honors Undergraduate Program, University of California Riverside, Riverside, CA 92521, USA.
| | - Sourav Roy
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
| | - Alexander S Raikhel
- Department of Entomology, University of California Riverside, Riverside, CA 92521, USA; The Institute for Integrative Genome Biology, University of California Riverside, Riverside, CA 92521, USA.
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Meza JS, Díaz-Fleischer F, Sánchez-Velásquez LR, Zepeda-Cisneros CS, Handler AM, Schetelig MF. Fitness cost implications of PhiC31-mediated site-specific integrations in target-site strains of the Mexican fruit fly, Anastrepha ludens (Diptera: Tephritidae). PLoS One 2014; 9:e109690. [PMID: 25303238 PMCID: PMC4193812 DOI: 10.1371/journal.pone.0109690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/10/2014] [Indexed: 01/14/2023] Open
Abstract
Site-specific recombination technologies are powerful new tools for the manipulation of genomic DNA in insects that can improve transgenesis strategies such as targeting transgene insertions, allowing transgene cassette exchange and DNA mobilization for transgene stabilization. However, understanding the fitness cost implications of these manipulations for transgenic strain applications is critical. In this study independent piggyBac-mediated attP target-sites marked with DsRed were created in several genomic positions in the Mexican fruit fly, Anastrepha ludens. Two of these strains, one having an autosomal (attP_F7) and the other a Y-linked (attP_2-M6y) integration, exhibited fitness parameters (dynamic demography and sexual competitiveness) similar to wild type flies. These strains were thus selected for targeted insertion using, for the first time in mexfly, the phiC31-integrase recombination system to insert an additional EGFP-marked transgene to determine its effect on host strain fitness. Fitness tests showed that the integration event in the int_2-M6y recombinant strain had no significant effect, while the int_F7 recombinant strain exhibited significantly lower fitness relative to the original attP_F7 target-site host strain. These results indicate that while targeted transgene integrations can be achieved without an additional fitness cost, at some genomic positions insertion of additional DNA into a previously integrated transgene can have a significant negative effect. Thus, for targeted transgene insertions fitness costs must be evaluated both previous to and subsequent to new site-specific insertions in the target-site strain.
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Affiliation(s)
- José S. Meza
- Programa Moscafrut, SAGARPA-IICA, Metapa de Domínguez, Chiapas, México
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Xalapa, Veracruz, México
| | - Francisco Díaz-Fleischer
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Xalapa, Veracruz, México
| | - Lázaro R. Sánchez-Velásquez
- Instituto de Biotecnología y Ecología Aplicada (INBIOTECA), Universidad Veracruzana, Xalapa, Veracruz, México
| | | | - Alfred M. Handler
- Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, Florida, United States of America
| | - Marc F. Schetelig
- Center for Medical, Agricultural, and Veterinary Entomology, Agricultural Research Service, U.S. Department of Agriculture, Gainesville, Florida, United States of America
- Justus-Liebig-University Giessen, Institute for Phytopathology and Applied Zoology, Giessen, Germany
- * E-mail:
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34
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Pondeville E, Puchot N, Meredith JM, Lynd A, Vernick KD, Lycett GJ, Eggleston P, Bourgouin C. Efficient ΦC31 integrase-mediated site-specific germline transformation of Anopheles gambiae. Nat Protoc 2014; 9:1698-712. [PMID: 24945385 DOI: 10.1038/nprot.2014.117] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Current transgenic methodology developed for mosquitoes has not been applied widely to the major malaria vector Anopheles gambiae, which has proved more difficult to genetically manipulate than other mosquito species and dipteran insects. In this protocol, we describe ΦC31-mediated site-specific integration of transgenes into the genome of A. gambiae. The ΦC31 system has many advantages over 'classical' transposon-mediated germline transformation systems, because it allows integration of large transgenes at specific, characterized genomic locations. Starting from a general protocol, we have optimized steps from embryo collection to co-injection of transgene-containing plasmid and in vitro-produced ΦC31 integrase mRNA. We also provide tips for screening transgenic larvae. The outlined procedure provides robust transformation in A. gambiae, resulting in homozygous transgenic lines in ∼2-3 months.
