1
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Devos L, Agnès F, Edouard J, Simon V, Legendre L, El Khallouki N, Barbachou S, Sohm F, Rétaux S. Eye morphogenesis in the blind Mexican cavefish. Biol Open 2021; 10:bio059031. [PMID: 34590124 PMCID: PMC8565469 DOI: 10.1242/bio.059031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 01/13/2023] Open
Abstract
The morphogenesis of the vertebrate eye consists of a complex choreography of cell movements, tightly coupled to axial regionalization and cell type specification processes. Disturbances in these events can lead to developmental defects and blindness. Here, we have deciphered the sequence of defective events leading to coloboma in the embryonic eye of the blind cavefish of the species Astyanax mexicanus. Using comparative live imaging on targeted enhancer-trap Zic1:hsp70:GFP reporter lines of both the normal, river-dwelling morph and the cave morph of the species, we identified defects in migratory cell behaviours during evagination that participate in the reduced optic vesicle size in cavefish, without proliferation defect. Further, impaired optic cup invagination shifts the relative position of the lens and contributes to coloboma in cavefish. Based on these results, we propose a developmental scenario to explain the cavefish phenotype and discuss developmental constraints to morphological evolution. The cavefish eye appears as an outstanding natural mutant model to study molecular and cellular processes involved in optic region morphogenesis.
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Affiliation(s)
- Lucie Devos
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
| | - François Agnès
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
| | - Joanne Edouard
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Victor Simon
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Laurent Legendre
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Naima El Khallouki
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Sosthène Barbachou
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Frédéric Sohm
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
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2
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Stage-Specific Effects of Ionizing Radiation during Early Development. Int J Mol Sci 2020; 21:ijms21113975. [PMID: 32492918 PMCID: PMC7312565 DOI: 10.3390/ijms21113975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/28/2020] [Accepted: 05/30/2020] [Indexed: 02/07/2023] Open
Abstract
Early embryonic cells are sensitive to genotoxic stressors such as ionizing radiation. However, sensitivity to these stressors varies depending on the embryonic stage. Recently, the sensitivity and response to ionizing radiation were found to differ during the preimplantation period. The cellular and molecular mechanisms underlying the change during this period are beginning to be elucidated. In this review, we focus on the changes in radio-sensitivity and responses to ionizing radiation during the early developmental stages of the preimplantation (before gastrulation) period in mammals, Xenopus, and fish. Furthermore, we discuss the underlying cellular and molecular mechanisms and the similarities and differences between species.
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3
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Li W, Zhang Y, Han B, Li L, Li M, Lu X, Chen C, Lu M, Zhang Y, Jia X, Zhu Z, Tong X, Zhang B. One-step efficient generation of dual-function conditional knockout and geno-tagging alleles in zebrafish. eLife 2019; 8:48081. [PMID: 31663848 PMCID: PMC6845224 DOI: 10.7554/elife.48081] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022] Open
Abstract
CRISPR/Cas systems are widely used to knock out genes by inducing indel mutations, which are prone to genetic compensation. Complex genome modifications such as knockin (KI) might bypass compensation, though difficult to practice due to low efficiency. Moreover, no ‘two-in-one’ KI strategy combining conditional knockout (CKO) with fluorescent gene-labeling or further allele-labeling has been reported. Here, we developed a dual-cassette-donor strategy and achieved one-step and efficient generation of dual-function KI alleles at tbx5a and kctd10 loci in zebrafish via targeted insertion. These alleles display fluorescent gene-tagging and CKO effects before and after Cre induction, respectively. By introducing a second fluorescent reporter, geno-tagging effects were achieved at tbx5a and sox10 loci, exhibiting CKO coupled with fluorescent reporter switch upon Cre induction, enabling tracing of three distinct genotypes. We found that LiCl purification of gRNA is critical for highly efficient KI, and preselection of founders allows the efficient germline recovery of KI events.
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Affiliation(s)
- Wenyuan Li
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Yage Zhang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Bingzhou Han
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Lianyan Li
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Muhang Li
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Xiaochan Lu
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Cheng Chen
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Mengjia Lu
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Yujie Zhang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Xuefeng Jia
- Gcrispr (Tianjin) Genetic Technology, Tianjin, China
| | - Zuoyan Zhu
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Xiangjun Tong
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
| | - Bo Zhang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, Peking University Genome Editing Research Center, College of Life Sciences, Peking University, Beijing, China
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4
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Prevalence of Mutation-Prone Microhomology-Mediated End Joining in a Chordate Lacking the c-NHEJ DNA Repair Pathway. Curr Biol 2018; 28:3337-3341.e4. [PMID: 30293719 DOI: 10.1016/j.cub.2018.08.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/18/2018] [Accepted: 08/21/2018] [Indexed: 12/20/2022]
Abstract
Classical non-homologous end joining (c-NHEJ), a fundamental pathway that repairs double-strand breaks in DNA, is almost universal in eukaryotes and involves multiple proteins highly conserved from yeast to human [1]. The genes encoding these proteins were not detected in the genome of Oikopleura dioica, a new model system of tunicate larvaceans known for its very compact and highly rearranged genome [2-4]. After showing their absence in the genomes of six other larvacean species, the present study examined how O. dioica oocytes and embryos repair double-strand DNA breaks (DSBs), using two approaches: the injection of linearized plasmids, which resulted in their rapid end joining, and a newly established CRISPR Cas9 technique. In both cases, end joining merged short microhomologous sequences surrounding the break (mainly 4 bp long), thus inducing deletions larger than for the tunicate ascidian Ciona intestinalis and human cells. A relatively high frequency of nucleotide insertions was also observed. Finally, a survey of genomic indels supports the involvement of microhomology-mediated repair in natural conditions. Overall, O. dioica repairs DSBs as other organisms do when their c-NHEJ pathway is experimentally rendered deficient, using another mode of end joining with the same effect as alternative NHEJ (a-NHEJ) or microhomology-mediated end joining (MMEJ) [5-7]. We discuss how the exceptional loss of c-NHEJ and its replacement by a more mutation-prone mechanism may have contributed to reshaping this genome and even been advantageous under pressure for genome compaction.
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5
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Kesavan G, Hammer J, Hans S, Brand M. Targeted knock-in of CreER T2 in zebrafish using CRISPR/Cas9. Cell Tissue Res 2018; 372:41-50. [DOI: 10.1007/s00441-018-2798-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/16/2018] [Indexed: 12/31/2022]
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6
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Tálas A, Kulcsár PI, Weinhardt N, Borsy A, Tóth E, Szebényi K, Krausz SL, Huszár K, Vida I, Sturm Á, Gordos B, Hoffmann OI, Bencsura P, Nyeste A, Ligeti Z, Fodor E, Welker E. A convenient method to pre-screen candidate guide RNAs for CRISPR/Cas9 gene editing by NHEJ-mediated integration of a 'self-cleaving' GFP-expression plasmid. DNA Res 2017; 24:609-621. [PMID: 28679166 PMCID: PMC5726473 DOI: 10.1093/dnares/dsx029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 06/07/2017] [Indexed: 12/20/2022] Open
Abstract
The efficacies of guide RNAs (gRNAs), the short RNA molecules that bind to and determine the sequence specificity of the Streptococcus pyogenes Cas9 nuclease, to mediate DNA cleavage vary dramatically. Thus, the selection of appropriate target sites, and hence spacer sequence, is critical for most applications. Here, we describe a simple, unparalleled method for experimentally pre-testing the efficiencies of various gRNAs targeting a gene. The method explores NHEJ-cloning, genomic integration of a GFP-expressing plasmid without homologous arms and linearized in-cell. The use of 'self-cleaving' GFP-plasmids containing universal gRNAs and corresponding targets alleviates cloning burdens when this method is applied. These universal gRNAs mediate efficient plasmid cleavage and are designed to avoid genomic targets in several model species. The method combines the advantages of the straightforward FACS detection provided by applying fluorescent reporter systems and of the PCR-based approaches being capable of testing targets in their genomic context, without necessitating any extra cloning steps. Additionally, we show that NHEJ-cloning can also be used in mammalian cells for targeted integration of donor plasmids up to 10 kb in size, with up to 30% efficiency, without any selection or enrichment.
