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Abstract
CRISPR-mediated genome engineering technologies have been adapted to a wide variety of organisms with high efficiency and specificity. The yellow fever mosquito, Aedes aegypti , is one such organism. It is also responsible for transmitting a wide variety of deadly viruses including Dengue, Zika, Yellow fever, and Chikungunya. The key to successful CRISPR-mediated gene editing applications is the delivery of both Cas9 ribonuclease and single-guide RNA (sgRNA ) to the nucleus of desired cells. Various methods have been developed for supplying the Cas9 endonuclease, sgRNA , and donor DNA to Ae. aegypti. In this chapter, we focus on methods of direct embryo delivery of editing components, presenting detailed step-by-step CRISPR/Cas9-based genome-editing protocols for inducing desired heritable edits in mosquitoes as well as insights into successful application of these protocols. We also highlight potential opportunities for customizing these protocols to manipulate the mosquito genome for innovative in vivo gene function studies.
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Affiliation(s)
- Ruichen Sun
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Ming Li
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Conor J McMeniman
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Omar S Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.
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Yokoi K, Tsubota T, Jouraku A, Sezutsu H, Bono H. Reference Transcriptome Data in Silkworm Bombyx mori. INSECTS 2021; 12:519. [PMID: 34205145 PMCID: PMC8228281 DOI: 10.3390/insects12060519] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/17/2021] [Accepted: 05/28/2021] [Indexed: 11/30/2022]
Abstract
Herein, we performed RNA-seq analysis of ten major tissues/subparts of silkworm larvae. The sequences were mapped onto the reference genome assembly and the reference transcriptome data were successfully constructed. The reference data provided a nearly complete sequence for sericin-1, a major silk gene with a complex structure. We also markedly improved the gene model for other genes. The transcriptomic expression was investigated in each tissue and a number of transcripts were identified that were exclusively expressed in tissues such as the testis. Transcripts strongly expressed in the midgut formed tight genomic clusters, suggesting that they originated from tandem gene duplication. Transcriptional factor genes expressed in specific tissues or the silk gland subparts were also identified. We successfully constructed reference transcriptome data in the silkworm and found that a number of transcripts showed unique expression profiles. These results will facilitate basic studies on the silkworm and accelerate its applications, which will contribute to further advances in lepidopteran and entomological research as well as the practical use of these insects.
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Affiliation(s)
- Kakeru Yokoi
- Insect Genome Research and Engineering Unit, Division of Applied Genetics, Institute of Agrobiological Sciences (NIAS), National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan;
- Research Center for Agricultural Information Technology (RCAIT), National Agriculture and Food Research Organization (NARO), Kintetsu Kasumigaseki Building Kasumigaseki 3-5-1, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Takuya Tsubota
- Transgenic Silkworm Research Unit, Division of Biotechnology, Institute of Agrobiological Sciences (NIAS), National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan; (T.T.); (H.S.)
| | - Akiya Jouraku
- Insect Genome Research and Engineering Unit, Division of Applied Genetics, Institute of Agrobiological Sciences (NIAS), National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan;
| | - Hideki Sezutsu
- Transgenic Silkworm Research Unit, Division of Biotechnology, Institute of Agrobiological Sciences (NIAS), National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan; (T.T.); (H.S.)
| | - Hidemasa Bono
- Database Center for Life Science (DBCLS), Joint Support-Center for Data Science Research, Research Organization of Information and Systems, 1111 Yata, Mishima, Shizuoka 411-8540, Japan;
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-0046, Japan
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A comparative genomic approach using mouse and fruit fly data to discover genes involved in testis function in hymenopterans with a focus on Nasonia vitripennis. BMC Ecol Evol 2021; 21:90. [PMID: 34011283 PMCID: PMC8132408 DOI: 10.1186/s12862-021-01825-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 05/12/2021] [Indexed: 11/18/2022] Open
Abstract
Background Spermatogenesis appears to be a relatively well-conserved process even among distantly related animal taxa such as invertebrates and vertebrates. Although Hymenopterans share many characteristics with other organisms, their complex haplodiploid reproduction system is still relatively unknown. However, they serve as a complementary insect model to Drosophila for studying functional male fertility. In this study, we used a comparative method combining taxonomic, phenotypic data and gene expression to identify candidate genes that could play a significant role in spermatogenesis in hymenopterans. Results Of the 546 mouse genes predominantly or exclusively expressed in the mouse testes, 36% had at least one ortholog in the fruit fly. Of these genes, 68% had at least one ortholog in one of the six hymenopteran species we examined. Based on their gene expression profiles in fruit fly testes, 71 of these genes were hypothesized to play a marked role in testis function. Forty-three of these 71 genes had an ortholog in at least one of the six hymenopteran species examined, and their enriched GO terms were related to the G2/M transition or to cilium organization, assembly, or movement. Second, of the 379 genes putatively involved in male fertility in Drosophila, 224 had at least one ortholog in each of the six Hymenoptera species. Finally, we showed that 199 of these genes were expressed in early pupal testis in Nasonia vitripennis; 86 exhibited a high level of expression, and 54 displayed modulated expression during meiosis. Conclusions In this study combining phylogenetic and experimental approaches, we highlighted genes that may have a major role in gametogenesis in hymenopterans; an essential prerequisite for further research on functional importance of these genes. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01825-6.