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Affiliation(s)
- Emilie Pondeville
- Institut Pasteur, Genetics and Genomics of Insect Vectors, CNRS unit URA3012, Paris, France
| | - Nicolas Puchot
- Institut Pasteur, Genetics and Genomics of Insect Vectors, CNRS unit URA3012, Paris, France
| | - Janet M Meredith
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Kenneth D Vernick
- Institut Pasteur, Genetics and Genomics of Insect Vectors, CNRS unit URA3012, Paris, France
| | - Gareth J Lycett
- 1] Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK. [2]
| | - Paul Eggleston
- 1] Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK. [2]
| | - Catherine Bourgouin
- 1] Institut Pasteur, Genetics and Genomics of Insect Vectors, CNRS unit URA3012, Paris, France. [2]
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Fogg PCM, Colloms S, Rosser S, Stark M, Smith MCM. New applications for phage integrases. J Mol Biol 2014; 426:2703-16. [PMID: 24857859 PMCID: PMC4111918 DOI: 10.1016/j.jmb.2014.05.014] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 05/09/2014] [Accepted: 05/16/2014] [Indexed: 11/28/2022]
Abstract
Within the last 25 years, bacteriophage integrases have rapidly risen to prominence as genetic tools for a wide range of applications from basic cloning to genome engineering. Serine integrases such as that from ϕC31 and its relatives have found an especially wide range of applications within diverse micro-organisms right through to multi-cellular eukaryotes. Here, we review the mechanisms of the two major families of integrases, the tyrosine and serine integrases, and the advantages and disadvantages of each type as they are applied in genome engineering and synthetic biology. In particular, we focus on the new areas of metabolic pathway construction and optimization, biocomputing, heterologous expression and multiplexed assembly techniques. Integrases are versatile and efficient tools that can be used in conjunction with the various extant molecular biology tools to streamline the synthetic biology production line. Phage integrases are site-specific recombinases that mediate controlled and precise DNA integration and excision. The serine integrases, such as ϕC31 integrase, can be used for efficient recombination in heterologous hosts as they use short recombination substrates, they are directional and they do not require host factors. Both serine and tyrosine integrases, such as λ integrase, are versatile tools for DNA cloning and assembly in vivo and in vitro. Controlled expression of orthologous serine integrases and their cognate recombination directionality factors can be used to generate living biocomputers. Serine integrases are increasingly being exploited for synthetic biology applications.
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Affiliation(s)
- Paul C M Fogg
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Sean Colloms
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| | - Susan Rosser
- School of Biological Sciences, University of Edinburgh, King's Building, Edinburgh EH9 3JR, UK
| | - Marshall Stark
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| | - Margaret C M Smith
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
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36
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Franz AWE, Sanchez-Vargas I, Raban RR, Black WC, James AA, Olson KE. Fitness impact and stability of a transgene conferring resistance to dengue-2 virus following introgression into a genetically diverse Aedes aegypti strain. PLoS Negl Trop Dis 2014; 8:e2833. [PMID: 24810399 PMCID: PMC4014415 DOI: 10.1371/journal.pntd.0002833] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 03/17/2014] [Indexed: 01/11/2023] Open
Abstract
In 2006, we reported a mariner (Mos1)-transformed Aedes aegypti line, Carb77, which was highly resistant to dengue-2 virus (DENV2). Carb77 mosquitoes expressed a DENV2-specific inverted-repeat (IR) RNA in midgut epithelial cells after ingesting an infectious bloodmeal. The IR-RNA formed double-stranded DENV2-derived RNA, initiating an intracellular antiviral RNA interference (RNAi) response. However, Carb77 mosquitoes stopped expressing the IR-RNA after 17 generations in culture and lost their DENV2-refractory phenotype. In the current study, we generated new transgenic lines having the identical transgene as Carb77. One of these lines, Carb109M, has been genetically stable and refractory to DENV2 for >33 generations. Southern blot analysis identified two transgene integration sites in Carb109M. Northern blot analysis detected abundant, transient expression of the IR-RNA 24 h after a bloodmeal. Carb109M mosquitoes were refractory to different DENV2 genotypes but not to other DENV serotypes. To further test fitness and stability, we