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Affiliation(s)
- András Tálas
- School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Péter István Kulcsár
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
- University of Szeged, Szeged, Hungary
| | - Nóra Weinhardt
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
- University of Szeged, Szeged, Hungary
| | - Adrienn Borsy
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Eszter Tóth
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Kornélia Szebényi
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Sarah Laura Krausz
- School of Ph.D. Studies, Semmelweis University, Budapest, Hungary
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Krisztina Huszár
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - István Vida
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Organic Chemistry, Eötvös Loránd University, Budapest, Hungary
| | - Ádám Sturm
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Bianka Gordos
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Orsolya Ivett Hoffmann
- Animal Biotechnology Section, Ruminant Genome Biology Group, NARIC Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Petra Bencsura
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Antal Nyeste
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Zoltán Ligeti
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
| | - Elfrieda Fodor
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Ervin Welker
- Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
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7
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Kesavan G, Chekuru A, Machate A, Brand M. CRISPR/Cas9-Mediated Zebrafish Knock-in as a Novel Strategy to Study Midbrain-Hindbrain Boundary Development. Front Neuroanat 2017; 11:52. [PMID: 28713249 PMCID: PMC5492657 DOI: 10.3389/fnana.2017.00052] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/19/2017] [Indexed: 11/13/2022] Open
Abstract
The midbrain-hindbrain boundary (MHB) acts as an organizer and controls the fate of neighboring cells to develop into either mesencephalic (midbrain) or metencephalic (hindbrain) cells by secreting signaling molecules like Wnt1 and Fgf8. The zebrafish is an excellent vertebrate model for studying MHB development due to the ease of gene manipulation and the possibility of following cellular dynamics and morphogenetic processes using live imaging. Currently, only very few reporter and/or Cre-driver lines are available to study gene expression at the MHB, hampering the understanding of MHB development, and traditional transgenic technologies using promoter/enhancer fragments or bacterial artificial chromosome (BAC)-mediated transgenesis often do not faithfully recapitulate endogenous expression patterns. In contrast, CRISPR/Cas9-mediated genome editing technology now provides a great opportunity to efficiently knock-in or knock-out genes. We have generated four CRISPR/Cas9-based knock-in fluorescent reporter lines for two crucial genes involved in MHB development, namely otx2 and pax2a. The coding sequences of the reporters were knocked-in upstream of the corresponding ATG and are, thus, under the control of the endogenous promoter/enhancer elements. Interestingly, this strategy does not disturb endogenous gene expression. Using the fast maturing fluorescent protein reporter, Venus, enabled us to follow MHB development using cell tracking and live imaging. In addition, we show that these reporter lines label various neuronal and glial cell types in the adult zebrafish brain, making them highly suitable for investigating embryonic and adult midbrain, hindbrain, and MHB development.
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Affiliation(s)
- Gokul Kesavan
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden, Technische Universität DresdenDresden, Germany
| | - Avinash Chekuru
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden, Technische Universität DresdenDresden, Germany
| | - Anja Machate
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden, Technische Universität DresdenDresden, Germany
| | - Michael Brand
- Biotechnology Center and DFG-Research Center for Regenerative Therapies Dresden, Technische Universität DresdenDresden, Germany
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8
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Albadri S, Del Bene F, Revenu C. Genome editing using CRISPR/Cas9-based knock-in approaches in zebrafish. Methods 2017; 121-122:77-85. [PMID: 28300641 DOI: 10.1016/j.ymeth.2017.03.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/13/2017] [Accepted: 03/03/2017] [Indexed: 12/19/2022] Open
Abstract
With its variety of applications, the CRISPR/Cas9 genome editing technology has been rapidly evolving in the last few years. In the zebrafish community, knock-out reports are constantly increasing but insertion studies have been so far more challenging. With this review, we aim at giving an overview of the homologous directed repair (HDR)-based knock-in generation in zebrafish. We address the critical points and limitations of the procedure such as cutting efficiency of the chosen single guide RNA, use of cas9 mRNA or Cas9 protein, homology arm size etc. but also ways to circumvent encountered issues with HDR insertions by the development of non-homologous dependent strategies. While imprecise, these homology-independent mechanisms based on non-homologous-end-joining (NHEJ) repair have been employed in zebrafish to generate reporter lines or to accurately edit an open reading frame by the use of intron-targeting modifications. Therefore, with higher efficiency and insertion rate, NHEJ-based knock-in seems to be a promising approach to target endogenous loci and to circumvent the limitations of HDR whenever it is possible and appropriate. In this perspective, we propose new strategies to generate cDNA edited or tagged insertions, which once established will constitute a new and versatile toolbox for CRISPR/Cas9-based knock-ins in zebrafish.
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Affiliation(s)
- Shahad Albadri
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, 75248 Paris Cedex 05, France
| | - Filippo Del Bene
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, 75248 Paris Cedex 05, France.
| | - Céline Revenu
- Institut Curie, PSL Research University, INSERM U934, CNRS UMR3215, 75248 Paris Cedex 05, France
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9
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Intron-based genomic editing: a highly efficient method for generating knockin zebrafish. Oncotarget 2016; 6:17891-4. [PMID: 26143640 PMCID: PMC4627223 DOI: 10.18632/oncotarget.4547] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/06/2015] [Indexed: 01/17/2023] Open
Abstract
The TALEN and CRISPR/Cas9 nuclease systems have been extensively utilized in genomic engineering of model organisms. In zebrafish, the nuclease systems have been successfully applied in generating loss-of–function knockout lines. However, genome-specific knockin techniques in zebrafish are still at the beginning. In this perspective, we briefly summarize the recent progresses on knockin approaches in zebrafish with a special focus on the newly developed intron-based knockin method.
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10
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Parant JM, Yeh JRJ. Approaches to Inactivate Genes in Zebrafish. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 916:61-86. [PMID: 27165349 DOI: 10.1007/978-3-319-30654-4_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Animal models of tumor initiation and tumor progression are essential components toward understanding cancer and designing/validating future therapies. Zebrafish is a powerful model for studying tumorigenesis and has been successfully exploited in drug discovery. According to the zebrafish reference genome, 82 % of disease-associated genes in the Online Mendelian Inheritance in Man (OMIM) database have clear zebrafish orthologues. Using a variety of large-scale random mutagenesis methods developed to date, zebrafish can provide a unique opportunity to identify gene mutations that may be associated with cancer predisposition. On the other hand, newer technologies enabling targeted mutagenesis can facilitate reverse cancer genetic studies and open the door for complex genetic analysis of tumorigenesis. In this chapter, we will describe the various technologies for conducting genome editing in zebrafish with special emphasis on the approaches to inactivate genes.
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Affiliation(s)
- John M Parant
- Department of Pharmacology and Toxicology, UAB Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Birmingham, AL, 35294, USA.
| | - Jing-Ruey Joanna Yeh
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA, 02129, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.
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11
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Wyatt C, Bartoszek EM, Yaksi E. Methods for studying the zebrafish brain: past, present and future. Eur J Neurosci 2015; 42:1746-63. [PMID: 25900095 DOI: 10.1111/ejn.12932] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 01/16/2023]
Abstract
The zebrafish (Danio rerio) is one of the most promising new model organisms. The increasing popularity of this amazing small vertebrate is evident from the exponentially growing numbers of research articles, funded projects and new discoveries associated with the use of zebrafish for studying development, brain function, human diseases and screening for new drugs. Thanks to the development of novel technologies, the range of zebrafish research is constantly expanding with new tools synergistically enhancing traditional techniques. In this review we will highlight the past and present techniques which have made, and continue to make, zebrafish an attractive model organism for various fields of biology, with a specific focus on neuroscience.
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Affiliation(s)
- Cameron Wyatt
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium
| | - Ewelina M Bartoszek
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Emre Yaksi
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium.,KU Leuven, Leuven, Belgium.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
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12
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Auer TO, Del Bene F. CRISPR/Cas9 and TALEN-mediated knock-in approaches in zebrafish. Methods 2014; 69:142-50. [DOI: 10.1016/j.ymeth.2014.03.027] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 03/07/2014] [Accepted: 03/24/2014] [Indexed: 12/26/2022] Open
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13
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Love DR, Lan CC, Dodd A, Shelling AN, McNabb WC, Ferguson LR. Modeling inflammatory bowel disease: the zebrafish as a way forward. Expert Rev Mol Diagn 2014; 7:177-93. [PMID: 17331065 DOI: 10.1586/14737159.7.2.177] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The zebrafish has proved to be an informative model of vertebrate development and, more recently, an emerging model of human disease. The realization of the full potential of the zebrafish as a disease model lies in two interdependent areas. The first is an appreciation that the often overlooked strength of this species lies in allowing the design of experiments that address the interplay of genetics and the environment in a manipulable manner. The second is in the application and further development of gene targeting approaches. These twin features will be addressed in this review in the context of modeling inflammatory bowel disease.