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Chaverra-Rodriguez D, Dalla Benetta E, Heu CC, Rasgon JL, Ferree PM, Akbari OS. Germline mutagenesis of Nasonia vitripennis through ovarian delivery of CRISPR-Cas9 ribonucleoprotein. INSECT MOLECULAR BIOLOGY 2020; 29:569-577. [PMID: 32715554 DOI: 10.1111/imb.12663] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/19/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
CRISPR/Cas9 gene editing is a powerful technology to study the genetics of rising model organisms, such as the jewel wasp Nasonia vitripennis. However, current methods involving embryonic microinjection of CRISPR reagents are challenging. Delivery of Cas9 ribonucleoprotein into female ovaries is an alternative that has only been explored in a small handful of insects, such as mosquitoes, whiteflies and beetles. Here, we developed a simple protocol for germline gene editing by injecting Cas9 ribonucleoprotein in adult N. vitripennis females using either ReMOT control (Receptor-Mediated Ovary Transduction of Cargo) or BAPC (Branched Amphiphilic Peptide Capsules) as ovary delivery methods. For ReMOT Control we used the Drosophila melanogaster-derived peptide 'P2C' fused to EGFP to visualize the ovary delivery, and fused to Cas9 protein for gene editing of the cinnabar gene using saponin as an endosomal escape reagent. For BAPC we optimized the concentrations of protein, sgRNA and the transfection reagent. We demonstrate delivery of protein cargo such as EGFP and Cas9 into developing oocytes via P2C peptide and BAPC. Additionally, somatic and germline gene editing were demonstrated. This approach will greatly facilitate CRISPR-applied genetic manipulation in this and other rising model organisms.
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Affiliation(s)
- D Chaverra-Rodriguez
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA, USA
| | - E Dalla Benetta
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA, USA
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, USA
| | - C C Heu
- Department of Entomology, The Pennsylvania State University, University Park, PA, USA
- The Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - J L Rasgon
- Department of Entomology, The Pennsylvania State University, University Park, PA, USA
- The Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - P M Ferree
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, USA
| | - O S Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California, San Diego, CA, USA
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Lester PJ, Bulgarella M, Baty JW, Dearden PK, Guhlin J, Kean JM. The potential for a CRISPR gene drive to eradicate or suppress globally invasive social wasps. Sci Rep 2020; 10:12398. [PMID: 32709966 PMCID: PMC7382497 DOI: 10.1038/s41598-020-69259-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 07/09/2020] [Indexed: 12/14/2022] Open
Abstract
CRISPR gene drives have potential for widespread and cost-efficient pest control, but are highly controversial. We examined a potential gene drive targeting spermatogenesis to control the invasive common wasp (Vespula vulgaris) in New Zealand. Vespula wasps are haplodiploid. Their life cycle makes gene drive production challenging, as nests are initiated by single fertilized queens in spring followed by several cohorts of sterile female workers and the production of reproductives in autumn. We show that different spermatogenesis genes have different levels of variation between introduced and native ranges, enabling a potential 'precision drive' that could target the reduced genetic diversity and genotypes within the invaded range. In vitro testing showed guide-RNA target specificity and efficacy that was dependent on the gene target within Vespula, but no cross-reactivity in other Hymenoptera. Mathematical modelling incorporating the genetic and life history traits of Vespula wasps identified characteristics for a male sterility drive to achieve population control. There was a trade-off between drive infiltration and impact: a drive causing complete male sterility would not spread, while partial sterility could be effective in limiting population size if the homing rate is high. Our results indicate that gene drives may offer viable suppression for wasps and other haplodiploid pests.