introgressed the Carb109M transgene into a genetically diverse laboratory strain (GDLS) by backcrossing for five generations and selecting individuals expressing the transgene's EGFP marker in each generation. Comparison of transgene stability in replicate backcross 5 (BC5) lines versus BC1 control lines demonstrated that backcrossing dramatically increased transgene stability. We subjected six BC5 lines to five generations of selection based on EGFP marker expression to increase the frequency of the transgene prior to final family selection. Comparison of the observed transgene frequencies in the six replicate lines relative to expectations from Fisher's selection model demonstrated lingering fitness costs associated with either the transgene or linked deleterious genes. Although minimal fitness loss (relative to GDLS) was manifest in the final family selection stage, we were able to select homozygotes for the transgene in one family, Carb109M/GDLS.BC5.HZ. This family has been genetically stable and DENV2 refractory for multiple generations. Carb109M/GDLS.BC5.HZ represents an important line for testing proof-of-principle vector population replacement. Expression of a DENV2 sequence-derived IR RNA in the mosquito midgut initiates an antiviral intracellular RNAi response that efficiently blocks DENV2 infection and profoundly impairs vector competence for that virus in Aedes aegypti. DENV2-specific IR RNA expression in the Carb109M strain has maintained the RNAi-based, refractory phenotype for 33 generations in laboratory culture. The two transgene integration sites were stable after multiple generations and following introgression into a genetically-diverse (GDLS) Ae. aegypti population. Introgression of the transgene into the GDLS genetic background changed GDLS from a DENV2 susceptible phenotype to a DENV2 refractory phenotype. The DENV2 refractory homozygous line, Carb109M/GDLS.BC5.HZ, exhibits (relative to GDLS) minimal fitness loss associated with the transgene. This line could be a potential candidate for proof-of-principle field studies.
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Affiliation(s)
- Alexander W. E. Franz
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri, United States of America
| | - Irma Sanchez-Vargas
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Robyn R. Raban
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - William C. Black
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Anthony A. James
- Departments of Microbiology and Molecular Genetics and Molecular Biology and Biochemistry, University of California, Irvine, California, United States of America
| | - Ken E. Olson
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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37
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Affiliation(s)
- Luke Alphey
- Oxitec Limited, Milton Park, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Nina Alphey
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
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38
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Aryan A, Myles KM, Adelman ZN. Targeted genome editing in Aedes aegypti using TALENs. Methods 2014; 69:38-45. [PMID: 24556554 DOI: 10.1016/j.ymeth.2014.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/24/2014] [Accepted: 02/06/2014] [Indexed: 01/06/2023] Open
Abstract
The Culicine mosquito, Aedes aegypti, is both a major vector of arthropod-borne viruses (arboviruses) and a genetic model organism for arbovirus transmission. TALE nucleases (TALENs), a group of artificial enzymes capable of generating site-specific DNA lesions, consist of a non-specific FokI endonuclease cleavage domain fused to an engineered DNA binding domain specific to a target site. While TALENs have become an important tool for targeted gene disruption in a variety of organisms, application to the mosquito genome is a new approach. We recently described the use of TALENs to perform heritable genetic disruptions in A. aegypti. Here, we provide detailed methods that will allow other research laboratories to capitalize on the potential of this technology for understanding mosquito gene function. We describe target site selection, transient embryo-based assays to rapidly assess TALEN activity, embryonic microinjection and downstream screening steps to identify target site mutations.
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Affiliation(s)
- Azadeh Aryan
- Fralin Life Science Institute, Dept. of Entomology, Virginia Tech, Blacksburg, VA 20461, United States
| | - Kevin M Myles
- Fralin Life Science Institute, Dept. of Entomology, Virginia Tech, Blacksburg, VA 20461, United States
| | - Zach N Adelman
- Fralin Life Science Institute, Dept. of Entomology, Virginia Tech, Blacksburg, VA 20461, United States.