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Affiliation(s)
- Donald R Love
- University of Auckland, School of Biological Sciences, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand.
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14
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Abstract
Genome editing using the Cas9 endonuclease of Streptococcus pyogenes has demonstrated unprecedented efficacy and facility in a wide variety of biological systems. In zebrafish, specifically, studies have shown that Cas9 can be directed to user-defined genomic target sites via synthetic guide RNAs, enabling random or homology-directed sequence alterations, long-range chromosomal deletions, simultaneous disruption of multiple genes, and targeted integration of several kilobases of DNA. Altogether, these methods are opening new doors for the engineering of knock-outs, conditional alleles, tagged proteins, reporter lines, and disease models. In addition, the ease and high efficiency of generating Cas9-mediated gene knock-outs provides great promise for high-throughput functional genomics studies in zebrafish. In this chapter, we briefly review the origin of CRISPR/Cas technology and discuss current Cas9-based genome-editing applications in zebrafish with particular emphasis on their designs and implementations.
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Affiliation(s)
- Andrew P W Gonzales
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Jing-Ruey Joanna Yeh
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
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15
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Auer TO, Duroure K, De Cian A, Concordet JP, Del Bene F. Highly efficient CRISPR/Cas9-mediated knock-in in zebrafish by homology-independent DNA repair. Genome Res 2014; 24:142-53. [PMID: 24179142 PMCID: PMC3875856 DOI: 10.1101/gr.161638.113] [Citation(s) in RCA: 450] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/28/2013] [Indexed: 01/25/2023]
Abstract
Sequence-specific nucleases like TALENs and the CRISPR/Cas9 system have greatly expanded the genome editing possibilities in model organisms such as zebrafish. Both systems have recently been used to create knock-out alleles with great efficiency, and TALENs have also been successfully employed in knock-in of DNA cassettes at defined loci via homologous recombination (HR). Here we report CRISPR/Cas9-mediated knock-in of DNA cassettes into the zebrafish genome at a very high rate by homology-independent double-strand break (DSB) repair pathways. After co-injection of a donor plasmid with a short guide RNA (sgRNA) and Cas9 nuclease mRNA, concurrent cleavage of donor plasmid DNA and the selected chromosomal integration site resulted in efficient targeted integration of donor DNA. We successfully employed this approach to convert eGFP into Gal4 transgenic lines, and the same plasmids and sgRNAs can be applied in any species where eGFP lines were generated as part of enhancer and gene trap screens. In addition, we show the possibility of easily targeting DNA integration at endogenous loci, thus greatly facilitating the creation of reporter and loss-of-function alleles. Due to its simplicity, flexibility, and very high efficiency, our method greatly expands the repertoire for genome editing in zebrafish and can be readily adapted to many other organisms.
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Affiliation(s)
- Thomas O. Auer
- Institut Curie, Centre de Recherche, Paris F-75248, France
- CNRS UMR 3215, Paris F-75248, France
- INSERM U934, F-75248 Paris, France
- Centre for Organismal Studies Heidelberg, University of Heidelberg, 69120 Heidelberg, Germany
| | - Karine Duroure
- Institut Curie, Centre de Recherche, Paris F-75248, France
- CNRS UMR 3215, Paris F-75248, France
- INSERM U934, F-75248 Paris, France
| | - Anne De Cian
- Muséum National d'Histoire Naturelle, Paris F-75231, France
- CNRS UMR 7196, Paris F-75231, France
- INSERM U565, Paris F-75231, France
| | - Jean-Paul Concordet
- Muséum National d'Histoire Naturelle, Paris F-75231, France
- CNRS UMR 7196, Paris F-75231, France
- INSERM U565, Paris F-75231, France
| | - Filippo Del Bene
- Institut Curie, Centre de Recherche, Paris F-75248, France
- CNRS UMR 3215, Paris F-75248, France
- INSERM U934, F-75248 Paris, France
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16
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Pillay LM, Selland LG, Fleisch VC, Leighton PLA, Cheng CS, Famulski JK, Ritzel RG, March LD, Wang H, Allison WT, Waskiewicz AJ. Evaluating the mutagenic activity of targeted endonucleases containing a Sharkey FokI cleavage domain variant in zebrafish. Zebrafish 2013; 10:353-64. [PMID: 23781947 DOI: 10.1089/zeb.2012.0832] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Synthetic targeted endonucleases such as zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs) have recently emerged as powerful tools for targeted mutagenesis, especially in organisms that are not amenable to embryonic stem cell manipulation. Both ZFNs and TALENs consist of DNA-binding arrays that are fused to the nonspecific FokI nuclease domain. In an effort to improve targeted endonuclease mutagenesis efficiency, we enhanced their catalytic activity using the Sharkey FokI nuclease domain variant. All constructs tested display increased DNA cleavage activity in vitro. We demonstrate that one out of four ZFN arrays containing the Sharkey FokI variant exhibits a dramatic increase in mutagenesis frequency in vivo in zebrafish. The other three ZFNs exhibit no significant alteration of activity in vivo. Conversely, we demonstrate that TALENs containing the Sharkey FokI variant exhibit absent or severely reduced in vivo mutagenic activity in zebrafish. Notably, Sharkey ZFNs and TALENs do not generate increased toxicity-related defects or mortality. Our results present Sharkey ZFNs as an effective alternative to conventional ZFNs, but advise against the use of Sharkey TALENs.
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Affiliation(s)
- Laura M Pillay
- Department of Biological Sciences, University of Alberta , Edmonton, Canada
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17
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Kienzler A, Bony S, Devaux A. DNA repair activity in fish and interest in ecotoxicology: a review. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 134-135:47-56. [PMID: 23571068 DOI: 10.1016/j.aquatox.2013.03.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 03/06/2013] [Accepted: 03/06/2013] [Indexed: 05/20/2023]
Abstract
The knowledge of DNA repair in a target species is of first importance as it is the primary line of defense against genotoxicants, and a better knowledge of DNA repair capacity in fish could help to interpret genotoxicity data and/or assist in the choice of target species, developmental stage and tissues to focus on, both for environmental biomonitoring studies and DNA repair testing. This review focuses in a first part on what is presently known on a mechanistic basis, about the various DNA repair systems in fish, in vivo and in established cell lines. Data on base excision repair (BER), direct reversal with O⁶-alkylguanine transferase and double strand breaks repair, although rather scarce, are being reviewed, as well as nucleotide excision repair (NER) and photoreactivation repair (PER), which are by far the most studied repair mechanisms in fish. Most of these repair mechanisms seem to be strongly species and tissue dependent; they also depend on the developmental stage of the organisms. BER is efficient in vivo, although no data has been found on in vitro models. NER activity is quite low or even inexistent depending on the studies; however this lack is partly compensated by a strong PER activity, especially in early developmental stage. In a second part, a survey of the ecotoxicological studies integrating DNA repair as a parameter responding to single or mixture of contaminant is realized. Three main approaches are being used: the measurement of DNA repair gene expression after exposure, although it has not yet been clearly established whether gene expression is indicative of repair capacity; the monitoring of DNA damage removal by following DNA repair kinetics; and the modulation of DNA repair activity following exposure in situ, in order to assess the impact of exposure history on DNA repair capacity. Since all DNA repair processes are possible targets for environmental pollutants, we can also wonder at which extent such a modulation of repair capacities in fish could be the base for the development of new biomarkers of genotoxicity. Knowing the importance of the germ cell DNA integrity in the reproductive success of aquatic organisms, the DNA repair capacity of such cells deserve to be more studied, as well as DNA repair capacities of established fish cell lines. The limited amount of available data, which shows low/slow DNA repair capacities of fish cell lines compared with mammalian cell lines, concerned mainly the NER system; thus this point merits to be explored more deeply. Additionally, since some of the DNA repair systems appear more efficient in embryo larval stages, it would be of interest to consider embryonic cell lineages more closely.