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Affiliation(s)
- Philip J Lester
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
| | - Mariana Bulgarella
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
| | - James W Baty
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
| | - Peter K Dearden
- Genomics Aotearoa and Biochemistry Department, University of Otago, Dunedin, New Zealand
| | - Joseph Guhlin
- Genomics Aotearoa and Biochemistry Department, University of Otago, Dunedin, New Zealand
| | - John M Kean
- AgResearch Limited, Hamilton, 3240, New Zealand
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Ferree PM, Aldrich JC, Jing XA, Norwood CT, Van Schaick MR, Cheema MS, Ausió J, Gowen BE. Spermatogenesis in haploid males of the jewel wasp Nasonia vitripennis. Sci Rep 2019; 9:12194. [PMID: 31434920 PMCID: PMC6704150 DOI: 10.1038/s41598-019-48332-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/29/2019] [Indexed: 01/11/2023] Open
Abstract
Males of hymenopteran insects, which include ants, bees and wasps, develop as haploids from unfertilized eggs. In order to accommodate their lack of homologous chromosome pairs, some hymenopterans such as the honeybee have been shown to produce haploid sperm through an abortive meiosis. We employed microscopic approaches to visualize landmark aspects of spermatogenesis in the jewel wasp Nasonia vitripennis, a model for hymenopteran reproduction and development. Our work demonstrates that N. vitripennis, like other examined hymenopterans, exhibits characteristics indicative of an abortive meiosis, including slight enlargement of spermatocytes preceding meiotic initiation. However, we saw no evidence of cytoplasmic buds containing centrioles that are produced from the first abortive meiotic division, which occurs in the honeybee. In contrast to other previously studied hymenopterans, N. vitripennis males produce sperm in bundles that vary widely from 16 to over 200, thus reflecting a range of cellular divisions. Our results highlight interesting variations in spermatogenesis among the hymenopteran insects, and together with previous studies, they suggest a pattern of progression from meiosis to a more mitotic state in producing sperm.
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Affiliation(s)
- Patrick M Ferree
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA.
| | - John C Aldrich
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Xueyuan A Jing
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Christopher T Norwood
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Mary R Van Schaick
- W. M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, 91711, USA
| | - Manjinder S Cheema
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W-3P6, Canada
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W-3P6, Canada
| | - Brent E Gowen
- Department of Biology, University of Victoria, Victoria, BC, V8W-3P6, Canada
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Li M, Bui M, Akbari OS. Embryo Microinjection and Transplantation Technique for Nasonia vitripennis Genome Manipulation. J Vis Exp 2017. [PMID: 29364231 PMCID: PMC5908372 DOI: 10.3791/56990] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The jewel wasp Nasonia vitripennis has emerged as an effective model system for the study of processes including sex determination, haplo-diploid sex determination, venom synthesis, and host-symbiont interactions, among others. A major limitation of working with this organism is the lack of effective protocols to perform directed genome modifications. An important part of genome modification is delivery of editing reagents, including CRISPR/Cas9 molecules, into embryos through microinjection. While microinjection is well established in many model organisms, this technique is particularly challenging to perform in N. vitripennis primarily due to its small embryo size, and the fact that embryonic development occurs entirely within a parasitized blowfly pupa. The following procedure overcomes these significant challenges while demonstrating a streamlined, visual procedure for effectively removing wasp embryos from parasitized host pupae, microinjecting them, and carefully transplanting them back into the host for continuation and completion of development. This protocol will strongly enhance the capability of research groups to perform advanced genome modifications in this organism.