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McArthur CC, Meredith JM, Eggleston P. Transgenic Anopheles gambiae expressing an antimalarial peptide suffer no significant fitness cost. PLoS One 2014; 9:e88625. [PMID: 24516671 PMCID: PMC3916423 DOI: 10.1371/journal.pone.0088625] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 01/10/2014] [Indexed: 01/11/2023] Open
Abstract
Mosquito-borne diseases present some of the greatest health challenges faced by the world today. In many cases, existing control measures are compromised by insecticide resistance, pathogen tolerance to drugs and the lack of effective vaccines. In light of these difficulties, new genetic tools for disease control programmes, based on the deployment of genetically modified mosquitoes, are seen as having great promise. Transgenic strains may be used to control disease transmission either by suppressing vector populations or by replacing susceptible with refractory genotypes. In practice, the fitness of the transgenic strain relative to natural mosquitoes will be a critical determinant of success. We previously described a transgenic strain of Anopheles gambiae expressing the Vida3 peptide into the female midgut following a blood-meal, which exhibited significant protection against malaria parasites. Here, we investigated the fitness of this strain relative to non-transgenic controls through comparisons of various life history traits. Experiments were designed, as far as possible, to equalize genetic backgrounds and heterogeneity such that fitness comparisons focussed on the presence and expression of the transgene cassette. We also employed reciprocal crosses to identify any fitness disturbance associated with inheritance of the transgene from either the male or female parent. We found no evidence that the presence or expression of the effector transgene or associated fluorescence markers caused any significant fitness cost in relation to larval mortality, pupal sex ratio, fecundity, hatch rate or longevity of blood-fed females. In fact, fecundity was increased in transgenic strains. We did, however, observe some fitness disturbances associated with the route of inheritance of the transgene. Maternal inheritance delayed male pupation whilst paternal inheritance increased adult longevity for both males and unfed females. Overall, in comparison to controls, there was no evidence of significant fitness costs associated with the presence or expression of transgenes in this strain.
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Affiliation(s)
- Clare C. McArthur
- Centre for Applied Entomology and Parasitology, Keele University, Keele, Staffordshire, United Kingdom
| | - Janet M. Meredith
- Centre for Applied Entomology and Parasitology, Keele University, Keele, Staffordshire, United Kingdom
| | - Paul Eggleston
- Centre for Applied Entomology and Parasitology, Keele University, Keele, Staffordshire, United Kingdom
- * E-mail:
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40
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Novel Genetic and Molecular Tools for the Investigation and Control of Dengue Virus Transmission by Mosquitoes. CURRENT TROPICAL MEDICINE REPORTS 2014; 1:21-31. [PMID: 24693489 DOI: 10.1007/s40475-013-0007-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Aedes aegypti is the principal vector of dengue virus (DENV) throughout the tropical world. This anthropophilic mosquito species needs to be persistently infected with DENV before it can transmit the virus through its saliva to a new vertebrate host. In the mosquito, DENV is confronted with several innate immune pathways, among which RNA interference is considered the most important. The Ae. aegypti genome project opened the doors for advanced molecular studies on pathogen-vector interactions including genetic manipulation of the vector for basic research and vector control purposes. Thus, Ae. aegypti has become the primary model for studying vector competence for arboviruses at the molecular level. Here, we present recent findings regarding DENV-mosquito interactions, emphasizing how innate immune responses modulate DENV infections in Ae. aegypti. We also describe the latest advancements in genetic manipulation of Ae. aegypti and discuss how this technology can be used to investigate vector transmission of DENV at the molecular level and to control transmission of the virus in the field.
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41
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Long D, Zhao A, Xu L, Lu W, Guo Q, Zhang Y, Xiang Z. In vivo site-specific integration of transgene in silkworm via PhiC31 integrase-mediated cassette exchange. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:997-1008. [PMID: 23974010 DOI: 10.1016/j.ibmb.2013.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/24/2013] [Accepted: 08/07/2013] [Indexed: 06/02/2023]
Abstract
Current techniques for genetic engineering of the silkworm Bombyx mori genome utilize transposable elements, which result in positional effects and insertional mutagenesis through random insertion of exogenous DNA. New methods for introducing transgenes at specific positions are therefore needed to overcome the limitations of transposon-based strategies. Although site-specific recombination systems have proven powerful tools for genome manipulation in many organisms, their use has not yet been well established for the integration of transgenes in the silkworm. We describe a method for integrating target genes at pre-defined chromosomal sites in the silkworm via phiC31/att site-specific recombination system-mediated cassette exchange. Successful recombinase-mediated cassette exchange (RMCE) was observed in the two transgenic target strains with an estimated transformation efficiency of 3.84-7.01%. Our results suggest that RMCE events between chromosomal attP/attP target sites and incoming attB/attB sites were more frequent than those in the reciprocal direction. This is the first report of in vivo RMCE via phiC31 integrase in the silkworm, and thus represents a key step toward establishing genome manipulation technologies in silkworms and other lepidopteran species.
