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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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Pham M, Hoffmann HH, Kurtti TJ, Chana R, Garcia-Cruz O, Aliabadi S, Gulia-Nuss M. Validation of a heat-inducible Ixodes scapularis HSP70 promoter and developing a tick-specific 3xP3 promoter sequence in ISE6 cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569248. [PMID: 38076872 PMCID: PMC10705397 DOI: 10.1101/2023.11.29.569248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Ixodes scapularis is an important vector of many pathogens, including the causative agent of Lyme disease, tick-borne encephalitis, and anaplasmosis. The study of gene function in I. scapularis and other ticks has been hampered by the lack of genetic tools, such as an inducible promoter to permit temporal control over transgenes encoding protein or double-stranded RNA expression. Studies of vector-pathogen relationships would also benefit from the capability to activate anti-pathogen genes at different times during pathogen infection and dissemination. We have characterized an intergenic sequence upstream of the heat shock protein 70 (HSP70) gene that can drive Renilla luciferase expression and mCherry fluorescence in the I. scapularis cell line ISE6. In another construct, we replaced the Drosophila melanogaster minimal HSP70 promoter in the synthetic 3xP3 promoter with a minimal portion of the I. scapularis HSP70 promoter and generated an I. scapularis specific 3xP3 (Is3xP3) promoter. Both promoter constructs, IsHSP70 and Is3xP3, allow for heat-inducible expression of mCherry fluorescence in ISE6 cells with an approximately 10-fold increase in the percentage of fluorescent positive cells upon exposure to a 2 h heat shock. These promoters described here will be valuable tools for gene function studies and temporal control of gene expression, including anti-pathogen genes.
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Affiliation(s)
- Michael Pham
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, USA
| | | | | | - Randeep Chana
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, USA
| | - Omar Garcia-Cruz
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, USA
| | - Simindokht Aliabadi
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, USA
| | - Monika Gulia-Nuss
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, USA
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Häcker I, Rehling T, Schlosser H, Mayorga-Ch D, Heilig M, Yan Y, Armbruster PA, Schetelig MF. Improved piggyBac Transformation with Capped Transposase mRNA in Pest Insects. Int J Mol Sci 2023; 24:15155. [PMID: 37894833 PMCID: PMC10606561 DOI: 10.3390/ijms242015155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/29/2023] Open
Abstract
Creating transgenic insects is a key technology in insect genetics and molecular biology. A widely used instrument in insect transgenesis is the piggyBac transposase, resulting in essentially random genomic integrations. In contrast, site-specific recombinases allow the targeted integration of the transgene construct into a specific genomic target site. Both strategies, however, often face limitations due to low transgenesis efficiencies. We aimed to enhance transgenesis efficiencies by utilizing capped mRNA as a source of transposase or recombinase instead of a helper plasmid. A systematic comparison of transgenesis efficiencies in Aedes mosquitoes, as models for hard-to-transform insects, showed that suppling piggyBac transposase as mRNA increased the average transformation efficiency in Aedes aegypti from less than 5% with the plasmid source to about 50% with mRNA. Similar high activity was observed in Ae. albopictus with pBac mRNA. No efficiency differences between plasmid and mRNA were observed in recombination experiments. Furthermore, a hyperactive version of piggyBac transposase delivered as a plasmid did not improve the transformation efficiency in Ae. aegypti or the agricultural pest Drosophila suzukii. We believe that the use of mRNA has strong potential for enhancing piggyBac transformation efficiencies in other mosquitoes and important agricultural pests, such as tephritids.
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Affiliation(s)
- Irina Häcker
- Department of Insect Biotechnology in Plant Protection, Justus Liebig University Giessen, Winchesterstr. 2, 35394 Giessen, Germany (H.S.); (Y.Y.); (M.F.S.)
- Liebig Centre for Agroecology & Climate Impact Research, 35394 Giessen, Germany
| | - Tanja Rehling
- Department of Insect Biotechnology in Plant Protection, Justus Liebig University Giessen, Winchesterstr. 2, 35394 Giessen, Germany (H.S.); (Y.Y.); (M.F.S.)
- Liebig Centre for Agroecology & Climate Impact Research, 35394 Giessen, Germany
| | - Henrik Schlosser
- Department of Insect Biotechnology in Plant Protection, Justus Liebig University Giessen, Winchesterstr. 2, 35394 Giessen, Germany (H.S.); (Y.Y.); (M.F.S.)
| | - Daniela Mayorga-Ch
- Department of Insect Biotechnology in Plant Protection, Justus Liebig University Giessen, Winchesterstr. 2, 35394 Giessen, Germany (H.S.); (Y.Y.); (M.F.S.)
| | - Mara Heilig
- Department of Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057-1229, USA; (M.H.); (P.A.A.)
| | - Ying Yan
- Department of Insect Biotechnology in Plant Protection, Justus Liebig University Giessen, Winchesterstr. 2, 35394 Giessen, Germany (H.S.); (Y.Y.); (M.F.S.)
- Liebig Centre for Agroecology & Climate Impact Research, 35394 Giessen, Germany
| | - Peter A. Armbruster
- Department of Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057-1229, USA; (M.H.); (P.A.A.)
| | - Marc F. Schetelig
- Department of Insect Biotechnology in Plant Protection, Justus Liebig University Giessen, Winchesterstr. 2, 35394 Giessen, Germany (H.S.); (Y.Y.); (M.F.S.)
- Liebig Centre for Agroecology & Climate Impact Research, 35394 Giessen, Germany
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Bui M, Dalla Benetta E, Dong Y, Zhao Y, Yang T, Li M, Antoshechkin IA, Buchman A, Bottino-Rojas V, James AA, Perry MW, Dimopoulos G, Akbari OS. CRISPR mediated transactivation in the human disease vector Aedes aegypti. PLoS Pathog 2023; 19:e1010842. [PMID: 36656895 PMCID: PMC9888728 DOI: 10.1371/journal.ppat.1010842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 01/31/2023] [Accepted: 12/28/2022] [Indexed: 01/20/2023] Open
Abstract
As a major insect vector of multiple arboviruses, Aedes aegypti poses a significant global health and economic burden. A number of genetic engineering tools have been exploited to understand its biology with the goal of reducing its impact. For example, current tools have focused on knocking-down RNA transcripts, inducing loss-of-function mutations, or expressing exogenous DNA. However, methods for transactivating endogenous genes have not been developed. To fill this void, here we developed a CRISPR activation (CRISPRa) system in Ae. aegypti to transactivate target gene expression. Gene expression is activated through pairing a catalytically-inactive ('dead') Cas9 (dCas9) with a highly-active tripartite activator, VP64-p65-Rta (VPR) and synthetic guide RNA (sgRNA) complementary to a user defined target-gene promoter region. As a proof of concept, we demonstrate that engineered Ae. aegypti mosquitoes harboring a binary CRISPRa system can be used to effectively overexpress two developmental genes, even-skipped (eve) and hedgehog (hh), resulting in observable morphological phenotypes. We also used this system to overexpress the positive transcriptional regulator of the Toll immune pathway known as AaRel1, which resulted in a significant suppression of dengue virus serotype 2 (DENV2) titers in the mosquito. This system provides a versatile tool for research pathways not previously possible in Ae. aegypti, such as programmed overexpression of endogenous genes, and may aid in gene characterization studies and the development of innovative vector control tools.
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Affiliation(s)
- Michelle Bui
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Elena Dalla Benetta
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Yuemei Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yunchong Zhao
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Ting Yang
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Ming Li
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Igor A. Antoshechkin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Anna Buchman
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Vanessa Bottino-Rojas
- Department of Microbiology & Molecular Genetics, University of California Irvine, Irvine, California, United States of America
| | - Anthony A. James
- Department of Microbiology & Molecular Genetics, University of California Irvine, Irvine, California, United States of America
- Department of Molecular Biology & Biochemistry, University of California Irvine, Irvine, California, United States of America
| | - Michael W. Perry
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Omar S. Akbari
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, San Diego, California, United States of America
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Bottino-Rojas V, James AA. Use of Insect Promoters in Genetic Engineering to Control Mosquito-Borne Diseases. Biomolecules 2022; 13:biom13010016. [PMID: 36671401 PMCID: PMC9855440 DOI: 10.3390/biom13010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 12/16/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
Mosquito transgenesis and gene-drive technologies provide the basis for developing promising new tools for vector-borne disease prevention by either suppressing wild mosquito populations or reducing their capacity from transmitting pathogens. Many studies of the regulatory DNA and promoters of genes with robust sex-, tissue- and stage-specific expression profiles have supported the development of new tools and strategies that could bring mosquito-borne diseases under control. Although the list of regulatory elements available is significant, only a limited set of those can reliably drive spatial-temporal expression. Here, we review the advances in our ability to express beneficial and other genes in mosquitoes, and highlight the information needed for the development of new mosquito-control and anti-disease strategies.
