1
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Bai J, Kondo R, Mayasari NI, Shigeoka T, Isotani A, Ikawa M, Sashida G, Kawaichi M, Ishida Y. Diphtheria toxin-mediated transposon-driven poly (A)-trapping efficiently disrupts transcriptionally silent genes in embryonic stem cells. Genesis 2020; 58:e23386. [PMID: 32645254 DOI: 10.1002/dvg.23386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 11/10/2022]
Abstract
Random gene trapping is the application of insertional mutagenesis techniques that are conventionally used to inactivate protein-coding genes in mouse embryonic stem (ES) cells. Transcriptionally silent genes are not effectively targeted by conventional random gene trapping techniques, thus we herein developed an unbiased poly (A) trap (UPATrap) method using a Tol2 transposon, which preferentially integrated into active genes rather than silent genes in ES cells. To achieve efficient trapping at transcriptionally silent genes using random insertional mutagenesis in ES cells, we generated a new diphtheria toxin (DT)-mediated trapping vector, DTrap that removed cells, through the expression of DT that was induced by the promoter activity of the trapped genes, and selected trapped clones using the neomycin-resistance gene of the vector. We found that a double-DT, the dDT vector, dominantly induced the disruption of silent genes, but not active genes, and showed more stable integration in ES cells than the UPATrap vector. The dDT vector disrupted differentiated cell lineage genes, which were silent in ES cells, and labeled trapped clone cells by the expression of EGFP upon differentiation. Thus, the dDT vector provides a systematic approach to disrupt silent genes and examine the cellular functions of trapped genes in the differentiation of target cells and development.
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Affiliation(s)
- Jie Bai
- Laboratory of Functional Genomics and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan.,Laboratory of Transcriptional Regulation in Leukemogenesis, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Ryohei Kondo
- Laboratory of Functional Genomics and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan.,Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - N Ika Mayasari
- Laboratory of Functional Genomics and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan.,Faculty of Veterinary Medicine, Bogor Agricultural University (IPB), Jalan Agatis Kampus IPB Darmaga, Bogor, West Java, Indonesia
| | - Toshiaki Shigeoka
- Laboratory of Functional Genomics and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan.,Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Ayako Isotani
- Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Organ Developmental Engineering, Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Goro Sashida
- Laboratory of Transcriptional Regulation in Leukemogenesis, International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Masashi Kawaichi
- Division of Educational Development, Nara Institute of Science and Technology, Nara, Japan
| | - Yasumasa Ishida
- Laboratory of Functional Genomics and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
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2
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Yamanishi A, Matsuba A, Kondo R, Akamatsu R, Tanaka S, Tokunaga M, Horie K, Kokubu C, Ishida Y, Takeda J. Collection of homozygous mutant mouse embryonic stem cells arising from autodiploidization during haploid gene trap mutagenesis. Nucleic Acids Res 2019; 46:e63. [PMID: 29554276 PMCID: PMC6007410 DOI: 10.1093/nar/gky183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/09/2018] [Indexed: 12/22/2022] Open
Abstract
Haploid mouse embryonic stem cells (ESCs), in which a single hit mutation is sufficient to produce loss-of-function phenotypes, have provided a powerful tool for forward genetic screening. This strategy, however, can be hampered by undesired autodiploidization of haploid ESCs. To overcome this obstacle, we designed a new methodology that facilitates enrichment of homozygous mutant ESC clones arising from autodiploidization during haploid gene trap mutagenesis. Haploid mouse ESCs were purified by fluorescence-activated cell sorting to maintain their haploid property and then transfected with the Tol2 transposon-based biallelically polyA-trapping (BPATrap) vector that carries an invertible G418 plus puromycin double selection cassette. G418 plus puromycin double selection enriched biallelic mutant clones that had undergone autodiploidization following a single vector insertion into the haploid genome. Using this method, we successfully generated 222 homozygous mutant ESCs from 2208 clones by excluding heterozygous ESCs and ESCs with multiple vector insertions. This relatively low efficiency of generating homozygous mutant ESCs was partially overcome by cell sorting of haploid ESCs after Tol2 BPATrap transfection. These results demonstrate the feasibility of our approach to provide an efficient platform for mutagenesis of ESCs and functional analysis of the mammalian genome.