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Affiliation(s)
- Dingpei Long
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, BeiBei, Chongqing 400716, China
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Smith RC, Kizito C, Rasgon JL, Jacobs-Lorena M. Transgenic mosquitoes expressing a phospholipase A(2) gene have a fitness advantage when fed Plasmodium falciparum-infected blood. PLoS One 2013; 8:e76097. [PMID: 24098427 PMCID: PMC3788000 DOI: 10.1371/journal.pone.0076097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 08/20/2013] [Indexed: 11/18/2022] Open
Abstract
Background Genetically modified mosquitoes have been proposed as an alternative strategy to reduce the heavy burden of malaria. In recent years, several proof-of-principle experiments have been performed that validate the idea that mosquitoes can be genetically modified to become refractory to malaria parasite development. Results We have created two transgenic lines of Anophelesstephensi, a natural vector of Plasmodium falciparum, which constitutively secrete a catalytically inactive phospholipase A2 (mPLA2) into the midgut lumen to interfere with Plasmodium ookinete invasion. Our experiments show that both transgenic lines expressing mPLA2 significantly impair the development of rodent malaria parasites, but only one line impairs the development of human malaria parasites. In addition, when fed on malaria-infected blood, mosquitoes from both transgenic lines are more fecund than non-transgenic mosquitoes. Consistent with these observations, cage experiments with mixed populations of transgenic and non-transgenic mosquitoes show that the percentage of transgenic mosquitoes increases when maintained on Plasmodium-infected blood. Conclusions Our results suggest that the expression of an anti-Plasmodium effector gene gives transgenic mosquitoes a fitness advantage when fed malaria-infected blood. These findings have important implications for future applications of transgenic mosquito technology in malaria control.
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Affiliation(s)
- Ryan C. Smith
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Christopher Kizito
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Jason L. Rasgon
- Department of Entomology, Center for Infectious Disease Dynamics and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Marcelo Jacobs-Lorena
- Department of Molecular Microbiology and Immunology, Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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The developmental transcriptome of the mosquito Aedes aegypti, an invasive species and major arbovirus vector. G3-GENES GENOMES GENETICS 2013; 3:1493-509. [PMID: 23833213 PMCID: PMC3755910 DOI: 10.1534/g3.113.006742] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mosquitoes are vectors of a number of important human and animal diseases. The development of novel vector control strategies requires a thorough understanding of mosquito biology. To facilitate this, we used RNA-seq to identify novel genes and provide the first high-resolution view of the transcriptome throughout development and in response to blood feeding in a mosquito vector of human disease, Aedes aegypti, the primary vector for Dengue and yellow fever. We characterized mRNA expression at 34 distinct time points throughout Aedes development, including adult somatic and germline tissues, by using polyA+ RNA-seq. We identify a total of 14,238 novel new transcribed regions corresponding to 12,597 new loci, as well as many novel transcript isoforms of previously annotated genes. Altogether these results increase the annotated fraction of the transcribed genome into long polyA+ RNAs by more than twofold. We also identified a number of patterns of shared gene expression, as well as genes and/or exons expressed sex-specifically or sex-differentially. Expression profiles of small RNAs in ovaries, early embryos, testes, and adult male and female somatic tissues also were determined, resulting in the identification of 38 new Aedes-specific miRNAs, and ~291,000 small RNA new transcribed regions, many of which are likely to be endogenous small-interfering RNAs and Piwi-interacting RNAs. Genes of potential interest for transgene-based vector control strategies also are highlighted. Our data have been incorporated into a user-friendly genome browser located at www.Aedes.caltech.edu, with relevant links to Vectorbase (www.vectorbase.org)
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Paton D, Underhill A, Meredith J, Eggleston P, Tripet F. Contrasted Fitness Costs of Docking and Antibacterial Constructs in the EE and EVida3 Strains Validates Two-Phase Anopheles gambiae Genetic Transformation System. PLoS One 2013; 8:e67364. [PMID: 23840679 PMCID: PMC3694017 DOI: 10.1371/journal.pone.0067364] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/16/2013] [Indexed: 01/25/2023] Open