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Affiliation(s)
- Vanessa Bottino-Rojas
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, USA
| | - Anthony A. James
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
- Correspondence:
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Kojin BB, Jakes E, Biedler JK, Tu Z, Adelman ZN. Partial masculinization of Aedes aegypti females by conditional expression of Nix. PLoS Negl Trop Dis 2022; 16:e0010598. [PMID: 35776760 PMCID: PMC9307153 DOI: 10.1371/journal.pntd.0010598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 07/22/2022] [Accepted: 06/20/2022] [Indexed: 11/18/2022] Open
Abstract
Background
Aedes aegypti, the main vector of dengue, yellow fever, and other arboviruses thrives in tropical and subtropical areas around the globe putting half of the world’s population at risk. Despite aggressive efforts to control the transmission of those viruses, an unacceptable number of cases occur every year, emphasizing the need to develop new control strategies. Proposals for vector control focused on population suppression could offer a feasible alternative method to reduce disease transmission. The induction of extreme male-biased sex ratios has been hypothesized to be able to suppress or collapse a population, with previous experiments showing that stable expression of the male determining factor Nix in A. aegypti is sufficient to convert females into fertile males.
Methodology/Principal findings
Here, we report on the conditional expression of Nix in transgenic A. aegypti under the control of the tetracycline-dependent (Tet-off) system, with the goal of establishing repressible sex distortion. A masculinization phenotype was observed in three of the seven transgenic lines with females exhibiting male-like long maxillary palps and most importantly, the masculinized females were unable to blood feed. Doxycycline treatment of the transgenic lines only partially restored the normal phenotype from the masculinized transgenic lines, while RT-qPCR analysis of early embryos or adults showed no correlation between the level of masculinization and ectopic Nix expression.
Conclusions/Significance
While the conditional expression of Nix produced intersex phenotypes, the level of expression was insufficient to program full conversion. Modifications that increase both the level of activation (no tet) and the level of repression (with tet) will be necessary, as such this study represents one step forward in the development of genetic strategies to control vector-borne diseases via sex ratio distortion.
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Affiliation(s)
- Bianca B. Kojin
- Department of Entomology and Agrilife Research, Texas A&M University, College Station, Texas, United States of America
| | - Emma Jakes
- Department of Entomology and Agrilife Research, Texas A&M University, College Station, Texas, United States of America
| | - James K. Biedler
- Department of Biochemistry and Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Zhijian Tu
- Department of Biochemistry and Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Zach N. Adelman
- Department of Entomology and Agrilife Research, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
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Bottino-Rojas V, Ferreira-Almeida I, Nunes RD, Feng X, Pham TB, Kelsey A, Carballar-Lejarazú R, Gantz V, Oliveira PL, James AA. Beyond the eye: Kynurenine pathway impairment causes midgut homeostasis dysfunction and survival and reproductive costs in blood-feeding mosquitoes. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 142:103720. [PMID: 34999199 PMCID: PMC11055609 DOI: 10.1016/j.ibmb.2022.103720] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Insect ommochrome biosynthesis pathways metabolize tryptophan to generate eye-color pigments and wild-type alleles of pathway genes are useful phenotypic markers in transgenesis studies. Pleiotropic effects of mutations in some genes exert a load on both survival and reproductive success in blood-feeding species. Here, we investigated the challenges imposed on mosquitoes by the increase of tryptophan metabolites resulting from blood meal digestion and the impact of disruptions of the ommochrome biosynthesis pathway. Female mosquitoes with spontaneous and induced mutations in the orthologs of the genes encoding kynurenine hydroxylase in Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus exhibited impaired survival and reproductive phenotypes that varied in type and severity among the species. A compromised midgut permeability barrier function was also observed in An. stephensi. Surprisingly, mutant mosquitoes displayed an increase in microbiota compared to controls that was not accompanied by a general induction of immune genes. Antibiotic treatment rescued some deleterious traits implicating a role for the kynurenine pathway (KP) in midgut homeostasis. Supplemental xanthurenic acid, a KP end-product, rescued lethality and limited microbiota proliferation in Ae. aegypti. These data implicate the KP in the regulation of the host/microbiota interface. These pleiotropic effects on mosquito physiology are important in the development of genetic strategies targeting vector mosquitoes.
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Affiliation(s)
- Vanessa Bottino-Rojas
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, USA
| | - Igor Ferreira-Almeida
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Rodrigo D Nunes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Xuechun Feng
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Thai Binh Pham
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, USA
| | - Adam Kelsey
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, USA
| | | | - Valentino Gantz
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Pedro L Oliveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil.
| | - Anthony A James
- Department of Microbiology & Molecular Genetics, University of California, Irvine, CA, USA; Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, USA.
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Ang JXD, Nevard K, Ireland R, Purusothaman DK, Verkuijl SAN, Shackleford L, Gonzalez E, Anderson MAE, Alphey L. Considerations for homology-based DNA repair in mosquitoes: Impact of sequence heterology and donor template source. PLoS Genet 2022; 18:e1010060. [PMID: 35180218 PMCID: PMC8893643 DOI: 10.1371/journal.pgen.1010060] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 03/03/2022] [Accepted: 01/28/2022] [Indexed: 12/23/2022] Open
Abstract
The increasing prevalence of insecticide resistance and the ongoing global burden of vector-borne diseases have encouraged new efforts in mosquito control. For Aedes aegypti, the most important arboviral vector, integration rates achieved in Cas9-based knock-ins so far have been rather low, highlighting the need to understand gene conversion patterns and other factors that influence homology-directed repair (HDR) events in this species. In this study, we report the effects of sequence mismatches or donor template forms on integration rates. We found that modest sequence differences between construct homology arms [DNA sequence in the donor template which resembles the region flanking the target cut] and genomic target comprising 1.2% nucleotide dissimilarity (heterology) significantly reduced integration rates. While most integrations (59–88%) from plasmid templates were the result of canonical [on target, perfect repair] HDR events, no canonical events were identified from other donor types (i.e. ssDNA, biotinylated ds/ssDNA). Sequencing of the transgene flanking region in 69 individuals with canonical integrations revealed 60% of conversion tracts to be unidirectional and extend up to 220 bp proximal to the break, though in three individuals bidirectional conversion of up to 725 bp was observed. The field of genetic control of mosquito vectors has progressed rapidly in recent years, especially in Cas9-based control systems, due to its robustness to elicit a species-specific and dispersive control of mosquito population. To generate a Cas9-based integration, Cas9 and sgRNA are used to cleave a chromosomal locus while a plasmid DNA donor, containing a genetic cargo flanked by sequences homologous to the chromosomal locus, is supplied as a repair template. This results in the cargo being copied into the genome through HDR. This form of integration, however, is currently one of the major bottlenecks for researchers as it involves a laborious process of microinjecting mosquito embryos and has rather low integration rates. In this study, we assessed the effects of homologous sequence mismatches and various donor template forms (i.e. plasmid, ssDNA, biotinylated ds/ssDNA) on HDR. We found that sequence mismatches and non-plasmid donors reduced the efficiency and integrity of integration, respectively. By analysing the direction and length of homologous sequence that was copied into the genome concurrently with the cargo, we inferred the mechanism responsible for the integrations observed in our study. These findings will be useful to guide future construct designs for optimal HDR rates in mosquitoes.
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Affiliation(s)
| | | | | | | | - Sebald A. N. Verkuijl
- The Pirbright Institute, Pirbright, Woking, United Kingdom
- Mathematical Ecology Research Group, Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | | | | | - Luke Alphey
- The Pirbright Institute, Pirbright, Woking, United Kingdom
- * E-mail: (MAEA); (LA)
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9
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Webster SH, Scott MJ. The Aedes aegypti (Diptera: Culicidae) hsp83 Gene Promoter Drives Strong Ubiquitous DsRed and ZsGreen Marker Expression in Transgenic Mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:2533-2537. [PMID: 34302473 DOI: 10.1093/jme/tjab128] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Indexed: 06/13/2023]
Abstract
Transgenic strains of the mosquito disease vector Aedes aegypti (L.) are being developed for population suppression or modification. Transgenic mosquitoes are identified using fluorescent protein genes. Here we describe DsRed and ZsGreen marker genes driven by the constitutive Ae. aegypti heat shock protein 83 (hsp83) promoter in transgenic mosquitoes. Transgenic larvae and pupae show strong full body expression of the red and green fluorescent proteins. This greatly assists in screening for transgenic individuals while making new or maintaining already established lines. Transient marker gene expression after embryo microinjection was readily visible in developing larvae allowing the separation of individuals that are more likely to produce transgenic offspring. The strongly expressed marker genes developed in this study should facilitate the detection of transgenic Ae. aegypti larvae or pupae in the field.