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Affiliation(s)
- Aude Kienzler
- UMR LEHNA 5023, Université de Lyon, F-69518 Vaulx-en-Velin, France.
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18
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Pei DS, Strauss PR. Zebrafish as a model system to study DNA damage and repair. Mutat Res 2013; 743-744:151-159. [PMID: 23211879 DOI: 10.1016/j.mrfmmm.2012.10.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/19/2012] [Accepted: 10/23/2012] [Indexed: 05/20/2023]
Abstract
Zebrafish (Danio rerio) have become a popular vertebrate model to study embryological development, because of unique advantages not found in other model systems. Zebrafish share many gene functions with other vertebrates including humans, making zebrafish a useful system for studying cancer etiology. However, systematic studies of DNA damage and repair pathways using adult or embryonic zebrafish have not been extensively reported. The zebrafish genome contains nearly all the genes involved in different DNA repair pathways in eukaryotes, including direct reversal (DR), mismatch repair (MMR) nucleotide excision repair (NER), base excision repair (BER), homologous recombination (HR), non-homologous end joining (NHEJ) and translesion synthesis (TLS). It also includes the genes of the p53-mediated damage recognition pathway. Therefore, zebrafish provide an ideal model for gaining fundamental insights into mechanisms of DNA damage and repair, especially during embryological development. This review introduces recent work on different DNA damage and repair studies in zebrafish, with special emphasis on the role of BER in zebrafish early embryological development. AP endonuclease 1 (Apex1), a critical protein in the BER pathway, not only regulates BER but also controls cyclic AMP response binding protein (Creb1), which itself regulates ∼25% of eukaryotic coding sequences. In addition, Apex1 indirectly regulates levels of p53. As these findings also occur in murine B cells, they illustrate the usefulness of the zebrafish system in elucidating fundamental mechanisms.
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Affiliation(s)
- De-Sheng Pei
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122, China; Department of Biology, Northeastern University, Boston, MA 02115, USA.
| | - Phyllis R Strauss
- Department of Biology, Northeastern University, Boston, MA 02115, USA.
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19
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Snider AC, Leong D, Wang QT, Wysocka J, Yao MWM, Scott MP. The chromatin remodeling factor Chd1l is required in the preimplantation embryo. Biol Open 2012; 2:121-31. [PMID: 23429299 PMCID: PMC3575647 DOI: 10.1242/bio.20122949] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 10/17/2012] [Indexed: 01/07/2023] Open
Abstract
During preimplantation development, the embryo must establish totipotency and enact the earliest differentiation choices, processes that involve extensive chromatin modification. To identify novel developmental regulators, we screened for genes that are preferentially transcribed in the pluripotent inner cell mass (ICM) of the mouse blastocyst. Genes that encode chromatin remodeling factors were prominently represented in the ICM, including Chd1l, a member of the Snf2 gene family. Chd1l is developmentally regulated and expressed in embryonic stem (ES) cells, but its role in development has not been investigated. Here we show that inhibiting Chd1l protein production by microinjection of antisense morpholinos causes arrest prior to the blastocyst stage. Despite this important function in vivo, Chd1l is non-essential for cultured ES cell survival, pluripotency, or differentiation, suggesting that Chd1l is vital for events in embryos that are distinct from events in ES cells. Our data reveal a novel role for the chromatin remodeling factor Chd1l in the earliest cell divisions of mammalian development.
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Affiliation(s)
- Alyssa C Snider
- Departments of Developmental Biology, Genetics, and Bioengineering, University School of Medicine , Stanford, CA 94305-5101 , USA
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20
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Liu J, Gong L, Chang C, Liu C, Peng J, Chen J. Development of novel visual-plus quantitative analysis systems for studying DNA double-strand break repairs in zebrafish. J Genet Genomics 2012; 39:489-502. [PMID: 23021549 DOI: 10.1016/j.jgg.2012.07.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/26/2012] [Accepted: 07/18/2012] [Indexed: 01/17/2023]
Abstract
The use of reporter systems to analyze DNA double-strand break (DSB) repairs, based on the enhanced green fluorescent protein (EGFP) and meganuclease such as I-Sce I, is usually carried out with cell lines. In this study, we developed three visual-plus quantitative assay systems for homologous recombination (HR), non-homologous end joining (NHEJ) and single-strand annealing (SSA) DSB repair pathways at the organismal level in zebrafish embryos. To initiate DNA DSB repair, we used two I-Sce I recognition sites in opposite orientation rather than the usual single site. The NHEJ, HR and SSA repair pathways were separately triggered by the injection of three corresponding I-Sce I-cut constructions, and the repair of DNA lesion caused by I-Sce I could be tracked by EGFP expression in the embryos. Apart from monitoring the intensity of green fluorescence, the repair frequencies could also be precisely measured by quantitative real-time polymerase chain reaction (qPCR). Analysis of DNA sequences at the DSB sites showed that NHEJ was predominant among these three repair pathways in zebrafish embryos. Furthermore, while HR and SSA reporter systems could be effectively decreased by the knockdown of rad51 and rad52, respectively, NHEJ could only be impaired by the knockdown of ligaseIV (lig4) when the NHEJ construct was cut by I-Sce I in vivo. More interestingly, blocking NHEJ with lig4-MO increased the frequency of HR, but decreased the frequency of SSA. Our studies demonstrate that the major mechanisms used to repair DNA DSBs are conserved from zebrafish to mammal, and zebrafish provides an excellent model for studying and manipulating DNA DSB repair at the organismal level.
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Affiliation(s)
- Jingang Liu
- College of Life Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, China
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21
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Huang P, Zhu Z, Lin S, Zhang B. Reverse genetic approaches in zebrafish. J Genet Genomics 2012; 39:421-33. [PMID: 23021542 DOI: 10.1016/j.jgg.2012.07.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 07/03/2012] [Accepted: 07/07/2012] [Indexed: 12/14/2022]
Abstract
Zebrafish (Danio rerio) is a well-established vertebrate animal model. A comprehensive collection of reverse genetics tools has been developed for studying gene function in this useful organism. Morpholino is the most widely used reagent to knock down target gene expression post-transcriptionally. For a long time, targeted genome modification has been heavily relied on large-scale traditional forward genetic screens, such as ENU (N-ethyl-N-nitrosourea) mutagenesis derived TILLING (Targeting Induced Local Lesions IN Genomes) strategy and pseudo-typed retrovirus mediated insertional mutagenesis. Recently, engineered endonucleases, including ZFNs (zinc finger nucleases) and TALENs (transcription activator-like effector nucleases), provide new and efficient strategies to directly generate site-specific indel mutations by inducing double strand breaks in target genes. Here we summarize the major reverse genetic approaches for loss-of-function studies used and emerging in zebrafish, including strategies based on genome-wide mutagenesis and methods for site-specific gene targeting. Future directions and expectations will also be discussed.
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Affiliation(s)
- Peng Huang
- Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education, College of Life Sciences, Peking University, Beijing, China
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22
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Caroll D, Zhang B. Primer and interviews: advances in targeted gene modification. Interview by Julie C. Kiefer. Dev Dyn 2012; 240:2688-96. [PMID: 22072577 DOI: 10.1002/dvdy.22780] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Gene targeting in mice, first reported 25 years ago, has led to monumental advances in the understanding of basic biology and human disease. The ability to employ a similarly straightforward method for gene manipulation in other experimental organisms would make their already significant contributions all the more powerful. Here, we briefly outline the strengths and weaknesses of reverse genetics techniques in non-murine model organisms, ending with a more detailed description of two that promise to bring targeted gene modification to the masses: zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs). Dana Caroll, a forefather of zinc finger technology, and Bo Zhang, among the first to introduce TALEN-targeted mutagenesis to zebrafish, discuss their experience with these techniques, and speculate about the future of the field.
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Affiliation(s)
- Dana Caroll
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA.