Abstract
The deployment of transgenic mosquitoes carrying genes for refractoriness to malaria has long been seen as a futuristic scenario riddled with technical difficulties. The integration of anti-malarial effector genes and a gene-drive system into the mosquito genome without affecting mosquito fitness is recognized as critical to the success of this malaria control strategy. Here we conducted detailed fitness studies of two Anopheles gambiae s.s. transgenic lines recently developed using a two-phase targeted genetic transformation system. In replicated cage-invasion experiments, males and females of the EE Phase-1 docking strain and EVida3 Phase-2 strain loaded with an antimicrobial peptide (AMP) expressed upon blood-feeding, were mixed with individuals of a recently-colonized strain of the Mopti chromosomal form. The experimental design enabled us to detect initial strain reproductive success differences, assortative mating and hybrid vigor that may characterize mosquito release situations. In addition, the potential fitness costs of the unloaded Phase-1 and loaded Phase-2 genetic constructs, independent of the strains' original genetic backgrounds, were estimated between the 1(st) instar larvae, pupae and adult stages over 10 generations. The Phase-1 unloaded docking cassette was found to have significantly lower allelic fitness relative to the wild type allele during larval development. However, overall genotypic fitness was comparable to the wild type allele across all stages leading to stable equilibrium in all replicates. In contrast, the Phase-2 construct expressing EVida3 disappeared from all replicates within 10 generations due to lower fitness of hemi- and homozygous larvae, suggesting costly background AMP expression and/or of the DsRed2 marker. This is the first study to effectively partition independent fitness stage-specific determinants in unloaded and loaded transgenic strains of a Phase-1-2 transformation system. Critically, the high fitness of the Phase-1 docking strain makes it the ideal model system for measuring the genetic load of novel candidate anti-malarial molecules in vivo.
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Affiliation(s)
- Doug Paton
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Anne Underhill
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Janet Meredith
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Paul Eggleston
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
- * E-mail:
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Wilke ABB, Scaife S, Alphey L, Marrelli MT. DsRed2 transient expression in Culex quinquefasciatus mosquitoes. Mem Inst Oswaldo Cruz 2013; 108:529-31. [PMID: 23828005 PMCID: PMC3970632 DOI: 10.1590/s0074-02762013000400023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 12/07/2012] [Indexed: 11/21/2022] Open
Abstract
Culex quinquefasciatus mosquitoes have been successfully genetically modified only once, despite the efforts of several laboratories to transform and establish a stable strain. We have developed a transient gene expression method, in Culex, that delivers plasmid DNA directly to the mosquito haemolymph and additional tissues. We were able to express DsRed2 fluorescent protein in adult Cx. quinquefasciatus mosquitoes by injecting plasmids directly into their thorax. The expression of DsRed2 in adult Cx. quinquefasciatus mosquitoes is an important stepping stone to genetic transformation and the potential use of new control strategies and genetic interactions.
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Affiliation(s)
- André Barretto Bruno Wilke
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brasil.
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Wilke ABB, Scaife S, Alphey L, Marrelli MT. DsRed2 transient expression in Culex quinquefasciatus mosquitoes. Mem Inst Oswaldo Cruz 2013; 108. [PMID: 23828005 PMCID: PMC3970632 DOI: 10.1590/0074-0276108042013023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Culex quinquefasciatus mosquitoes have been successfully genetically modified only once, despite the efforts of several laboratories to transform and establish a stable strain. We have developed a transient gene expression method, in Culex, that delivers plasmid DNA directly to the mosquito haemolymph and additional tissues. We were able to express DsRed2 fluorescent protein in adult Cx. quinquefasciatus mosquitoes by injecting plasmids directly into their thorax. The expression of DsRed2 in adult Cx. quinquefasciatus mosquitoes is an important stepping stone to genetic transformation and the potential use of new control strategies and genetic interactions.