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Affiliation(s)
- Sophia H Webster
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Maxwell J Scott
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, USA
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10
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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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11
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Liu JG, Qiao L, Zhang JJ, Chen B, He ZB. piggyBac-mediated germline transformation of the malaria mosquito Anopheles sinensis (Diptera: Culicidae). INSECT SCIENCE 2021; 28:1202-1206. [PMID: 32519503 DOI: 10.1111/1744-7917.12836] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 04/23/2020] [Accepted: 05/24/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Jin-Gang Liu
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Liang Qiao
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Jia-Jun Zhang
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Bin Chen
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Zheng-Bo He
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, China
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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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13
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Che LR, He ZB, Liu Y, Yan ZT, Han BZ, Chen XJ, He XF, Zhang JJ, Chen B, Qiao L. Electroporation-mediated nucleic acid delivery during non-embryonic stages for gene-function analysis in Anopheles sinensis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 128:103500. [PMID: 33278627 DOI: 10.1016/j.ibmb.2020.103500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
The delivery of exogenous nucleic acids to eggs or non-embryonic individuals by microinjection is a vital reverse genetics technique used to determine gene function in mosquitoes. However, DNA delivery to eggs is complex and time-consuming, and conventional, non-embryonic-injection techniques may result in unobvious phenotypes caused by insufficient absorption of nucleic acid fragments by cells at target body parts or tissues. In this study, we developed a set of electroporation-mediated non-embryonic microinjections for the delivery of exogenous nucleic acids in Anopheles sinensis. Gene silencing using this method led to down-regulation of target gene expression (AsCPR128) by 77% in targeted body parts, compared with only 10% in non-targeted body parts, thus increasing the defect-phenotype rate in the target area by 5.3-fold, compared with non-shock injected controls. Electroporation-mediated somatic transgenesis resulted in stable phenotypic characteristics of the reporter gene at the shocked body parts during the pupal-adult stages in about 69% of individuals. Furthermore, injecting plasmid DNA near the ovaries of female mosquitoes after a blood meal followed by electric shock produced three germline G1 transgenic lines, with a transformation rate of about 11.1% (calculated from ovulatory G0 females). Among the positive G1 lines, 42%, 40%, and 31% of individuals emitted red fluorescence in the larval stage. When the red fluorescent larvae developed into adults, green fluorescence was emitted from the ovaries of the females upon feeding. These results suggest that electroporation-mediated non-embryonic microinjection can be an efficient, rapid, and simple technique for analyzing gene function in non-model mosquitoes or other small insects.
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Affiliation(s)
- Lin-Rong Che
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Zheng-Bo He
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Yan Liu
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Zhen-Tian Yan
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Bao-Zhu Han
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xiao-Jie Chen
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Xing-Fei He
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Jia-Jun Zhang
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China
| | - Bin Chen
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
| | - Liang Qiao
- Chongqing Key Laboratory of Vector Insects, Institute of Entomology and Molecular Biology, College of Life Sciences, Chongqing Normal University, Chongqing, 401331, China.
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The Antiviral Small-Interfering RNA Pathway Induces Zika Virus Resistance in Transgenic Aedes aegypti. Viruses 2020; 12:v12111231. [PMID: 33142991 PMCID: PMC7692394 DOI: 10.3390/v12111231] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 01/21/2023] Open
Abstract
The resurgence of arbovirus outbreaks across the globe, including the recent Zika virus (ZIKV) epidemic in 2015–2016, emphasizes the need for innovative vector control methods. In this study, we investigated ZIKV susceptibility to transgenic Aedes aegypti engineered to target the virus by means of the antiviral small-interfering RNA (siRNA) pathway. The robustness of antiviral effector expression in transgenic mosquitoes is strongly influenced by the genomic insertion locus and transgene copy number; we therefore used CRISPR/Cas9 to re-target a previously characterized locus (Chr2:321382225) and engineered mosquitoes expressing an inverted repeat (IR) dsRNA against the NS3/4A region of the ZIKV genome. Small RNA analysis revealed that the IR effector triggered the mosquito’s siRNA antiviral pathway in bloodfed females. Nearly complete (90%) inhibition of ZIKV replication was found in vivo in both midguts and carcasses at 7 or 14 days post-infection (dpi). Furthermore, significantly fewer transgenic mosquitoes contained ZIKV in their salivary glands (p = 0.001), which led to a reduction in the number of ZIKV-containing saliva samples as measured by transmission assay. Our work shows that Ae. aegypti innate immunity can be co-opted to engineer mosquitoes resistant to ZIKV.
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15
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Asad M, Munir F, Xu X, Li M, Jiang Y, Chu L, Yang G. Functional characterization of the cis-regulatory region for the vitellogenin gene in Plutella xylostella. INSECT MOLECULAR BIOLOGY 2020; 29:137-147. [PMID: 31850544 DOI: 10.1111/imb.12632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/23/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
The vitellogenin gene promoter (VgP) is an essential cis-regulatory element that plays a significant role in transcription of the vitellogenin (Vg) gene, leading to the production of yolk protein in insects, including lepidopterans. However, the function of VgP is still not clear in Plutella xylostella. Here, we cloned a 5.1 kb DNA fragment of the cis-regulatory region adjacent to the 5' end of the Vg gene of P. xylostella (PxVg). We identified two promoter sites in that 5' upstream sequence of PxVg and performed in vitro analysis of two promoter sequences (PxVgP1, 4.9 kb, and PxVgP2, 2.9 kb) in the embryonic cell line of P. xylostella. PxVgP2 exhibited higher enhanced green fluorescent protein (EGFP) expression, so PxVgP2 was used for in vivo analysis. Strong EGFP fluorescence was observed in adult females and the fat body of females, with low expression in embryos. Our results suggest that PxVgP is an important stage-, tissue- and sex-specific endogenous cis-regulatory element in P. xylostella.
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Affiliation(s)
- M Asad
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
| | - F Munir
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
| | - X Xu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
| | - M Li
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
| | - Y Jiang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
| | - L Chu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
| | - G Yang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- Joint International Research Laboratory of Ecological Pest Control, Ministry of Education, Fuzhou, China
- Key Laboratory of Integrated Pest Management for Fujian-Taiwan Crops, Ministry of Agriculture, Fuzhou, China
- Key Laboratory of Green Pest Control, Fujian Province University, Fuzhou, China
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16
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Antiviral Effectors and Gene Drive Strategies for Mosquito Population Suppression or Replacement to Mitigate Arbovirus Transmission by Aedes aegypti. INSECTS 2020; 11:insects11010052. [PMID: 31940960 PMCID: PMC7023000 DOI: 10.3390/insects11010052] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 12/11/2022]
Abstract
The mosquito vector Aedes aegypti transmits arthropod-borne viruses (arboviruses) of medical importance, including Zika, dengue, and yellow fever viruses. Controlling mosquito populations remains the method of choice to prevent disease transmission. Novel mosquito control strategies based on genetically manipulating mosquitoes are being developed as additional tools to combat arbovirus transmission. Genetic control of mosquitoes includes two basic strategies: population suppression and population replacement. The former aims to eliminate mosquito populations while the latter aims to replace wild populations with engineered, pathogen-resistant mosquitoes. In this review, we outline suppression strategies being applied in the field, as well as current antiviral effector genes that have been characterized and expressed in transgenic Ae. aegypti for population replacement. We discuss cutting-edge gene drive technologies that can be used to enhance the inheritance of effector genes, while highlighting the challenges and opportunities associated with gene drives. Finally, we present currently available models that can estimate mosquito release numbers and time to transgene fixation for several gene drive systems. Based on the recent advances in genetic engineering, we anticipate that antiviral transgenic Ae. aegypti exhibiting gene drive will soon emerge; however, close monitoring in simulated field conditions will be required to demonstrate the efficacy and utility of such transgenic mosquitoes.
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Buchman A, Gamez S, Li M, Antoshechkin I, Li HH, Wang HW, Chen CH, Klein MJ, Duchemin JB, Crowe JE, Paradkar PN, Akbari OS. Broad dengue neutralization in mosquitoes expressing an engineered antibody. PLoS Pathog 2020; 16:e1008103. [PMID: 31945137 PMCID: PMC6964813 DOI: 10.1371/journal.ppat.1008103] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/23/2019] [Indexed: 12/11/2022] Open
Abstract
With dengue virus (DENV) becoming endemic in tropical and subtropical regions worldwide, there is a pressing global demand for effective strategies to control the mosquitoes that spread this disease. Recent advances in genetic engineering technologies have made it possible to create mosquitoes with reduced vector competence, limiting their ability to acquire and transmit pathogens. Here we describe the development of Aedes aegypti mosquitoes synthetically engineered to impede vector competence to DENV. These mosquitoes express a gene encoding an engineered single-chain variable fragment derived from a broadly neutralizing DENV human monoclonal antibody and have significantly reduced viral infection, dissemination, and transmission rates for all four major antigenically distinct DENV serotypes. Importantly, this is the first engineered approach that targets all DENV serotypes, which is crucial for effective disease suppression. These results provide a compelling route for developing effective genetic-based DENV control strategies, which could be extended to curtail other arboviruses.