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Affiliation(s)
- Ming Li
- Department of Entomology and Riverside Center of Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside; Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego
| | - Michelle Bui
- Department of Entomology and Riverside Center of Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside; Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego
| | - Omar S Akbari
- Department of Entomology and Riverside Center of Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside; Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego;
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Shirk PD, Furlong RB, Dolan A, Werren JH. Functional characterization of the transcriptional regulatory elements of three highly expressed constitutive genes in the jewel wasp, Nasonia vitripennis. INSECT MOLECULAR BIOLOGY 2017; 26:743-751. [PMID: 28753244 DOI: 10.1111/imb.12333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The jewel wasp, Nasonia vitripennis Ashmead (Hymenoptera: Pteromalidae), is an easily reared parasitoid that is providing an ever increasingly malleable model for examining the biology and genetics of Hymenoptera. Utilizing genomic and transcriptome resources, 5' upstream transcriptional regulatory sequences (TREs) from three highly expressed genes were identified and cloned. Criteria for TRE selection included the presence of an adjacent gene 5' of the translation initiation site. One gene was methylated whereas the other two were nonmethylated. Each TRE, heat-shock protein 70 (hsp70), activator of 90 kDa hsp ATPase protein 1 (hsp90A), and lipid storage droplet surface-binding protein 1 (lsdp) was linked with enhanced green fluorescent protein (EGFP) coding sequence and cloned into both pDP9e somatic and piggyBac germline transformation vectors. EGFP expression patterns under control of each TRE were compared with patterns of DsRed fluorescence produced from the transformation vector cassette. Functional activity of each TRE was observed in cultured Spodoptera frugiperda 9 (Sf9) cells and Drosophila melanogaster as well as in N. vitripennis embryos demonstrating that all three sequences had functional transcriptional regulatory activity in three different insect orders. Identification and functional characterization of these three TREs will provide critical and necessary resources for further genetic analyses of N. vitripennis, Hymenoptera and other insects.
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Affiliation(s)
- P D Shirk
- USDA-ARS Center for Medical Agricultural and Veterinary Entomology, Gainesville, FL, USA
| | - R B Furlong
- USDA-ARS Center for Medical Agricultural and Veterinary Entomology, Gainesville, FL, USA
| | - A Dolan
- Department of Biology, University of Rochester, Rochester, NY, USA
| | - J H Werren
- Department of Biology, University of Rochester, Rochester, NY, USA
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Wu C, Twort VG, Crowhurst RN, Newcomb RD, Buckley TR. Assembling large genomes: analysis of the stick insect (Clitarchus hookeri) genome reveals a high repeat content and sex-biased genes associated with reproduction. BMC Genomics 2017; 18:884. [PMID: 29145825 PMCID: PMC5691397 DOI: 10.1186/s12864-017-4245-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 10/31/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Stick insects (Phasmatodea) have a high incidence of parthenogenesis and other alternative reproductive strategies, yet the genetic basis of reproduction is poorly understood. Phasmatodea includes nearly 3000 species, yet only the genome of Timema cristinae has been published to date. Clitarchus hookeri is a geographical parthenogenetic stick insect distributed across New Zealand. Sexual reproduction dominates in northern habitats but is replaced by parthenogenesis in the south. Here, we present a de novo genome assembly of a female C. hookeri and use it to detect candidate genes associated with gamete production and development in females and males. We also explore the factors underlying large genome size in stick insects. RESULTS The C. hookeri genome assembly was 4.2 Gb, similar to the flow cytometry estimate, making it the second largest insect genome sequenced and assembled to date. Like the large genome of Locusta migratoria, the genome of C. hookeri is also highly repetitive and the predicted gene models are much longer than those from most other sequenced insect genomes, largely due to longer introns. Miniature inverted repeat transposable elements (MITEs), absent in the much smaller T. cristinae genome, is the most abundant repeat type in the C. hookeri genome assembly. Mapping RNA-Seq reads from female and male gonadal transcriptomes onto the genome assembly resulted in the identification of 39,940 gene loci, 15.8% and 37.6% of which showed female-biased and male-biased expression, respectively. The genes that were over-expressed in females were mostly associated with molecular transportation, developmental process, oocyte growth and reproductive process; whereas, the male-biased genes were enriched in rhythmic process, molecular transducer activity and synapse. Several genes involved in the juvenile hormone synthesis pathway were also identified. CONCLUSIONS The evolution of large insect genomes such as L. migratoria and C. hookeri genomes is most likely due to the accumulation of repetitive regions and intron elongation. MITEs contributed significantly to the growth of C. hookeri genome size yet are surprisingly absent from the T. cristinae genome. Sex-biased genes identified from gonadal tissues, including genes involved in juvenile hormone synthesis, provide interesting candidates for the further study of flexible reproduction in stick insects.