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Affiliation(s)
- André Barretto Bruno Wilke
- Departamento de Epidemiologia, Faculdade de Saúde Pública,
Universidade de São Paulo, São Paulo, SP, Brasil,Corresponding author:
| | | | - Luke Alphey
- Oxitec Ltd, Oxford, United Kingdom,Department of Zoology, University of Oxford, Oxford, United
Kingdom
| | - Mauro Toledo Marrelli
- Departamento de Epidemiologia, Faculdade de Saúde Pública,
Universidade de São Paulo, São Paulo, SP, Brasil
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Marinotti O, Jasinskiene N, Fazekas A, Scaife S, Fu G, Mattingly ST, Chow K, Brown DM, Alphey L, James AA. Development of a population suppression strain of the human malaria vector mosquito, Anopheles stephensi. Malar J 2013; 12:142. [PMID: 23622561 PMCID: PMC3648444 DOI: 10.1186/1475-2875-12-142] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 04/19/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Transgenic mosquito strains are being developed to contribute to the control of dengue and malaria transmission. One approach uses genetic manipulation to confer conditional, female-specific dominant lethality phenotypes. Engineering of a female-specific flightless phenotype provides a sexing mechanism essential for male-only mosquito, release approaches that result in population suppression of target vector species. METHODS An approach that uses a female-specific gene promoter and antibiotic-repressible lethal factor to produce a sex-specific flightless phenotype was adapted to the human malaria vector, Anopheles stephensi. Transposon- and site-specific recombination-mediated technologies were used to generate a number of transgenic An. stephensi lines that when combined through mating produced the phenotype of flight-inhibited females and flight-capable males. RESULTS The data shown here demonstrate the successful engineering of a female-specific flightless phenotype in a malaria vector. The flightless phenotype was repressible by the addition of tetracycline to the larval diet. This conditional phenotype allows the rearing of the strains under routine laboratory conditions. The minimal level of tetracycline that rescues the flightless phenotype is higher than that found as an environmental contaminant in circumstances where there is intensive use of antibiotics. CONCLUSIONS These studies support the further development of flightless female technology for applications in malaria control programmes that target the vectors.
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Affiliation(s)
- Osvaldo Marinotti
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
| | - Nijole Jasinskiene
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
| | - Aniko Fazekas
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
| | - Sarah Scaife
- Oxitec Ltd, 71 Milton Park, Abingdon, Oxfordshire, OX14 4RX, UK
| | - Guoliang Fu
- Oxitec Ltd, 71 Milton Park, Abingdon, Oxfordshire, OX14 4RX, UK
| | - Stefanie T Mattingly
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
| | - Karissa Chow
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
| | - David M Brown
- Departments of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, 3205 McGaugh Hall, University of California, Irvine, CA, 92697-3900, USA
| | - Luke Alphey
- Oxitec Ltd, 71 Milton Park, Abingdon, Oxfordshire, OX14 4RX, UK
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Anthony A James
- Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697-3900, USA
- Departments of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, 3205 McGaugh Hall, University of California, Irvine, CA, 92697-3900, USA
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A Functional Comparison of the 3xP3 Promoter by Recombinase-Mediated Cassette Exchange in Drosophila and a Tephritid Fly, Anastrepha suspensa. G3-GENES GENOMES GENETICS 2013; 3:687-693. [PMID: 23550127 PMCID: PMC3618355 DOI: 10.1534/g3.112.005488] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Transposable elements are widely used as vectors for integrating transgenes into the genome of insects. However, the random nature of transposon vector integrations often results in mutations and makes transgene expression subject to variable genomic position effects. This makes reliable quantitative comparisons of different transgenes difficult and development of highly fit transgenic strains laborious. Tools for site-specific transgene targeting are essential for functional genomic comparisons and to develop the most advanced transgenic insect strains for applied use. Here we describe a recombinase-mediated cassette exchange gene targeting system based on Cre/loxP that is highly efficient in Drosophila, and for the first time in a non-drosophilid, the tephritid fly, Anastrepha suspensa This system allowed a comparison of the Drosophila constitutive polyubiquitin promoter and the artificial 3xP3 tissue-specific promoter in the same genomic context within each species, showing that the widely used 3xP3 promoter is apparently nonfunctional in the tephritid fly.