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23
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White TB, Lambowitz AM. The retrohoming of linear group II intron RNAs in Drosophila melanogaster occurs by both DNA ligase 4-dependent and -independent mechanisms. PLoS Genet 2012; 8:e1002534. [PMID: 22359518 PMCID: PMC3280974 DOI: 10.1371/journal.pgen.1002534] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/24/2011] [Indexed: 12/31/2022] Open
Abstract
Mobile group II introns are bacterial retrotransposons that are thought to have invaded early eukaryotes and evolved into introns and retroelements in higher organisms. In bacteria, group II introns typically retrohome via full reverse splicing of an excised intron lariat RNA into a DNA site, where it is reverse transcribed by the intron-encoded protein. Recently, we showed that linear group II intron RNAs, which can result from hydrolytic splicing or debranching of lariat RNAs, can retrohome in eukaryotes by performing only the first step of reverse splicing, ligating their 3' end to the downstream DNA exon. Reverse transcription then yields an intron cDNA, whose free end is linked to the upstream DNA exon by an error-prone process that yields junctions similar to those formed by non-homologous end joining (NHEJ). Here, by using Drosophila melanogaster NHEJ mutants, we show that linear intron RNA retrohoming occurs by major Lig4-dependent and minor Lig4-independent mechanisms, which appear to be related to classical and alternate NHEJ, respectively. The DNA repair polymerase θ plays a crucial role in both pathways. Surprisingly, however, mutations in Ku70, which functions in capping chromosome ends during NHEJ, have only moderate, possibly indirect effects, suggesting that both Lig4 and the alternate end-joining ligase act in some retrohoming events independently of Ku. Another potential Lig4-independent mechanism, reverse transcriptase template switching from the intron RNA to the upstream exon DNA, occurs in vitro, but gives junctions differing from the majority in vivo. Our results show that group II introns can utilize cellular NHEJ enzymes for retromobility in higher organisms, possibly exploiting mechanisms that contribute to retrotransposition and mitigate DNA damage by resident retrotransposons. Additionally, our results reveal novel activities of group II intron reverse transcriptases, with implications for retrohoming mechanisms and potential biotechnological applications.
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Affiliation(s)
- Travis B. White
- Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry and Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas, United States of America
| | - Alan M. Lambowitz
- Institute for Cellular and Molecular Biology, Department of Chemistry and Biochemistry and Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas, United States of America
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24
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McCammon JM, Doyon Y, Amacher SL. Inducing high rates of targeted mutagenesis in zebrafish using zinc finger nucleases (ZFNs). Methods Mol Biol 2011; 770:505-27. [PMID: 21805278 DOI: 10.1007/978-1-61779-210-6_20] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Animal models, including the zebrafish, without a reliable embryonic stem cell system are not easily amenable to targeted mutagenesis for studying gene function. Three recent publications have shown that zinc finger nucleases (ZFNs) have circumvented this shortcoming in zebrafish. Similar to restriction enzymes, ZFNs can introduce site-specific double-strand breaks (DSBs); moreover, they can be designed to recognize virtually any target sequence. Because the preferred DSB repair pathway in zebrafish embryos, non-homologous end joining, is error-prone, ZFNs can be used to create mutations in a gene of interest. Here we review the protocols for a yeast-based assay to detect effective ZFNs. Additionally, we detail the procedures for synthesis and injection of ZFN-encoding mRNA into zebrafish embryos, screening of injected embryos for induced mutations in the soma, and recovery of germline mutations.
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Affiliation(s)
- Jasmine M McCammon
- Department of Molecular and Cell Biology, Center for Integrative Genomics, University of California, Berkeley, CA, USA.
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25
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Leong IUS, Lai D, Lan CC, Johnson R, Love DR, Johnson R, Love DR. Targeted mutagenesis of zebrafish: Use of zinc finger nucleases. ACTA ACUST UNITED AC 2011; 93:249-55. [DOI: 10.1002/bdrc.20213] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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26
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Liao HK, Essner JJ. Use of RecA fusion proteins to induce genomic modifications in zebrafish. Nucleic Acids Res 2011; 39:4166-79. [PMID: 21266475 PMCID: PMC3105420 DOI: 10.1093/nar/gkq1363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The bacterial recombinase RecA forms a nucleic acid-protein filament on single-stranded (ss) DNA during the repair of double-strand breaks (DSBs) that efficiently undergoes a homology search and engages in pairing with the complementary DNA sequence. We utilized the pairing activity of RecA–DNA filaments to tether biochemical activities to specific chromosomal sites. Different filaments with chimeric RecA proteins were tested for the ability to induce loss of heterozygosity at the golden locus in zebrafish after injection at the one-cell stage. A fusion protein between RecA containing a nuclear localization signal (NLS) and the DNA-binding domain of Gal4 (NLS-RecA-Gal4) displayed the most activity. Our results demonstrate that complementary ssDNA filaments as short as 60 nucleotides coated with NLS-RecA-Gal4 protein are able to cause loss of heterozygosity in ∼3% of the injected embryos. We demonstrate that lesions in ∼9% of the F0 zebrafish are transmitted to subsequent generations as large chromosomal deletions. Co-injection of linear DNA with the NLS-RecA-Gal4 DNA filaments promotes the insertion of the DNA into targeted genomic locations. Our data support a model whereby NLS-RecA-Gal4 DNA filaments bind to complementary target sites on chromatin and stall DNA replication forks, resulting in a DNA DSB.
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Affiliation(s)
- Hsin-Kai Liao
- Department of Genetics, Iowa State University, Ames, IA 50011, USA
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27
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Linear group II intron RNAs can retrohome in eukaryotes and may use nonhomologous end-joining for cDNA ligation. Proc Natl Acad Sci U S A 2009; 106:18189-94. [PMID: 19833873 DOI: 10.1073/pnas.0910277106] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mobile group II introns retrohome by an RNP-based mechanism in which the excised intron lariat RNA fully reverse splices into a DNA site via 2 sequential transesterification reactions and is reverse transcribed by the associated intron-encoded protein. However, linear group II intron RNAs, which can arise by either hydrolytic splicing or debranching of lariat RNA, cannot carry out both reverse-splicing steps and were thus expected to be immobile. Here, we used facile microinjection assays in 2 eukaryotic systems, Xenopus laevis oocyte nuclei and Drosophila melanogaster embryos, to show that group II intron RNPs containing linear intron RNA can retrohome by carrying out the first step of reverse splicing into a DNA site, thereby ligating the 3' end of the intron RNA to the 5' end of the downstream exon DNA. The attached linear intron RNA is then reverse transcribed, yielding an intron cDNA whose free end is linked to the upstream exon DNA. Some of these retrohoming events result in the precise insertion of full-length intron. Most, however, yield aberrant 5' junctions with 5' exon resections, 5' intron truncations, and/or extra nucleotide residues, hallmarks of nonhomologous end-joining. Our findings reveal a mobility mechanism for linear group II intron RNAs, show how group II introns can co-opt different DNA repair pathways for retrohoming, and suggest that linear group II intron RNAs might be used for site-specific DNA integration in gene targeting.
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28
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Deiters A, Yoder JA. Conditional transgene and gene targeting methodologies in zebrafish. Zebrafish 2008; 3:415-29. [PMID: 18377222 DOI: 10.1089/zeb.2006.3.415] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The zebrafish has become a powerful tool for dissecting vertebrate gene function during embryogenesis. Numerous molecular systems have been developed to examine gene function in zebrafish, including transgenics for creating lineage-tracer lines of zebrafish that express a fluorescent protein as a marker for specific populations of cells, and antisense strategies, primarily morpholinos, for knocking down gene function. The focus of this review is to summarize the pros and cons of the currently available systems for functional genomics in zebrafish, and to discuss the need for future methodologies.
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Affiliation(s)
- Alexander Deiters
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
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29
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Derijck A, van der Heijden G, Giele M, Philippens M, de Boer P. DNA double-strand break repair in parental chromatin of mouse zygotes, the first cell cycle as an origin of de novo mutation. Hum Mol Genet 2008; 17:1922-37. [PMID: 18353795 DOI: 10.1093/hmg/ddn090] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In the human, the contribution of the sexes to the genetic load is dissimilar. Especially for point mutations, expanded simple tandem repeats and structural chromosome mutations, the contribution of the male germline is dominant. Far less is known about the male germ cell stage(s) that are most vulnerable to mutation contraction. For the understanding of de novo mutation induction in the germline, mechanistic insight of DNA repair in the zygote is mandatory. At the onset of embryonic development, the parental chromatin sets occupy one pronucleus (PN) each and DNA repair can be regarded as a maternal trait, depending on proteins and mRNAs provided by the oocyte. Repair of DNA double-strand breaks (DSBs) is executed by non-homologous end joining (NHEJ) and homologous recombination (HR). Differentiated somatic cells often resolve DSBs by NHEJ, whereas embryonic stem cells preferably use HR. We show NHEJ and HR to be both functional during the zygotic cell cycle. NHEJ is already active during replacement of sperm protamines by nucleosomes. The kinetics of G1 repair is influenced by DNA-PK(cs) hypomorphic activity. Both HR and NHEJ are operative in S-phase, HR being more active in the male PN. DNA-PK(cs) deficiency upregulates the HR activity. Both after sperm remodeling and at first mitosis, spontaneous levels of gammaH2AX foci (marker for DSBs) are high. All immunoflurescent indices of DNA damage and DNA repair point at greater spontaneous damage and induced repair activity in paternal chromatin in the zygote.