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Affiliation(s)
- Anna Buchman
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, United States of America
| | - Stephanie Gamez
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, United States of America
| | - Ming Li
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, United States of America
| | - Igor Antoshechkin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States of America
| | - Hsing-Han Li
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Zhunan, Taiwan
| | - Hsin-Wei Wang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Zhunan, Taiwan
| | - Chun-Hong Chen
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Zhunan, Taiwan
| | - Melissa J. Klein
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, VIC, Australia
| | - Jean-Bernard Duchemin
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, VIC, Australia
| | - James E. Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Departments of Pediatrics, Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Prasad N. Paradkar
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, VIC, Australia
| | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, California, United States of America
- Tata Institute for Genetics and Society-UCSD, La Jolla, California, United States of America
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18
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Suresh M, Jeevanandam J, Chan YS, Danquah MK, Kalaiarasi JMV. Opportunities for Metal Oxide Nanoparticles as a Potential Mosquitocide. BIONANOSCIENCE 2019. [DOI: 10.1007/s12668-019-00703-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Liu T, Yang WQ, Xie YG, Liu PW, Xie LH, Lin F, Li CY, Gu JB, Wu K, Yan GY, Chen XG. Construction of an efficient genomic editing system with CRISPR/Cas9 in the vector mosquito Aedes albopictus. INSECT SCIENCE 2019; 26:1045-1054. [PMID: 30311353 DOI: 10.1111/1744-7917.12645] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 09/04/2018] [Accepted: 09/17/2018] [Indexed: 06/08/2023]
Abstract
Aedes (Stegomyia) albopictus, also known as the Asian tiger mosquito, is a mosquito which originated in Asia. In recent years, it has become increasingly rampant throughout the world. This mosquito can transmit several arboviruses, including dengue, Zika and chikungunya viruses, and is considered a public health threat. Despite the urgent need of genome engineering to analyze specific gene functions, progress in genetical manipulation of Ae. albopictus has been slow due to a lack of efficient methods and genetic markers. In the present study, we established targeted disruptions in two genes, kynurenine hydroxylase (kh) and dopachrome conversion enzyme (yellow), to analyze the feasibility of generating visible phenotypes with genome editing by the clustered regularly interspaced short palindromic repeats (CRISPR) / CRISPR-associated protein 9 (Cas9) system in Ae. albopictus. Following Cas9 single guide RNA ribonucleoprotein injection into the posterior end of pre-blastoderm embryos, 30%-50% of fertile survivors produced alleles that failed to complement existing kh and yellow mutations. Complete eye and body pigmentation defects were readily observed in G1 pupae and adults, indicating successful generation of highly heritable mutations. We conclude that the CRISPR/Cas9-mediated gene editing system can be used in Ae. albopictus and that it can be adopted as an efficient tool for genome-scale analysis and biological study.
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Affiliation(s)
- Tong Liu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Wen-Qiang Yang
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Yu-Gu Xie
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Pei-Wen Liu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Li-Hua Xie
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Feng Lin
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Chen-Ying Li
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Jin-Bao Gu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Kun Wu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Gui-Yun Yan
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
| | - Xiao-Guang Chen
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China
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20
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Bui M, Shyong J, Lutz EK, Yang T, Li M, Truong K, Arvidson R, Buchman A, Riffell JA, Akbari OS. Live calcium imaging of Aedes aegypti neuronal tissues reveals differential importance of chemosensory systems for life-history-specific foraging strategies. BMC Neurosci 2019; 20:27. [PMID: 31208328 PMCID: PMC6580577 DOI: 10.1186/s12868-019-0511-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/10/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The mosquito Aedes aegypti has a wide variety of sensory pathways that have supported its success as a species as well as a highly competent vector of numerous debilitating infectious pathogens. Investigations into mosquito sensory systems and their effects on behavior are valuable resources for the advancement of mosquito control strategies. Numerous studies have elucidated key aspects of mosquito sensory systems, however there remains critical gaps within the field. In particular, compared to that of the adult form, there has been a lack of studies directed towards the immature life stages. Additionally, although numerous studies have pinpointed specific sensory receptors as well as responding motor outputs, there has been a lack of studies able to monitor both concurrently. RESULTS To begin filling aforementioned gaps, here we engineered Ae. aegypti to ubiquitously express a genetically encoded calcium indicator, GCaMP6s. Using this strain, combined with advanced microscopy, we simultaneously measured live stimulus-evoked calcium responses in both neuronal and muscle cells with a wide spatial range and resolution. CONCLUSIONS By coupling in vivo live calcium imaging with behavioral assays we were able to gain functional insights into how stimulus-evoked neural and muscle activities are represented, modulated, and transformed in mosquito larvae enabling us to elucidate mosquito sensorimotor properties important for life-history-specific foraging strategies.
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Affiliation(s)
- Michelle Bui
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | - Jennifer Shyong
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
| | - Eleanor K. Lutz
- Department of Biology, University of Washington, Seattle, WA 98195 USA
| | - Ting Yang
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | - Ming Li
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | - Kenneth Truong
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
| | - Ryan Arvidson
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
| | - Anna Buchman
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
| | | | - Omar S. Akbari
- Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093 USA
- Tata Institute for Genetics and Society, University of California, San Diego, La Jolla, CA 92093 USA
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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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22
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Establishment of a baculovirus-inducible CRISPR/Cas9 system for antiviral research in transgenic silkworms. Appl Microbiol Biotechnol 2018; 102:9255-9265. [PMID: 30151606 DOI: 10.1007/s00253-018-9295-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 10/28/2022]
Abstract
The CRISPR/Cas9 system is a powerful genetic engineering technique that has been widely used in gene therapy, as well as in the development of novel antimicrobials and transgenic insects. However, several challenges, including the lack of effective host target genes and the off-target effects, limit the application of CRISPR/Cas9 in insects. To mitigate these difficulties, we established a highly efficient virus-inducible CRISPR/Cas9 system in transgenic silkworms. This system includes the baculovirus-inducible promoter 39K, which directs transcription of the gene encoding, the Cas9 protein, and the U6 promoter which targets the sgATAD3A site of the ATPase family AAA domain-containing protein 3 (ATAD3A) gene. The double-positive transgenic line sgATAD3A×39K-Cas9 (ATAD3A-KO) was obtained by hybridization; antiviral activity in this hybrid transgenic line is induced only after Bombyx mori nucleopolyhedrovirus (BmNPV) infection. The BmNPV-inducible system significantly reduced off-target effects and did not affect the economically important characteristics of the transgenic silkworms. Most importantly, this novel system efficiently and consistently edited target genes, inhibiting BmNPV replication after the transgenic silkworms were inoculated with occlusion bodies (OBs). The suppression of BmNPV by the virus-inducible system was comparable to that of the stably expressed CRISPR/Cas9 system. Therefore, we successfully established a highly efficient BmNPV-inducible ATAD3A-KO transgenic silkworm line, with improved gene targeting specificity and antiviral efficiency. Our study thereby provides insights into the treatment of infectious diseases and into the control of insect pests.
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Strobl F, Anderl A, Stelzer EHK. A universal vector concept for a direct genotyping of transgenic organisms and a systematic creation of homozygous lines. eLife 2018; 7:e31677. [PMID: 29543587 PMCID: PMC5854464 DOI: 10.7554/elife.31677] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/29/2018] [Indexed: 12/25/2022] Open
Abstract
Diploid transgenic organisms are either hemi- or homozygous. Genetic assays are, therefore, required to identify the genotype. Our AGameOfClones vector concept uses two clearly distinguishable transformation markers embedded in interweaved, but incompatible Lox site pairs. Cre-mediated recombination leads to hemizygous individuals that carry only one marker. In the following generation, heterozygous descendants are identified by the presence of both markers and produce homozygous progeny that are selected by the lack of one marker. We prove our concept in Tribolium castaneum by systematically creating multiple functional homozygous transgenic lines suitable for long-term fluorescence live imaging. Our approach saves resources and simplifies transgenic organism handling. Since the concept relies on the universal Cre-Lox system, it is expected to work in all diploid model organisms, for example, insects, zebrafish, rodents and plants. With appropriate adaptions, it can be used in knock-out assays to preselect homozygous individuals and thus minimize the number of wasted animals.
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Affiliation(s)
- Frederic Strobl
- Physical Biology, BMLS, CEF-MCGoethe UniversitätFrankfurt am MainGermany
| | - Anita Anderl
- Physical Biology, BMLS, CEF-MCGoethe UniversitätFrankfurt am MainGermany
| | - Ernst HK Stelzer
- Physical Biology, BMLS, CEF-MCGoethe UniversitätFrankfurt am MainGermany
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Li M, Bui M, Yang T, Bowman CS, White BJ, Akbari OS. Germline Cas9 expression yields highly efficient genome engineering in a major worldwide disease vector, Aedes aegypti. Proc Natl Acad Sci U S A 2017; 114:E10540-E10549. [PMID: 29138316 PMCID: PMC5724270 DOI: 10.1073/pnas.1711538114] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The development of CRISPR/Cas9 technologies has dramatically increased the accessibility and efficiency of genome editing in many organisms. In general, in vivo germline expression of Cas9 results in substantially higher activity than embryonic injection. However, no transgenic lines expressing Cas9 have been developed for the major mosquito disease vector Aedes aegypti Here, we describe the generation of multiple stable, transgenic Ae. aegypti strains expressing Cas9 in the germline, resulting in dramatic improvements in both the consistency and efficiency of genome modifications using CRISPR. Using these strains, we disrupted numerous genes important for normal morphological development, and even generated triple mutants from a single injection. We have also managed to increase the rates of homology-directed repair by more than an order of magnitude. Given the exceptional mutagenic efficiency and specificity of the Cas9 strains we engineered, they can be used for high-throughput reverse genetic screens to help functionally annotate the Ae. aegypti genome. Additionally, these strains represent a step toward the development of novel population control technologies targeting Ae. aegypti that rely on Cas9-based gene drives.