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Lindahl JF, Ståhl K, Chirico J, Boqvist S, Thu HTV, Magnusson U. Circulation of Japanese encephalitis virus in pigs and mosquito vectors within Can Tho city, Vietnam. PLoS Negl Trop Dis 2013; 7:e2153. [PMID: 23593520 PMCID: PMC3617195 DOI: 10.1371/journal.pntd.0002153] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 02/26/2013] [Indexed: 11/18/2022] Open
Abstract
Japanese encephalitis virus (JEV) is a mosquito-borne, zoonotic flavivirus causing encephalitis in humans and reproductive disorder in pigs. JEV is present in large parts of Asia, where urbanization is high. Households within and outside Can Tho city, South Vietnam, were selected to monitor circulation of JEV. A nested RT-PCR was established to detect the presence of JEV in mosquitoes whereas sera from pigs belonging to households within the province were analyzed for the presence of antibodies to JEV. A total of 7885 mosquitoes were collected and divided into 352 pools whereof seven were JEV-positive, six of which were collected within the city. Fragments from four pools clustered with JEV genotype III and three with genotype I. Of the 43 pigs sampled inside the city 100% had JEV antibodies. Our study demonstrates exposure to JEV in pigs, and co-circulation of JEV genotype I and III in mosquitoes within an urban environment in South Vietnam. Thus, although JEV has mainly been considered a rural disease, the potential for transmission in urban areas cannot be ignored.
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Affiliation(s)
- Johanna F. Lindahl
- Department of Clinical Sciences, Division of Reproduction, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Karl Ståhl
- Department of Biomedicine and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jan Chirico
- Department of Virology, Immunology and Parasitology, National Veterinary Institute, National Veterinary Institute, SVA, Uppsala, Sweden
| | - Sofia Boqvist
- Department of Biomedicine and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ho Thi Viet Thu
- Department of Veterinary Medicine, Can Tho University, Can Tho City, Vietnam
| | - Ulf Magnusson
- Department of Clinical Sciences, Division of Reproduction, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Meredith JM, Underhill A, McArthur CC, Eggleston P. Next-generation site-directed transgenesis in the malaria vector mosquito Anopheles gambiae: self-docking strains expressing germline-specific phiC31 integrase. PLoS One 2013; 8:e59264. [PMID: 23516619 PMCID: PMC3596282 DOI: 10.1371/journal.pone.0059264] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 02/13/2013] [Indexed: 01/27/2023] Open
Abstract
Diseases transmitted by mosquitoes have a devastating impact on global health and the situation is complicated due to difficulties with both existing control measures and the impact of climate change. Genetically modified mosquitoes that are refractory to disease transmission are seen as having great potential in the delivery of novel control strategies. The Streptomyces phage phiC31 integrase system has been successfully adapted for site-directed transgene integration in a range of insects, thus overcoming many limitations due to size constraints and random integration associated with transposon-mediated transformation. Using this technology, we previously published the first site-directed transformation of Anopheles gambiae, the principal vector of human malaria. Mosquitoes were initially engineered to incorporate the phiC31 docking site at a defined genomic location. A second phase of genetic modification then achieved site-directed integration of an anti-malarial effector gene. In the current publication we report improved efficiency and utility of the phiC31 integrase system following the generation of Anopheles gambiae self-docking strains. Four independent strains, with docking sites at known locations on three different chromosome arms, were engineered to express integrase under control of the regulatory regions of the nanos gene from Anopheles gambiae. The resulting protein accumulates in the posterior oocyte to provide integrase activity at the site of germline development. Two self-docking strains, exhibiting significantly different levels of integrase expression, were assessed for site-directed transgene integration and found to demonstrate greatly improved survival and efficiency of transformation. In the fight against malaria, it is imperative to establish a broad repertoire of both anti-malarial effector genes and tissue-specific promoters to regulate their expression, enabling those offering maximum effect with minimum fitness cost to be identified. The improved technology we describe here will facilitate comparative studies of effector transgenes, allowing informed choices to be made that potentially lead to transmission blockade.
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Affiliation(s)
- Janet M. Meredith
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Ann Underhill
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Clare C. McArthur
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
| | - Paul Eggleston
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, United Kingdom
- * E-mail:
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