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Affiliation(s)
- Alwin Derijck
- Department of Obstetrics and Gynaecology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
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30
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Fan L, Moon J, Crodian J, Collodi P. Homologous Recombination in Zebrafish ES Cells. Transgenic Res 2006; 15:21-30. [PMID: 16475007 DOI: 10.1007/s11248-005-3225-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Accepted: 09/17/2005] [Indexed: 11/25/2022]
Abstract
Targeted insertion of a plasmid by homologous recombination was demonstrated in zebrafish ES cell cultures. Two selection strategies were used to isolate ES cell colonies that contained targeted plasmid insertions in either the no tail or myostatin I gene. One selection strategy involved the manual isolation of targeted cell colonies that were identified by the loss of fluorescent protein gene expression. A second strategy used the diphtheria toxin A-chain gene in a positive-negative selection approach. Homologous recombination was confirmed by PCR, sequence and Southern blot analysis and colonies isolated using both selection methods were expanded and maintained for multiple passages. The results demonstrate that zebrafish ES cells have potential for use in a cell-mediated gene targeting approach.
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Affiliation(s)
- Lianchun Fan
- Department of Animal Sciences, Purdue University, 125 S. Russell Street, West Lafayette, IN 47907, USA
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31
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Weinert BT, Min B, Rio DC. P element excision and repair by non-homologous end joining occurs in both G1 and G2 of the cell cycle. DNA Repair (Amst) 2005; 4:171-81. [PMID: 15590325 DOI: 10.1016/j.dnarep.2004.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2004] [Revised: 09/09/2004] [Accepted: 09/10/2004] [Indexed: 10/26/2022]
Abstract
P element excision generates a DNA double-strand break at the transposon donor site. Genetic studies have demonstrated a strong bias toward repair of P element-induced DNA breaks by homologous recombination with the sister chromatid, suggesting that P element excision occurs after DNA replication, in G2 of the cell cycle. We developed methods to arrest Drosophila tissue culture cells and assay P element excision in either G1- or G2-arrested cells. Dacapo or tribbles transgene expression arrests cells in either G2 or G2, respectively. RNA-mediated gene interference (RNAi) directed against cyclin E or cyclin A arrests cells in G1 or G2, respectively. P element excision occurs efficiently in both G1- and G2-arrested cells, suggesting that cell cycle regulation of P element transposase does not occur in our somatic cell system. DNA double-strand break repair occurs by two predominant mechanisms: homologous recombination (HR) and non-homologous end joining (NHEJ). HR is thought to be restricted to the post-replicative, G2, phase of the cell cycle, while NHEJ may occur throughout the cell cycle. Our results indicate that NHEJ repair of an extrachromasomal plasmid substrate occurs at least as efficiently in G2-arrested cells as in asynchronous cells or in G1-arrested cells.
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Affiliation(s)
- Brian T Weinert
- Department of Molecular and Cell Biology, Center for Integrative Genomics, University of California, Berkeley, 16 Barker Hall, CA 94720-3204, USA
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32
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Romeijn RJ, Gorski MM, van Schie MA, Noordermeer JN, Mullenders LH, Ferro W, Pastink A. Lig4 and rad54 are required for repair of DNA double-strand breaks induced by P-element excision in Drosophila. Genetics 2004; 169:795-806. [PMID: 15545651 PMCID: PMC1449100 DOI: 10.1534/genetics.104.033464] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Site-specific double-strand breaks (DSBs) were generated in the white gene located on the X chromosome of Drosophila by excision of the w(hd) P-element. To investigate the role of nonhomologous end joining (NHEJ) and homologous recombination (HR) in the repair of these breaks, the w(hd) P-element was mobilized in flies carrying mutant alleles of either lig4 or rad54. The survival of both lig4- and rad54-deficient males was reduced to 25% in comparison to the wild type, indicating that both NHEJ and HR are involved in the repair P-induced gaps in males. Survival of lig4-deficient females was not affected at all, implying that HR using the homologous chromosome as a template can partially compensate for the impaired NHEJ pathway. In rad54 mutant females survival was reduced to 70% after w(hd) excision. PCR analysis indicated that the undamaged homologous chromosome may compensate for the potential loss of the broken chromosome in rad54 mutant females after excision. Molecular analysis of the repair junctions revealed microhomology (2-8 bp)-dependent DSB repair in most products. In the absence of Lig4, the 8-bp target site duplication is used more frequently for repair. Our data indicate the presence of efficient alternative end-joining mechanisms, which partly depend on the presence of microhomology but do not require Lig4.
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Affiliation(s)
- Ron J Romeijn
- Department of Toxicogenetics, Leiden University Medical Center (LUMC), 2333 AL, Leiden, The Netherlands
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33
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Hong Y, Chen S, Gui J, Schartl M. Retention of the developmental pluripotency in medaka embryonic stem cells after gene transfer and long-term drug selection for gene targeting in fish. Transgenic Res 2004; 13:41-50. [PMID: 15070074 DOI: 10.1023/b:trag.0000017172.71391.fa] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Embryonic stem (ES) cells provide a unique tool for introducing random or targeted genetic alterations, because it is possible that the desired, but extremely rare recombinant genotypes can be screened by drug selection. ES cell-mediated transgenesis has so far been limited to the mouse. In the fish medaka (Oryzias latipes) several ES cell lines have been made available. Here we report the optimized conditions for gene transfer and drug selection in the medaka ES cell line MES1 as a prelude for gene targeting in fish. MES1 cells gave rise to a moderate to high transfection efficiency by the calcium phosphate co-precipitation (5%), commercial reagents Fugene (11%), GeneJuice (21%) and electroporation (>30%). Transient gene transfer and CAT reporter assay revealed that several enhancers/promoters and their combinations including CMV, RSV and ST (the SV40 virus early gene enhancer linked to the thymidine kinase promoter) were suitable regulatory sequences to drive transgene expression in the MES1 cells. We show that neo, hyg or pac conferred resistance to G418, hygromycin or puromycin for positive selection, while the HSV-tk generated sensitivity to ganciclovir for negative selection. The positive-negative selection procedure that is widely used for gene targeting in mouse ES cells was found to be effective also in MES1 cells. Importantly, we demonstrate that MES1 cells after gene transfer and long-term drug selection retained the developmental pluripotency, as they were able to undergo induced differentiation in vitro and to contribute to various tissues and organs during chimeric embryogenesis.
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Affiliation(s)
- Yunhan Hong
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore.
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34
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Doré AS, Drake ACB, Brewerton SC, Blundell TL. Identification of DNA-PK in the arthropods. Evidence for the ancient ancestry of vertebrate non-homologous end-joining. DNA Repair (Amst) 2004; 3:33-41. [PMID: 14697757 DOI: 10.1016/j.dnarep.2003.09.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cellular life depends upon the preservation and transmission of genetic material. Double stranded DNA breaks (DSBs) cause catastrophic gene loss in cell division and must be promptly and accurately repaired. In eukaryotes DSBs may be repaired by either non-homologous end-joining (NHEJ), single strand annealing or homologous recombination (HR). Vertebrate NHEJ has been shown to depend upon the DNA-dependent protein kinase (DNA-PK) consisting of the phosphatidylinositol 3 (PI 3)-kinase like (PIKK) catalytic sub-unit (DNA-PKcs) and the DNA targeting factor Ku. Our analysis of recently completed genomes found several novel PIKKs in Anopheles gambiae and Drosophila melanogaster including a novel mosquito DNA-PKcs orthologue, the first non-vertebrate DNA-PKcs described to date. We also detected a DNA-PKcs fragment in the high quality EST set of Apis mellifera ligustica (honey bee) suggesting that DNA-PK is a far older and more important eukaryotic complex than previously thought.