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Affiliation(s)
- Chen Wu
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Landcare Research, Auckland, New Zealand
- New Zealand Institute for Plant & Food Research Ltd, Auckland, New Zealand
| | - Victoria G. Twort
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Landcare Research, Auckland, New Zealand
- Department of Biology, Lund University, Lund, Sweden
| | - Ross N. Crowhurst
- New Zealand Institute for Plant & Food Research Ltd, Auckland, New Zealand
| | - Richard D. Newcomb
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- New Zealand Institute for Plant & Food Research Ltd, Auckland, New Zealand
| | - Thomas R. Buckley
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
- Landcare Research, Auckland, New Zealand
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Unique sequence organization and small RNA expression of a "selfish" B chromosome. Chromosoma 2017; 126:753-768. [PMID: 28780664 DOI: 10.1007/s00412-017-0641-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 10/19/2022]
Abstract
B chromosomes are found in numerous plants and animals. These nonessential, supernumerary chromosomes are often composed primarily of noncoding DNA repeats similar to those found within transcriptionally "silenced" heterochromatin. In order to persist within their resident genomes, many B chromosomes exhibit exceptional cellular behaviors, including asymmetric segregation into gametes and induction of genome elimination during early development. An important goal in understanding these behaviors is to identify unique B chromosome sequences and characterize their transcriptional contributions. We investigated these properties by examining a paternally transmitted B chromosome known as paternal sex ratio (PSR), which is present in natural populations of the jewel wasp Nasonia vitripennis. To facilitate its own transmission, PSR severely biases the sex ratio by disrupting early chromatin remodeling processes. Through cytological mapping and other approaches, we identified multiple DNA repeats unique to PSR, as well as those found on the A chromosomes, suggesting that PSR arose through a merger of sequences from both within and outside the N. vitripennis genome. The majority of PSR-specific repeats are interspersed among each other across PSR's long arm, in contrast with the distinct "blocks" observed in other organisms' heterochromatin. Through transcriptional profiling, we identified a subset of repeat-associated, small RNAs expressed by PSR, most of which map to a single PSR-specific repeat. These RNAs are expressed at much higher levels than those arising from A chromosome-linked repeats, suggesting that in addition to its sequence organization, PSR's transcriptional properties differ substantially from the pericentromeric regions of the normal chromosomes.
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Li M, Au LYC, Douglah D, Chong A, White BJ, Ferree PM, Akbari OS. Generation of heritable germline mutations in the jewel wasp Nasonia vitripennis using CRISPR/Cas9. Sci Rep 2017; 7:901. [PMID: 28424460 PMCID: PMC5430486 DOI: 10.1038/s41598-017-00990-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/17/2017] [Indexed: 01/01/2023] Open
Abstract
The revolutionary RNA-guided endonuclease CRISPR/Cas9 system has proven to be a powerful tool for gene editing in a plethora of organisms. Here, utilizing this system we developed an efficient protocol for the generation of heritable germline mutations in the parasitoid jewel wasp, Nasonia vitripennis, a rising insect model organism for the study of evolution, development of axis pattern formation, venom production, haplo-diploid sex determination, and host–symbiont interactions. To establish CRISPR-directed gene editing in N. vitripennis, we targeted a conserved eye pigmentation gene cinnabar, generating several independent heritable germline mutations in this gene. Briefly, to generate these mutants, we developed a protocol to efficiently collect N. vitripennis eggs from a parasitized flesh fly pupa, Sarcophaga bullata, inject these eggs with Cas9/guide RNA mixtures, and transfer injected eggs back into the host to continue development. We also describe a flow for screening mutants and establishing stable mutant strains through genetic crosses. Overall, our results demonstrate that the CRISPR/Cas9 system is a powerful tool for genome manipulation in N. vitripennis, with strong potential for expansion to target critical genes, thus allowing for the investigation of several important biological phenomena in this organism.
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Affiliation(s)
- Ming Li
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Lauren Yun Cook Au
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 Mills Avenue, Claremont, CA, 91711, USA
| | - Deema Douglah
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 Mills Avenue, Claremont, CA, 91711, USA
| | - Abigail Chong
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Bradley J White
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, 92521, USA
| | - Patrick M Ferree
- W.M. Keck Science Department, Claremont McKenna, Pitzer and Scripps Colleges, 925 Mills Avenue, Claremont, CA, 91711, USA.
| | - Omar S Akbari
- Department of Entomology and Riverside Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, 92521, USA.
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