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Affiliation(s)
- Ming Li
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Michelle Bui
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Ting Yang
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Christian S Bowman
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Bradley J White
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Omar S Akbari
- Department of Entomology, University of California, Riverside, CA 92521;
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
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Chen J, Aimanova K, Gill SS. Functional characterization of Aedes aegypti alkaline phosphatase ALP1 involved in the toxicity of Cry toxins from Bacillus thuringiensis subsp. israelensis and jegathesan. Peptides 2017; 98:78-85. [PMID: 28587836 PMCID: PMC5705450 DOI: 10.1016/j.peptides.2017.05.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/24/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Presently three major groups of proteins from Aedes aegypti, cadherin, alkaline phosphatases (ALP) and aminopeptidases N (APN), have been identified as Cry11Aa toxin receptors. To further characterize their role on toxicity, transgenic mosquitoes with silenced Aedes cadherin expression were previously generated and the role of cadherin in mediating the toxicity of four different mosquitocidal toxins (Cry11Aa, Cry11Ba, Cry4Aa and Cry4Ba) was demonstrated. Here, we investigated the role of another reported Cry11Aa receptor, ALP1. As with Aedes cadherin, this protein is localized in the apical cell membrane of distal and proximal gastric caecae and the posterior midgut. We also successfully generated transgenic mosquitoes that knockdowned ALP1 transcript levels using an inducible Aedes heat shock promoter, Hsp70A driving dsALP1RNA. Four different mosquitocidal toxins were used for larval bioassays against this transgenic mosquito. Bioassay results show thatCry11Aa toxicity to these transgenic larvae following a heat shock decreased (4.4 fold) and Cry11Ba toxicity is slightly attenuated. But Cry4Aa and Cry4Ba toxicity to ALP1 silenced larvae is unchanged. Without heat shock, toxicity of all four toxins does not change, suggesting this heat shock promoter is heat-inducible. Notably, transgenic mosquitoes with ALP1 knockdown are about 3.7 times less resistant to Cry11Aa toxin than those with Aedes cadherin knockdown. These results demonstrate that the ALP1 is an important secondary receptor for Cry11Aa and Cry11Ba, but it might not be involved in Cry4Aa and Cry4Ba toxicity.
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Affiliation(s)
- Jianwu Chen
- Departmentof Cell Biology and Neurosciences, University of California, Riverside, CA 92521, United States.
| | - Karly Aimanova
- Departmentof Cell Biology and Neurosciences, University of California, Riverside, CA 92521, United States
| | - Sarjeet S Gill
- Departmentof Cell Biology and Neurosciences, University of California, Riverside, CA 92521, United States
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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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Jupatanakul N, Sim S, Angleró-Rodríguez YI, Souza-Neto J, Das S, Poti KE, Rossi SL, Bergren N, Vasilakis N, Dimopoulos G. Engineered Aedes aegypti JAK/STAT Pathway-Mediated Immunity to Dengue Virus. PLoS Negl Trop Dis 2017; 11:e0005187. [PMID: 28081143 PMCID: PMC5230736 DOI: 10.1371/journal.pntd.0005187] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/15/2016] [Indexed: 12/31/2022] Open
Abstract
We have developed genetically modified Ae. aegypti mosquitoes that activate the conserved antiviral JAK/STAT pathway in the fat body tissue, by overexpressing either the receptor Dome or the Janus kinase Hop by the blood feeding-induced vitellogenin (Vg) promoter. Transgene expression inhibits infection with several dengue virus (DENV) serotypes in the midgut as well as systemically and in the salivary glands. The impact of the transgenes Dome and Hop on mosquito longevity was minimal, but it resulted in a compromised fecundity when compared to wild-type mosquitoes. Overexpression of Dome and Hop resulted in profound transcriptome regulation in the fat body tissue as well as the midgut tissue, pinpointing several expression signatures that reflect mechanisms of DENV restriction. Our transcriptome studies and reverse genetic analyses suggested that enrichment of DENV restriction factor and depletion of DENV host factor transcripts likely accounts for the DENV inhibition, and they allowed us to identify novel factors that modulate infection. Interestingly, the fat body-specific activation of the JAK/STAT pathway did not result in any enhanced resistance to Zika virus (ZIKV) or chikungunya virus (CHIKV) infection, thereby indicating a possible specialization of the pathway’s antiviral role. Dengue has represented a significant public health burden for a number of decades, and given the lack of dengue-specific drugs and limited availability of licensed vaccine, new methods for prevention and control are urgently needed. Here, we investigated whether genetic manipulation of the mosquitoes’ native JAK/STAT pathway-mediated anti-DENV defense system could be used to render mosquitoes more resistant to infection. We generated Ae. aegypti mosquitoes overexpressing the JAK/STAT pathway components Dome and Hop under the control of a bloodmeal-inducible, fat body-specific vitellogenin (Vg) promoter. These genetically modified mosquitoes showed an increased resistance to DENV infection, likely because of higher expression of DENV restriction factors and lower expression of DENV host factors, as indicated by transcriptome analyses. Expression of the transgenes had a minimal impact on mosquito longevity; however, it significantly impaired the mosquitoes’ fecundity. Interestingly, bloodmeal-inducible fat body-specific overexpression of either Hop or Dome did not affect mosquito permissiveness to either ZIKV or CHIKV infection, suggesting a possible specialization of JAK/STAT pathway antiviral defenses. Thus, our study is the first to provide a proof-of-concept that genetic engineering of the mosquitoes’ JAK/STAT immune pathway can be used to render this host more resistant to DENV infection.
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Affiliation(s)
- Natapong Jupatanakul
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Shuzhen Sim
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yesseinia I. Angleró-Rodríguez
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jayme Souza-Neto
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Suchismita Das
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Kristin E. Poti
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Shannan L. Rossi
- Department of Pathology and Center of Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Institute for Human Infections and Immunity, The University of Texas Medical Branch, Galveston TX, United States of America
| | - Nicholas Bergren
- Department of Pathology and Center of Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Institute for Human Infections and Immunity, The University of Texas Medical Branch, Galveston TX, United States of America
| | - Nikos Vasilakis
- Department of Pathology and Center of Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Institute for Human Infections and Immunity, The University of Texas Medical Branch, Galveston TX, United States of America
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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The sex locus is tightly linked to factors conferring sex-specific lethal effects in the mosquito Aedes aegypti. Heredity (Edinb) 2016; 117:408-416. [PMID: 27485667 DOI: 10.1038/hdy.2016.57] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 05/21/2016] [Accepted: 06/20/2016] [Indexed: 11/08/2022] Open
Abstract
In many taxa, sex chromosomes are heteromorphic and largely non-recombining. Evolutionary models predict that spread of recombination suppression on the Y chromosome is fueled by the accumulation of sexually antagonistic alleles in close linkage to the sex determination region. However, empirical evidence for the existence of sexually antagonistic alleles is scarce. In the mosquito Aedes aegypti, the sex-determining chromosomes are homomorphic. The region of suppressed recombination, which surrounds the male-specific sex-determining gene, remains very small, despite ancient origin of the sex chromosomes in the Aedes lineage. We conducted a genetic analysis of the A. aegypti chromosome region tightly linked to the sex locus. We used a strain with an enhanced green fluorescent protein (EGFP)-tagged transgene inserted near the male-determining gene to monitor crossing-over events close to the boundary of the sex-determining region (SDR), and to trace the inheritance pattern of the transgene in relation to sex. In a series of crossing experiments involving individuals with a recombinant sex chromosome we found developmental abnormalities leading to 1:2 sex biases, caused by lethality of half of the male or female progeny. Our results suggest that various factors causing sex-specific lethal effects are clustered within the neighborhood of the SDR, which in the affected sex are likely lost or gained through recombination, leading to death. These may include genes that are recessive lethal, vital for development and/or sexually antagonistic. The sex chromosome fragment in question represents a fascinating test case for the analysis of processes that shape stable boundaries of a non-recombining region.
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29
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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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30
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Das Gupta M, Chan SKS, Monteiro A. Natural Loss of eyeless/Pax6 Expression in Eyes of Bicyclus anynana Adult Butterflies Likely Leads to Exponential Decrease of Eye Fluorescence in Transgenics. PLoS One 2015; 10:e0132882. [PMID: 26173066 PMCID: PMC4501736 DOI: 10.1371/journal.pone.0132882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/22/2015] [Indexed: 12/03/2022] Open
Abstract
Commonly used visible markers for transgenesis use fluorescent proteins expressed at the surface of the body, such as in eyes. One commonly used marker is the 3xP3-EGFP cassette containing synthetic binding sites for the eyeless/Pax6 conserved transcription factor. This marker cassette leads to fluorescent eyes in a variety of animals tested so far. Here we show that upon reaching adulthood, transgenic Bicyclus anynana butterflies containing this marker cassette exponentially loose fluorescence in their eyes. After 12 days, transgenic individuals are no longer distinguishable from wild type individuals. The decreased eye fluorescence is likely due to significantly decreased or halted eyeless/Pax6 expression observed in wild type animals upon adult emergence. Implications from these findings include care in screening transgenic animals before these reach adulthood, or shortly thereafter, and in using adult animals of the same age for quantitative screening of likely homozygote and heterozygote individuals.