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Affiliation(s)
- Andrew S Doré
- Department of Biochemistry, University of Cambridge, Old Addenbrookes site, 80 Tennis Court Road, CB2 1GA, Cambridge, UK
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35
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Egli D, Hafen E, Schaffner W. An efficient method to generate chromosomal rearrangements by targeted DNA double-strand breaks in Drosophila melanogaster. Genome Res 2004; 14:1382-93. [PMID: 15197166 PMCID: PMC442155 DOI: 10.1101/gr.2279804] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Homologous recombination (HR) is an indispensable tool to modify the genome of yeast and mammals. More recently HR is also being used for gene targeting in Drosophila. Here we show that HR can be used efficiently to engineer chromosomal rearrangements such as pericentric and paracentric inversions and translocations in Drosophila. Two chromosomal double-strand breaks (DSBs), introduced by the rare-cutting I-SceI endonuclease on two different mobile elements sharing homologous sequences, are sufficient to promote rearrangements at a frequency of 1% to 4%. Such rearrangements, once generated by HR, can be reverted by Cre recombinase. However, Cre-mediated recombination efficiency drops with increasing distance between recombination sites, unlike HR. We therefore speculate that physical constraints on chromosomal movement are modulated during DSB repair, to facilitate the homology search throughout the genome.
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Affiliation(s)
- Dieter Egli
- Institut für Molekularbiologie, CH-8057 Zürich, Switzerland
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36
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Kopeika J, Kopeika E, Zhang T, Rawson DM, Holt WV. Effect of DNA repair inhibitor (3-aminobenzamide) on genetic stability of loach (Misgurnus fossilis) embryos derived from cryopreserved sperm. Theriogenology 2004; 61:1661-73. [PMID: 15019462 DOI: 10.1016/j.theriogenology.2003.09.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2003] [Revised: 09/03/2003] [Accepted: 09/06/2003] [Indexed: 11/20/2022]
Abstract
Semen cryopreservation is widely used in clinical medicine, agriculture, aquaculture and biomedical research, but it is an inefficient technique that induces extensive cytoplasmic damage and loss of fertilising ability. Whether any genetic damage (i.e. DNA strand breakage or mutation) is also induced is still unclear. However, previous data has indicated that this is likely. The present study was designed to explore this possibility further by using inhibitors of the DNA repair system to block DNA repair in embryos derived from cryopreserved spermatozoa. If cryopreservation causes strand breaks in sperm DNA it might be expected that inhibition of a repair enzyme such as poly(ADP-ribose) polymerase (PARP) would enhance any such negative effect of cryopreservation. To check this hypothesis 3-aminobenzamide (3-AB) was used as an inhibitor of PARP. Weather loach (Misgurnus fossilis) eggs were fertilised using cryopreserved as well as fresh spermatozoa. Embryos derived from cryopreserved spermatozoa were exposed to 10 mM 3-AB for 2 h after fertilisation. The experiments were carried out using 43,544 embryos from 5 females and 10 males. Embryo survival was evaluated at different stages until the hatching stage. Sperm cryopreservation significantly decreased embryo survival (53.6+/-2.79% compared to 76.97+/-2.79% of control; P<0.01). The addition of 3-AB to the medium with embryos derived from cryopreserved sperm further decreased embryo survival from 53.6+/-2.79% to 46.1+/-2.79% (P<0.01) whereas there was no adverse effect of 3-AB exposed embryos derived from fresh sperm (76.97+/-2.79% of control compared to 74.8+/-2.79% of control+3-AB). The effect of 3-AB provides indirect evidence that cryopreservation might induce instability in sperm DNA, and that such damage can be repaired by the oocyte repair system after fertilisation.
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Affiliation(s)
- Julia Kopeika
- Luton Institute of Research in the Applied Natural Sciences, University of Luton, The Spires, 2 Adelaide Street, Luton LU1 5DU, UK
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37
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Stuckenholz C, Ulanch PE, Bahary N. From guts to brains: using zebrafish genetics to understand the innards of organogenesis. Curr Top Dev Biol 2004; 65:47-82. [PMID: 15642379 DOI: 10.1016/s0070-2153(04)65002-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Carsten Stuckenholz
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pennsylvania 15261, USA
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38
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Affiliation(s)
- Andrew Dodd
- Molecular Genetics and Development Group, School of Biological Sciences, University of Auckland, Auckland 1001, New Zealand
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39
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Schartl M, Nanda I, Kondo M, Schmid M, Asakawa S, Sasaki T, Shimizu N, Henrich T, Wittbrodt J, Furutani-Seiki M, Kondoh H, Himmelbauer H, Hong Y, Koga A, Nonaka M, Mitani H, Shima A. Current status of medaka genetics and genomics. The Medaka Genome Initiative (MGI). Methods Cell Biol 2004; 77:173-99. [PMID: 15602912 DOI: 10.1016/s0091-679x(04)77010-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Manfred Schartl
- Biocenter, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg, Germany
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40
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Kopeika J, Kopeika E, Zhang T, Rawson DM, Holt WV. Detrimental effects of cryopreservation of loach (Misgurnus fossilis) sperm on subsequent embryo development are reversed by incubating fertilised eggs in caffeine. Cryobiology 2003; 46:43-52. [PMID: 12623027 DOI: 10.1016/s0011-2240(02)00162-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cryopreservation can cause changes to the genetic material of cells, but the mechanism and significance of these changes are still unknown. It has been suggested that some damage to the sperm genome could be repaired by the DNA repair system of the oocyte after fertilisation. Caffeine has been reported to be an inhibitor of such repair processes. In this study the effect of caffeine on the repair system of Loach (Misgurnus fossilis) oocytes was investigated. Loach eggs were fertilised using cryopreserved sperm. Embryos derived from cryopreserved sperm were exposed to 2.6mM caffeine for 1h after fertilisation. The experiments were carried out using 32313 embryos from four females and eight males. Embryo survival was evaluated for 46 h until the hatching stage. Reduction in embryo survival after 20th stage is generally believed to result from the failure in the genome function of embryos. Cryopreservation of sperm significantly decreased embryo survival (53.4+/-2.8% compared to 68.4+/-2.8% of control) after the 20th stage. However, the addition of caffeine to the embryos derived from cryopreserved sperm, in contrast to our expectation, significantly increased survival of loach embryos (70.9+/-2.8% compared to 53.4+/-2.8% of embryos derived from cryopreserved sperm in the absence of caffeine). The effect of individual donors of sperm and eggs on overall embryo survival was also studied. Whilst no significant differences were observed between males, the effect of individual females on embryo survival was significant. The analysis of embryo survival at different developmental stages showed that embryo survival both before and after 20th stage decreased with embryo development. When fresh sperm were used the decline of embryo survival with development was more pronounced compared with those embryos derived from cryopreserved sperm. Possible explanations of these effects are presented.
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Affiliation(s)
- J Kopeika
- Luton Institute of Research in the Applied Natural Sciences, University of Luton, The Spires, 2 Adelaide Street, Luton, LU1 5DU, UK
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41
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Egli D, Selvaraj A, Yepiskoposyan H, Zhang B, Hafen E, Georgiev O, Schaffner W. Knockout of 'metal-responsive transcription factor' MTF-1 in Drosophila by homologous recombination reveals its central role in heavy metal homeostasis. EMBO J 2003; 22:100-8. [PMID: 12505988 PMCID: PMC140060 DOI: 10.1093/emboj/cdg012] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2002] [Revised: 11/06/2002] [Accepted: 11/07/2002] [Indexed: 11/13/2022] Open
Abstract
'Metal-responsive transcription factor-1' (MTF-1), a zinc finger protein, is conserved from mammals to insects. In the mouse, it activates metallothionein genes and other target genes in response to several cell stress conditions, notably heavy metal load. The knockout of MTF-1 in the mouse has an embryonic lethal phenotype accompanied by liver degeneration. Here we describe the targeted disruption of the MTF-1 gene in Drosophila by homologous recombination. Unlike the situation in the mouse, knockout of MTF-1 in Drosophila is not lethal. Flies survive well under laboratory conditions but are sensitive to elevated concentrations of copper, cadmium and zinc. Basal and metal-induced expression of Drosophila metallothionein genes MtnA (Mtn) and MtnB (Mto), and of two new metallothionein genes described here, MtnC and MtnD, is abolished in MTF-1 mutants. Unexpectedly, MTF-1 mutant larvae are sensitive not only to copper load but also to copper depletion. In MTF-1 mutants, copper depletion prevents metamorphosis and dramatically extends larval development/lifespan from normally 4-5 days to as many as 32 days, possibly reflecting the effects of impaired oxygen metabolism. These findings expand the roles of MTF-1 in the control of heavy metal homeostasis.