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Affiliation(s)
- Ayako Yamanishi
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Atsushi Matsuba
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Ryohei Kondo
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Rie Akamatsu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Sachiyo Tanaka
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahiro Tokunaga
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kyoji Horie
- Department of Physiology II, Nara Medical University, Kashihara, Nara 634-8521, Japan
| | - Chikara Kokubu
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasumasa Ishida
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Junji Takeda
- Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
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3
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Schumann GG, Fuchs NV, Tristán-Ramos P, Sebe A, Ivics Z, Heras SR. The impact of transposable element activity on therapeutically relevant human stem cells. Mob DNA 2019; 10:9. [PMID: 30899334 PMCID: PMC6408843 DOI: 10.1186/s13100-019-0151-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/27/2019] [Indexed: 12/11/2022] Open
Abstract
Human stem cells harbor significant potential for basic and clinical translational research as well as regenerative medicine. Currently ~ 3000 adult and ~ 30 pluripotent stem cell-based, interventional clinical trials are ongoing worldwide, and numbers are increasing continuously. Although stem cells are promising cell sources to treat a wide range of human diseases, there are also concerns regarding potential risks associated with their clinical use, including genomic instability and tumorigenesis concerns. Thus, a deeper understanding of the factors and molecular mechanisms contributing to stem cell genome stability are a prerequisite to harnessing their therapeutic potential for degenerative diseases. Chemical and physical factors are known to influence the stability of stem cell genomes, together with random mutations and Copy Number Variants (CNVs) that accumulated in cultured human stem cells. Here we review the activity of endogenous transposable elements (TEs) in human multipotent and pluripotent stem cells, and the consequences of their mobility for genomic integrity and host gene expression. We describe transcriptional and post-transcriptional mechanisms antagonizing the spread of TEs in the human genome, and highlight those that are more prevalent in multipotent and pluripotent stem cells. Notably, TEs do not only represent a source of mutations/CNVs in genomes, but are also often harnessed as tools to engineer the stem cell genome; thus, we also describe and discuss the most widely applied transposon-based tools and highlight the most relevant areas of their biomedical applications in stem cells. Taken together, this review will contribute to the assessment of the risk that endogenous TE activity and the application of genetically engineered TEs constitute for the biosafety of stem cells to be used for substitutive and regenerative cell therapies.
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Affiliation(s)
- Gerald G Schumann
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Nina V Fuchs
- 2Host-Pathogen Interactions, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51-59, 63225 Langen, Germany
| | - Pablo Tristán-Ramos
- 3GENYO. Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada-Avenida de la Ilustración, 114, 18016 Granada, Spain.,4Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
| | - Attila Sebe
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Zoltán Ivics
- 1Division of Medical Biotechnology, Paul-Ehrlich-Institut, Paul-Ehrlich-Str.51-59, 63225 Langen, Germany
| | - Sara R Heras
- 3GENYO. Centre for Genomics and Oncological Research, Pfizer/University of Granada/Andalusian Regional Government, PTS Granada-Avenida de la Ilustración, 114, 18016 Granada, Spain.,4Department of Biochemistry and Molecular Biology II, Faculty of Pharmacy, University of Granada, Campus Universitario de Cartuja, 18071 Granada, Spain
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4
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Zhao Y, Song G, Ren J, Li Q, Zhong S, Cui Z. Sleeping beauty transposon-mediated poly(A)-trapping and insertion mutagenesis in mouse embryonic stem cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:687-697. [PMID: 30280432 DOI: 10.1002/em.22234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/03/2018] [Accepted: 07/12/2018] [Indexed: 06/08/2023]
Abstract
Saturation mutagenesis of all endogenous genes within the mouse genome remains a challenging task, although a plenty of gene-editing approaches are available for this purpose. Here, a poly(A)-trap vector was generated for insertion mutagenesis in mouse embryonic stem (mES) cells. This vector contains an expression cassette of neomycin (Neo)-resistant gene lacking a poly(A) signal and flanked by two inverted terminal repeats of the Sleeping Beauty (SB) transposon. The whole poly(A)-trap cassette can transpose into target TA dinucleotides, properly splice with endogenous genes and effectively interrupt the transcription of trapped genes in mES cells after transient induction of SB expression by doxycycline (DOX)-treatment at 1 μg/ml, leading to the formation of multiple geneticin (G418)-resistant cell clones. In the first round of mutation screening, we identified six transposition events from 23 cell clones, including four inserted into an endogenous gene and two landed between endogenous genes. The abilities of self-renewal, totipotency, genetic stability and differentiation of syngap1+/- cells were not affected by DOX-treatment and G418-selection. These findings suggest that this SB transposon-mediated poly(A)-trap vector can be used as an alternative tool for a large-scale screening of mES cells with a gene mutation and for further generation of mutant mouse strains. Environ. Mol. Mutagen. 59:687-697, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Yi Zhao