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Affiliation(s)
- Mainak Das Gupta
- Biological Sciences, National University of Singapore, Singapore
| | - Sam Kok Sim Chan
- Biological Sciences, Universiti Tunku Abdul Rahman, Kampar, Perak, Malaysia
| | - Antónia Monteiro
- Biological Sciences, National University of Singapore, Singapore
- Yale-NUS College, Singapore
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31
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Caroti F, Urbansky S, Wosch M, Lemke S. Germ line transformation and in vivo labeling of nuclei in Diptera: report on Megaselia abdita (Phoridae) and Chironomus riparius (Chironomidae). Dev Genes Evol 2015; 225:179-86. [PMID: 26044750 PMCID: PMC4460289 DOI: 10.1007/s00427-015-0504-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 05/20/2015] [Indexed: 11/28/2022]
Abstract
To understand how and when developmental traits of the fruit fly Drosophila melanogaster originated during the course of insect evolution, similar traits are functionally studied in variably related satellite species. The experimental toolkit available for relevant fly models typically comprises gene expression and loss as well as gain-of-function analyses. Here, we extend the set of available molecular tools to piggyBac-based germ line transformation in two satellite fly models, Megaselia abdita and Chironomus riparius. As proof-of-concept application, we used a Gateway variant of the piggyBac transposon vector pBac{3xP3-eGFPafm} to generate a transgenic line that expresses His2Av-mCherry as fluorescent nuclear reporter ubiquitously in the gastrulating embryo of M. abdita. Our results open two phylogenetically important nodes of the insect order Diptera for advanced developmental evolutionary genetics.
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Affiliation(s)
- Francesca Caroti
- Centre for Organismal Studies, Universität Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Silvia Urbansky
- Centre for Organismal Studies, Universität Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Maike Wosch
- Centre for Organismal Studies, Universität Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Steffen Lemke
- Centre for Organismal Studies, Universität Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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32
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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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33
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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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34
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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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35
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Arik AJ, Hun LV, Quicke K, Piatt M, Ziegler R, Scaraffia PY, Badgandi H, Riehle MA. Increased Akt signaling in the mosquito fat body increases adult survivorship. FASEB J 2014; 29:1404-13. [PMID: 25550465 DOI: 10.1096/fj.14-261479] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/30/2014] [Indexed: 11/11/2022]
Abstract
Akt signaling regulates diverse physiologies in a wide range of organisms. We examine the impact of increased Akt signaling in the fat body of 2 mosquito species, the Asian malaria mosquito Anopheles stephensi and the yellow fever mosquito Aedes aegypti. Overexpression of a myristoylated and active form of A. stephensi and Ae. aegypti Akt in the fat body of transgenic mosquitoes led to activation of the downstream signaling molecules forkhead box O (FOXO) and p70 S6 kinase in a tissue and blood meal-specific manner. In both species, increased Akt signaling in the fat body after blood feeding significantly increased adult survivorship relative to nontransgenic sibling controls. In A. stephensi, survivorship was increased by 15% to 45%, while in Ae. aegypti, it increased 14% to 47%. Transgenic mosquitoes fed only sugar, and thus not expressing active Akt, had no significant difference in survivorship relative to nontransgenic siblings. Expression of active Akt also increased expression of fat body vitellogenin, but the number of viable eggs did not differ significantly between transgenic and nontransgenic controls. This work demonstrates a novel mechanism of enhanced survivorship through increased Akt signaling in the fat bodies of multiple mosquito genera and provides new tools to unlock the molecular underpinnings of aging in eukaryotic organisms.
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Affiliation(s)
- Anam J Arik
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Lewis V Hun
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Kendra Quicke
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Michael Piatt
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Rolf Ziegler
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Patricia Y Scaraffia
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Hemant Badgandi
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Michael A Riehle
- *Department of Entomology, University of Arizona, Tucson, Arizona, USA; Department of Pediatrics, Emory University, Atlanta, Georgia, USA; Department of Tropical Medicine, Vector-Borne Infectious Diseases Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA; and Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
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Abstract
Recent advances in genetic engineering are bringing new promise for controlling mosquito populations that transmit deadly pathogens. Here we discuss past and current efforts to engineer mosquito strains that are refractory to disease transmission or are suitable for suppressing wild disease-transmitting populations.
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Affiliation(s)
| | - Andrea Smidler
- />Department of Immunology and Infectious Diseases, Harvard School of Public Health, Avenue Louis Pasteur, Boston, MA 021155 USA
- />Department of Genetics, Harvard Medical School, Avenue Louis Pasteur, Boston, MA 02115 USA
| | - Flaminia Catteruccia
- />Department of Immunology and Infectious Diseases, Harvard School of Public Health, Avenue Louis Pasteur, Boston, MA 021155 USA
- />Department of Microbiology, Perugia University, Perugia, 06100 Italy
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Lok J. piggyBac: A vehicle for integrative DNA transformation of parasitic nematodes. Mob Genet Elements 2014; 3:e24417. [PMID: 23914309 PMCID: PMC3681738 DOI: 10.4161/mge.24417] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 03/11/2013] [Accepted: 03/22/2013] [Indexed: 12/18/2022] Open
Abstract
In addition to their natural role in eukaryotic genome evolution, transposons can be powerful tools for functional genomics in diverse taxa. The piggyBac transposon has been applied as such in eukaryotic parasites, both protozoa and helminths, and in several important vector mosquitoes. piggyBac is advantageous for functional genomics because of its ability to transduce a wide range of taxa, its capacity to integrate large DNA ‘cargoes’ relative to other mobile genetic elements, its propensity to target transcriptional units and its ability to re-mobilize without leaving a pattern of non-excised sequences or ‘footprint’ in the genome. We recently demonstrated that piggyBac can integrate transgenes into the genome of the parasitic nematode Strongyloides ratti, an important model for parasitic nematode biology and a close relative of the significant human pathogen S. stercoralis. Unlike transgenes encoded in conventional plasmid vectors, which we assume are assembled into multi-copy episomal arrays as they are in Caenorhabditis elegans, transgenes integrated via piggyBac are not only stably inherited in S. ratti, they are also continuously expressed. This has allowed derivation of the first stable transgene expressing lines in any parasitic nematode, a significant advance in the development of functional genomic tools for these important pathogens.
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Affiliation(s)
- James Lok
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA USA
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38
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Reeves RG, Bryk J, Altrock PM, Denton JA, Reed FA. First steps towards underdominant genetic transformation of insect populations. PLoS One 2014; 9:e97557. [PMID: 24844466 PMCID: PMC4028297 DOI: 10.1371/journal.pone.0097557] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/08/2014] [Indexed: 11/18/2022] Open
Abstract
The idea of introducing genetic modifications into wild populations of insects to stop them from spreading diseases is more than 40 years old. Synthetic disease refractory genes have been successfully generated for mosquito vectors of dengue fever and human malaria. Equally important is the development of population transformation systems to drive and maintain disease refractory genes at high frequency in populations. We demonstrate an underdominant population transformation system in Drosophila melanogaster that has the property of being both spatially self-limiting and reversible to the original genetic state. Both population transformation and its reversal can be largely achieved within as few as 5 generations. The described genetic construct {Ud} is composed of two genes; (1) a UAS-RpL14.dsRNA targeting RNAi to a haploinsufficient gene RpL14 and (2) an RNAi insensitive RpL14 rescue. In this proof-of-principle system the UAS-RpL14.dsRNA knock-down gene is placed under the control of an Actin5c-GAL4 driver located on a different chromosome to the {Ud} insert. This configuration would not be effective in wild populations without incorporating the Actin5c-GAL4 driver as part of the {Ud} construct (or replacing the UAS promoter with an appropriate direct promoter). It is however anticipated that the approach that underlies this underdominant system could potentially be applied to a number of species.
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Affiliation(s)
- R. Guy Reeves
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- * E-mail:
| | - Jarosław Bryk
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Philipp M. Altrock
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Jai A. Denton
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Floyd A. Reed
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
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Akbari OS, Papathanos PA, Sandler JE, Kennedy K, Hay BA. Identification of germline transcriptional regulatory elements in Aedes aegypti. Sci Rep 2014; 4:3954. [PMID: 24492376 PMCID: PMC3912481 DOI: 10.1038/srep03954] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 01/16/2014] [Indexed: 12/18/2022] Open
Abstract
The mosquito Aedes aegypti is the principal vector for the yellow fever and dengue viruses, and is also responsible for recent outbreaks of the alphavirus chikungunya. Vector control strategies utilizing engineered gene drive systems are being developed as a means of replacing wild, pathogen transmitting mosquitoes with individuals refractory to disease transmission, or bringing about population suppression. Several of these systems, including Medea, UD(MEL), and site-specific nucleases, which can be used to drive genes into populations or bring about population suppression, utilize transcriptional regulatory elements that drive germline-specific expression. Here we report the identification of multiple regulatory elements able to drive gene expression specifically in the female germline, or in the male and female germline, in the mosquito Aedes aegypti. These elements can also be used as tools with which to probe the roles of specific genes in germline function and in the early embryo, through overexpression or RNA interference.