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Affiliation(s)
| | | | | | | | - Ernst Hafen
- Institut für Molekularbiologie and
Zoologisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland Corresponding author e-mail:
| | | | - Walter Schaffner
- Institut für Molekularbiologie and
Zoologisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland Corresponding author e-mail:
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Preston CR, Engels W, Flores C. Efficient repair of DNA breaks in Drosophila: evidence for single-strand annealing and competition with other repair pathways. Genetics 2002; 161:711-20. [PMID: 12072467 PMCID: PMC1462149 DOI: 10.1093/genetics/161.2.711] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We show evidence that DNA double-strand breaks induced in the Drosophila germ line can be repaired very efficiently by the single-strand annealing (SSA) mechanism. A double-strand break was made between two copies of a 1290-bp direct repeat by mobilizing a P transposon. In >80% of the progeny that acquired this chromosome, repair resulted in loss of the P element and loss of one copy of the repeat, as observed in SSA. The frequency of this repair was much greater than seen for gene conversion using an allelic template, which is only approximately 7%. A similar structure, but with a smaller duplication of only 158 bp, also yielded SSA-like repair events, but at a reduced frequency, and gave rise to some products by repair pathways other than SSA. The 1290-bp repeats carried two sequence polymorphisms that were examined in the products. The allele nearest to a nick in the putative heteroduplex intermediate was lost most often. This bias is predicted by the SSA model, although other models could account for it. We conclude that SSA is the preferred repair pathway in Drosophila for DNA breaks between sequence repeats, and it competes with gene conversion by the synthesis-dependent strand annealing (SDSA) pathway.
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Affiliation(s)
- Christine R Preston
- Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
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45
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Eggleston P, Zhao Y. A sensitive and rapid assay for homologous recombination in mosquito cells: impact of vector topology and implications for gene targeting. BMC Genet 2001; 2:21. [PMID: 11801182 PMCID: PMC64643 DOI: 10.1186/1471-2156-2-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2001] [Accepted: 12/17/2001] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recent progress in insect transgenesis has been dramatic but existing transposon-based approaches are constrained by position effects and potential instability. Gene targeting would bring a number of benefits, however progress requires a better understanding of the mechanisms involved. Much can be learned in vitro since extrachromosomal recombination occurs at high frequency, facilitating the study of multiple events and the impact of structural changes among the recombining molecules. We have investigated homologous recombination in mosquito cells through restoration of luciferase activity from deleted substrates. The implications of this work for the construction of insect gene targeting vectors are discussed. RESULTS We show that linear targeting vectors are significantly more efficient than circular ones and that recombination is stimulated by introducing double-strand breaks into, or near, the region of homology. Single-strand annealing represents a very efficient pathway but may not be feasible for targeting unbroken chromosomes. Using circular plasmids to mimic chromosomal targets, one-sided invasion appears to be the predominant pathway for homologous recombination. Non-homologous end joining reactions also occur and may be utilised in gene targeting if double-strand breaks are first introduced into the target site. CONCLUSIONS We describe a rapid, sensitive assay for extrachromosomal homologous recombination in mosquito cells. Variations in substrate topology suggest that single-strand annealing and one-sided invasion represent the predominant pathways, although non-homologous end joining reactions also occur. One-sided invasion of circular chromosomal mimics by linear vectors might therefore be used in vitro to investigate the design and efficiency of gene targeting strategies.
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Affiliation(s)
- Paul Eggleston
- School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK
| | - Yuguang Zhao
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, OX3 9DS, UK
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46
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Hsiao CD, Hsieh FJ, Tsai HJ. Enhanced expression and stable transmission of transgenes flanked by inverted terminal repeats from adeno-associated virus in zebrafish. Dev Dyn 2001; 220:323-36. [PMID: 11307166 DOI: 10.1002/dvdy.1113] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mosaic expression of transgenes in the F0 generation severely hinders the study of transient expression in transgenic fish. To avoid mosaicism, enhanced green fluorescent protein (EGFP) gene cassettes were constructed and introduced into one-celled zebrafish embryos. These EGFP gene cassettes were flanked by inverted terminal repeats (ITRs) from adeno-associated virus (AAV) and driven by zebrafish alpha-actin (palpha-actin-EGFP-ITR) or medaka beta-actin promoters (pbeta-actin-EGFP-ITR). EGFP was expressed specifically and uniformly in the skeletal muscle of 56% +/- 8% of the palpha-actin-EGFP-ITR-injected survivors and in the entire body of 1.3% +/- 0.8% of the pbeta-actin-EGFP-ITR-injected survivors. Uniform transient expression never occurred in zebrafish embryos injected with EGFP genes that were not flanked by AAV-ITRs. In the F0 generation, uniformly distributed EGFP could mimic the stable expression in transgenic lines early in development. We established five transgenic lines derived from palpha-actin-EGFP-ITR-injected embryos crossed with wild-type fish and 11 transgenic lines derived from pbeta-actin-EGFP-ITR-injected embryos crossed with wild-type fish. None of these transgenic lines failed to express the transgene, a result confirmed by polymerase chain reaction analysis. Stable mendelian transmission of the transgenes was achieved in both alpha-actin and beta-actin transgenic lines without changing the patterns of expression and integration. Progeny inheritance test and Southern blot analysis results strongly suggest that transgenes flanked by AAV-ITRs were integrated randomly into the genome at a single locus with a concatamerized multiplier. Thus, incorporating AAV-ITRs into transgenes results in uniform gene expression in the F0 generation and stable transmission of transgenes in zebrafish.
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Affiliation(s)
- C D Hsiao
- Institute of Fisheries Science, National Taiwan University, Taipei, Taiwan
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47
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Ducau J, Bregliano JC, de La Roche Saint-André C. Gamma-irradiation stimulates homology-directed DNA double-strand break repair in Drosophila embryo. Mutat Res 2000; 460:69-80. [PMID: 10856836 DOI: 10.1016/s0921-8777(00)00017-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To test the DNA double-strand break (DSB) repair activities present in Drosophila early embryos, we have analyzed the circularization of a microinjected linear plasmid. In order to study repair by homologous recombination, the linear plasmid was injected with an homologous fragment encompassing the break. After extraction from embryos, repair products were analyzed directly by PCR and after their cloning into bacteria. We demonstrate, in addition to the repair by homologous recombination, the presence of an efficient end-joining activity in embryos. Plasmid circularization by end-joining was accompanied by short deletions frequently associated with non-random insertions. Most importantly, pre-irradiation of embryos specifically enhanced the accurate repair by homologous recombination. Such a stimulation is described for the first time in the context of a whole higher organism.
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MESH Headings
- Animals
- Base Sequence
- DNA/administration & dosage
- DNA/genetics
- DNA/metabolism
- DNA/radiation effects
- DNA Mutational Analysis
- DNA Repair/genetics
- DNA Repair/radiation effects
- DNA, Circular/genetics
- DNA, Circular/metabolism
- DNA, Circular/radiation effects
- Drosophila/embryology
- Drosophila/enzymology
- Drosophila/genetics
- Drosophila/radiation effects
- Embryo, Nonmammalian/enzymology
- Embryo, Nonmammalian/metabolism
- Embryo, Nonmammalian/radiation effects
- Gamma Rays
- Microinjections
- Models, Genetic
- Molecular Sequence Data
- Mutation/genetics
- Mutation/radiation effects
- Plasmids/genetics
- Plasmids/metabolism
- Plasmids/radiation effects
- Polymerase Chain Reaction
- Recombination, Genetic/genetics
- Recombination, Genetic/radiation effects
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- J Ducau
- Laboratoire de Génétique et Physiologie de Développement, Institut de Biologie du Développement de Marseille, Université de la Méditerranée, 13288 Cedex 9, Marseilles, France
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