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Affiliation(s)
- Omar S Akbari
- 1] Division of Biology, MC 156-29, California Institute of Technology, Pasadena, CA 91125, USA [2]
| | - Philippos A Papathanos
- 1] Division of Biology, MC 156-29, California Institute of Technology, Pasadena, CA 91125, USA [2]
| | - Jeremy E Sandler
- Division of Biology, MC 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Katie Kennedy
- Division of Biology, MC 156-29, California Institute of Technology, Pasadena, CA 91125, USA
| | - Bruce A Hay
- Division of Biology, MC 156-29, California Institute of Technology, Pasadena, CA 91125, USA
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Wright JA, Smith RC, Xie K, Craig NL, Atkinson PW. IPB7 transposase behavior in Drosophila melanogaster and Aedes aegypti. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:899-906. [PMID: 23835045 PMCID: PMC3888874 DOI: 10.1016/j.ibmb.2013.06.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 06/27/2013] [Accepted: 06/27/2013] [Indexed: 06/02/2023]
Abstract
Transposons are used in insect science as genetic tools that enable the transformation of insects and the identification and isolation of genes though their ability to insert in or near to them. Four transposons, piggyBac, Mos1, Hermes and Minos are commonly used in insects beyond Drosophila melanogaster with piggyBac, due to its wide host range and frequency of transposition, being the most commonly chosen. The utility of these transposons as genetic tools is directly proportional to their activity since higher transposition rates would be expected to lead to higher transformation frequencies and higher frequencies of insertion throughout the genome. As a consequence there is an ongoing need for hyperactive transposases for use in insect genetics, however these have proven difficult to obtain. IPB7 is a hyperactive mutant of the piggyBac transposase that was identified by a genetic screen performed in yeast, a mammalian codon optimized version of which was then found to be highly active in rodent embryonic stem cells with no apparent deleterious effects. Here we report the activity of IPB7 in D. melanogaster and the mosquito, Aedes aegypti. Somatic transposition assays revealed an increase in IPB7's transposition rate from wild-type piggyBac transposase in D. melanogaster but not Ae. aegypti. However the use of IPB7 in D. melanogaster genetic transformations produced a high rate of sterility and a low transformation rate compared to wild-type transposase. This high rate of sterility was accompanied by significant gonadal atrophy that was also observed in the absence of the piggyBac vector transposon. We conclude that IPB7 has increased activity in the D. melanogaster germ-line but that a component of the sterility associated with its activity is independent of the presence of the piggyBac transposon.
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Affiliation(s)
- Jennifer A. Wright
- Department of Entomology, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 212205-2185, USA
| | - Ryan C. Smith
- Cell Molecular and Developmental Biology Graduate Program, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 212205-2185, USA
| | - Kefong Xie
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 212205-2185, USA
| | - Nancy L. Craig
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 212205-2185, USA
| | - Peter W. Atkinson
- Department of Entomology, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 212205-2185, USA
- Cell Molecular and Developmental Biology Graduate Program, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 212205-2185, USA
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University California Riverside, Riverside, CA 92521, USA
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41
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Carballar-Lejarazú R, Jasinskiene N, James AA. Exogenous gypsy insulator sequences modulate transgene expression in the malaria vector mosquito, Anopheles stephensi. Proc Natl Acad Sci U S A 2013; 110:7176-81. [PMID: 23584017 PMCID: PMC3645527 DOI: 10.1073/pnas.1304722110] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malaria parasites are transmitted to humans by mosquitoes of the genus Anopheles, and these insects are the targets of innovative vector control programs. Proposed approaches include the use of genetic strategies based on transgenic mosquitoes to suppress or modify vector populations. Although substantial advances have been made in engineering resistant mosquito strains, limited efforts have been made in refining mosquito transgene expression, in particular attenuating the effects of insertions sites, which can result in variations in phenotypes and impacts on fitness due to the random integration of transposon constructs. A promising strategy to mitigate position effects is the identification of insulator or boundary DNA elements that could be used to isolate transgenes from the effects of their genomic environment. We applied quantitative approaches that show that exogenous insulator-like DNA derived from the Drosophila melanogaster gypsy retrotransposon can increase and stabilize transgene expression in transposon-mediated random insertions and recombinase-catalyzed, site-specific integrations in the malaria vector mosquito, Anopheles stephensi. These sequences can contribute to precise expression of transgenes in mosquitoes engineered for both basic and applied goals.
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Affiliation(s)
- Rebeca Carballar-Lejarazú
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900; and
| | - Nijole Jasinskiene
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900; and
| | - Anthony A. James
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900; and
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697-4500
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42
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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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Carpenetti TLG, Aryan A, Myles KM, Adelman ZN. Robust heat-inducible gene expression by two endogenous hsp70-derived promoters in transgenic Aedes aegypti. INSECT MOLECULAR BIOLOGY 2012; 21:97-106. [PMID: 22142225 PMCID: PMC3259147 DOI: 10.1111/j.1365-2583.2011.01116.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Aedes aegypti is an important vector of the viruses that cause dengue fever, dengue haemorrhagic fever and yellow fever. Reverse genetic approaches to the study of gene function in this mosquito have been limited by the lack of a robust inducible promoter to allow precise temporal control over a protein-encoding or hairpin RNA transgene. Likewise, investigations into the molecular and biochemical basis of vector competence would benefit from the ability to activate an antipathogen molecule at specific times during infection. We have characterized the ability of genomic sequences derived from two Ae. aegypti heat shock protein 70 (hsp70) genes to drive heat-inducible expression of a reporter in both transient and germline transformation contexts. AaHsp70-luciferase transcripts accumulated specifically after heat shock, and displayed a pattern of rapid induction and decay similar to endogenous AaHsp70 genes. Luciferase expression in transgenic Ae. aegypti increased by ~25-50-fold in whole adults by 4 h after heat-shock, with significant activity (~20-fold) remaining at 24 h. Heat-induced expression was even more dramatic in midgut tissues, with one strain showing a ~2500-fold increase in luciferase activity. The AaHsp70 promoters described could be valuable for gene function studies as well as for the precise timing of the expression of antipathogen molecules.
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Affiliation(s)
- T L G Carpenetti
- Fralin Life Science Institute and Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA
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44
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Abstract
The ability to introduce genetic constructs of choice into the genome of Anopheles mosquitoes provides a valuable tool to study the molecular interactions between the Plasmodium parasite and its insect host. In the long term, this technology could potentially offer new ways to control vector-borne diseases through the suppression of target mosquito populations or through the introgression of traits that preclude pathogen transmission. Here, we describe in detail protocols for the generation of transgenic Anopheles gambiae mosquitoes based on germ-line transformation using either modified transposable elements or the site-specific PhiC31 recombinase.
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45
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Arensburger P, Hice RH, Wright JA, Craig NL, Atkinson PW. The mosquito Aedes aegypti has a large genome size and high transposable element load but contains a low proportion of transposon-specific piRNAs. BMC Genomics 2011; 12:606. [PMID: 22171608 PMCID: PMC3259105 DOI: 10.1186/1471-2164-12-606] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 12/15/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The piRNA pathway has been shown in model organisms to be involved in silencing of transposons thereby providing genome stability. In D. melanogaster the majority of piRNAs map to these sequences. The medically important mosquito species Aedes aegypti has a large genome size, a high transposon load which includes Miniature Inverted repeat Transposable Elements (MITES) and an expansion of the piRNA biogenesis genes. Studies of transgenic lines of Ae. aegypti have indicated that introduced transposons are poorly remobilized and we sought to explore the basis of this. We wished to analyze the piRNA profile of Ae. aegypti and thereby determine if it is responsible for transposon silencing in this mosquito. RESULTS Estimated piRNA sequence diversity was comparable between Ae. aegypti and D. melanogaster, but surprisingly only 19% of mosquito piRNAs mapped to transposons compared to 51% for D. melanogaster. Ae. aegypti piRNA clusters made up a larger percentage of the total genome than those of D. melanogaster but did not contain significantly higher percentages of transposon derived sequences than other regions of the genome. Ae. aegypti contains a number of protein coding genes that may be sources of piRNA biogenesis with two, traffic jam and maelstrom, implicated in this process in model organisms. Several genes of viral origin were also targeted by piRNAs. Examination of six mosquito libraries that had previously been transformed with transposon derived sequence revealed that new piRNA sequences had been generated to the transformed sequences, suggesting that they may have stimulated a transposon inactivation mechanism. CONCLUSIONS Ae. aegypti has a large piRNA complement that maps to transposons but primarily gene sequences, including many viral-derived sequences. This, together the more uniform distribution of piRNA clusters throughout its genome, suggest that some aspects of the piRNA system differ between Ae. aegypti and D. melanogaster.
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Affiliation(s)
- Peter Arensburger
- Center for Disease Vector Research, Institute for Integrative Genome Biology, and Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Robert H Hice
- Center for Disease Vector Research, Institute for Integrative Genome Biology, and Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Jennifer A Wright
- Center for Disease Vector Research, Institute for Integrative Genome Biology, and Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Nancy L Craig
- Department of Molecular Biology & Genetics and Howard Hughes Medical Institute, Johns Hopkins School of Medicine, Baltimore, MD 20742,USA
| | - Peter W Atkinson
- Center for Disease Vector Research, Institute for Integrative Genome Biology, and Department of Entomology, University of California, Riverside, CA 92521, USA
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46
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Kokoza VA, Raikhel AS. Targeted gene expression in the transgenic Aedes aegypti using the binary Gal4-UAS system. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:637-44. [PMID: 21536128 PMCID: PMC3124619 DOI: 10.1016/j.ibmb.2011.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 04/11/2011] [Accepted: 04/13/2011] [Indexed: 05/04/2023]
Abstract
In this study, we report the establishment of the binary Gal4/UAS system for the yellow fever mosquito Aedes aegypti. We utilized the 1.8-kb 5' upstream region of the vitellogenin gene (Vg) to genetically engineer mosquito lines with the Vg-Gal4 activator and established UAS-EGFP responder transgenic mosquito lines to evaluate the binary Gal4/UAS system. The results show that the Vg-Gal4 driver leads to a high level of tissue-, stage- and sex-specific expression of the EGFP reporter in the fat body of Vg-Gal4/UAS-EGFP hybrids after blood-meal activation. In addition, the applicability of this system to study hormonal regulation of gene expression was demonstrated in in vitro organ culture experiments in which the EGFP reporter was highly activated in isolated fat bodies of previtellogenic Vg-Gal4/UAS-EGFP females incubated in the presence of 20-hydroxyecdysone (20E). Hence, this study has opened the door for further refinement of genetic tools in mosquitoes.
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Nolan T, Petris E, Müller HM, Cronin A, Catteruccia F, Crisanti A. Analysis of two novel midgut-specific promoters driving transgene expression in Anopheles stephensi mosquitoes. PLoS One 2011; 6:e16471. [PMID: 21326609 PMCID: PMC3033896 DOI: 10.1371/journal.pone.0016471] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 12/17/2010] [Indexed: 01/21/2023] Open
Abstract
Background Tissue-specific promoters controlling the expression of transgenes in Anopheles mosquitoes represent a valuable tool both for studying the interaction between these malaria vectors and the Plasmodium parasites they transmit and for novel malaria control strategies based on developing Plasmodium-refractory mosquitoes by expressing anti-parasitic genes. With this aim we have studied the promoter regions of two genes from the most important malaria vector, Anopheles gambiae, whose expression is strongly induced upon blood feeding. Results We analysed the A. gambiae Antryp1 and G12 genes, which we have shown to be midgut-specific and maximally expressed at 24 hours post-bloodmeal (PBM). Antryp1, required for bloodmeal digestion, encodes one member of a family of 7 trypsin genes. The G12 gene, of unknown function, was previously identified in our laboratory in a screen for genes induced in response to a bloodmeal. We fused 1.1 kb of the upstream regions containing the putative promoter of these genes to reporter genes and transformed these into the Indian malaria vector A. stephensi to see if we could recapitulate the expression pattern of the endogenous genes. Both the Antryp1 and G12 upstream regions were able to drive female-predominant, midgut-specific expression in transgenic mosquitoes. Expression of the Antryp1-driven reporter in transgenic A. stephensi lines was low, undetectable by northern blot analysis, and failed to fully match the induction kinetics of the endogenous Antryp1 gene in A. gambiae. This incomplete conservation of expression suggests either subtle differences in the transcriptional machinery between A. stephensi and A. gambiae or that the upstream region chosen lacked all the control elements. In contrast, the G12 upstream region was able to faithfully reproduce the expression profile of the endogenous A. gambiae gene, showing female midgut specificity in the adult mosquito and massive induction PBM, peaking at 24 hours. Conclusions Our studies on two putative blood-meal induced, midgut-specific promoters validate the use of G12 upstream regulatory regions to drive targeted transgene expression coinciding spatially and temporally with pre-sporogonic stages of Plasmodium parasites in the mosquito, offering the possibility of manipulating vector competence or performing functional studies on vector-parasite interactions.
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Affiliation(s)
- Tony Nolan
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Elisa Petris
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Hans-Michael Müller
- Heidelberg University Biochemistry Centre, Heidelberg University, Heidelberg, Germany
| | - Ann Cronin
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Flaminia Catteruccia
- Department of Life Sciences, Imperial College London, London, United Kingdom
- University of Perugia, Perugia, Italy
- * E-mail: (FC); (ACrisanti)
| | - Andrea Crisanti
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail: (FC); (ACrisanti)
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Warren IA, Fowler K, Smith H. Germline transformation of the stalk-eyed fly, Teleopsis dalmanni. BMC Mol Biol 2010; 11:86. [PMID: 21080934 PMCID: PMC2999598 DOI: 10.1186/1471-2199-11-86] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 11/16/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Stalk-eyed flies of the family Diopsidae have proven to be an excellent model organism for studying the evolution of ornamental sexual traits. In diopsid flies the eyes and antennae are borne at the end of lateral head projections called 'eye-stalks'. Eyespan, the distance between the eyes, and the degree of sexual dimorphism in eyespan vary considerably between species and several sexually dimorphic species show sexual selection through female mate preference for males with exaggerated eyespan. Relatively little is known about the molecular genetic basis of intra- or inter-species variation in eyespan, eye-stalk development or growth regulation in diopsids. Molecular approaches including comparative developmental analyses, EST screening and QTL mapping have identified potential candidate loci for eyespan regulation in the model species Teleopsis dalmanni. Functional analyses of these genes to confirm and fully characterise their roles in eye-stalk growth require the development of techniques such as germline transformation to manipulate gene activity in vivo. RESULTS We used in vivo excision assays to identify transposon vector systems with the activity required to mediate transgenesis in T. dalmanni. Mariner based vectors showed no detectable excision while both Minos and piggyBac were active in stalk-eyed fly embryos. Germline transformation with an overall efficiency of 4% was achieved using a Minos based vector and the 3xP3-EGFP marker construct. Chromosomal insertion of constructs was confirmed by Southern blot analysis. Both autosomal and X-linked inserts were recovered. A homozygous stock, established from one of the X-linked inserts, has maintained stable expression for eight generations. CONCLUSIONS We have performed stable germline transformation of a stalk-eyed fly, T. dalmanni. This is the first transgenic protocol to be developed in an insect species that exhibits an exaggerated male sexual trait. Transgenesis will enable the development of a range of techniques for analysing gene function in this species and so provide insight into the mechanisms underlying the development of a morphological trait subject to sexual selection. Our X-linked insertion line will permit the sex of live larvae to be determined. This will greatly facilitate the identification of genes which are differentially expressed during eye-stalk development in males and females.
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Affiliation(s)
- Ian A Warren
- Department of Genetics, Evolution & Environment, University College London, London, UK
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Labbé GMC, Nimmo DD, Alphey L. piggybac- and PhiC31-mediated genetic transformation of the Asian tiger mosquito, Aedes albopictus (Skuse). PLoS Negl Trop Dis 2010; 4:e788. [PMID: 20808959 PMCID: PMC2923142 DOI: 10.1371/journal.pntd.0000788] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 07/12/2010] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The Asian tiger mosquito, Aedes albopictus (Skuse), is a vector of several arboviruses including dengue and chikungunya. This highly invasive species originating from Southeast Asia has travelled the world in the last 30 years and is now established in Europe, North and South America, Africa, the Middle East and the Caribbean. In the absence of vaccine or antiviral drugs, efficient mosquito control strategies are crucial. Conventional control methods have so far failed to control Ae. albopictus adequately. METHODOLOGY/PRINCIPAL FINDINGS Germline transformation of Aedes albopictus was achieved by micro-injection of embryos with a piggyBac-based transgene carrying a 3xP3-ECFP marker and an attP site, combined with piggyBac transposase mRNA and piggyBac helper plasmid. Five independent transgenic lines were established, corresponding to an estimated transformation efficiency of 2-3%. Three lines were re-injected with a second-phase plasmid carrying an attB site and a 3xP3-DsRed2 marker, combined with PhiC31 integrase mRNA. Successful site-specific integration was observed in all three lines with an estimated transformation efficiency of 2-6%. CONCLUSIONS/SIGNIFICANCE Both piggybac- and site-specific PhiC31-mediated germline transformation of Aedes albopictus were successfully achieved. This is the first report of Ae. albopictus germline transformation and engineering, a key step towards studying and controlling this species using novel molecular techniques and genetic control strategies.
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Affiliation(s)
- Geneviève M. C. Labbé
- Oxitec Limited, Oxford, United Kingdom
- Division of Biology, Imperial College London Silwood Park, Ascot, United Kingdom
| | | | - Luke Alphey
- Oxitec Limited, Oxford, United Kingdom
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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Anderson MAE, Gross TL, Myles KM, Adelman ZN. Validation of novel promoter sequences derived from two endogenous ubiquitin genes in transgenic Aedes aegypti. INSECT MOLECULAR BIOLOGY 2010; 19:441-9. [PMID: 20456509 PMCID: PMC3605713 DOI: 10.1111/j.1365-2583.2010.01005.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
To date, only a limited number of promoter sequences have been described to drive transgene expression in the disease vector Aedes aegypti. We sought to increase this repertoire by characterizing the ability of upstream sequences derived from the Ae. aegypti Ub(L40) and polyubiquitin genes to drive the expression of marker proteins. Both genomic fragments were able to drive robust expression of luciferase in cultured mosquito cells. Following Mos1-transformation, the Ub(L40) promoter drove strong expression of a fluorescent marker in early larvae and in ovaries, while the polyubiquitin promoter drove robust EGFP expression in all stages of development, including constitutive expression throughout the midgut. These promoter fragments provide two new expression profiles for future Ae. aegypti genetic experiments.
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Affiliation(s)
| | | | | | - Zach N. Adelman
- corresponding author: Zach N. Adelman, 305 Fralin Life Science Institute, West Campus Dr. Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, , 540 231-6614 (phone), 540 231-9131 (fax)
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