- Department of Genetics, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Guili Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jing Ren
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Qing Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Shan Zhong
- Department of Genetics, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Allergy and Immunology, Wuhan, Hubei, China
| | - Zongbin Cui
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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5
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Krastev DB, Pettitt SJ, Campbell J, Song F, Tanos BE, Stoynov SS, Ashworth A, Lord CJ. Coupling bimolecular PARylation biosensors with genetic screens to identify PARylation targets. Nat Commun 2018; 9:2016. [PMID: 29789535 PMCID: PMC5964205 DOI: 10.1038/s41467-018-04466-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/01/2018] [Indexed: 12/26/2022] Open
Abstract
Poly (ADP-ribose)ylation is a dynamic protein modification that regulates multiple cellular processes. Here, we describe a system for identifying and characterizing PARylation events that exploits the ability of a PBZ (PAR-binding zinc finger) protein domain to bind PAR with high-affinity. By linking PBZ domains to bimolecular fluorescent complementation biosensors, we developed fluorescent PAR biosensors that allow the detection of temporal and spatial PARylation events in live cells. Exploiting transposon-mediated recombination, we integrate the PAR biosensor en masse into thousands of protein coding genes in living cells. Using these PAR-biosensor "tagged" cells in a genetic screen we carry out a large-scale identification of PARylation targets. This identifies CTIF (CBP80/CBP20-dependent translation initiation factor) as a novel PARylation target of the tankyrase enzymes in the centrosomal region of cells, which plays a role in the distribution of the centrosomal satellites.
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Affiliation(s)
- Dragomir B Krastev
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK
| | - Stephen J Pettitt
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK
| | - James Campbell
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK
| | - Feifei Song
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK
| | - Barbara E Tanos
- The Cancer Therapeutics Division, The Institute of Cancer Research, London, SW3 6JB, UK
| | - Stoyno S Stoynov
- The Institute of Molecular Biology, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
| | - Alan Ashworth
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK.
- UCSF Helen Diller Family Comprehensive Cancer Center, 1450 3rd Street, San Francisco, CA, 94158, USA.
| | - Christopher J Lord
- The CRUK Gene Function Laboratory and Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK.
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6
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A reversible haploid mouse embryonic stem cell biobank resource for functional genomics. Nature 2017; 550:114-118. [PMID: 28953874 DOI: 10.1038/nature24027] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 08/18/2017] [Indexed: 12/21/2022]
Abstract
The ability to directly uncover the contributions of genes to a given phenotype is fundamental for biology research. However, ostensibly homogeneous cell populations exhibit large clonal variance that can confound analyses and undermine reproducibility. Here we used genome-saturated mutagenesis to create a biobank of over 100,000 individual haploid mouse embryonic stem (mES) cell lines targeting 16,970 genes with genetically barcoded, conditional and reversible mutations. This Haplobank is, to our knowledge, the largest resource of hemi/homozygous mutant mES cells to date and is available to all researchers. Reversible mutagenesis overcomes clonal variance by permitting functional annotation of the genome directly in sister cells. We use the Haplobank in reverse genetic screens to investigate the temporal resolution of essential genes in mES cells, and to identify novel genes that control sprouting angiogenesis and lineage specification of blood vessels. Furthermore, a genome-wide forward screen with Haplobank identified PLA2G16 as a host factor that is required for cytotoxicity by rhinoviruses, which cause the common cold. Therefore, clones from the Haplobank combined with the use of reversible technologies enable high-throughput, reproducible, functional annotation of the genome.
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7
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Okamoto-Uchida Y, Yu R, Miyamura N, Arima N, Ishigami-Yuasa M, Kagechika H, Yoshida S, Hosoya T, Nawa M, Kasama T, Asaoka Y, Alois RW, Elling U, Penninger JM, Nishina S, Azuma N, Nishina H. The mevalonate pathway regulates primitive streak formation via protein farnesylation. Sci Rep 2016; 6:37697. [PMID: 27883036 PMCID: PMC5121603 DOI: 10.1038/srep37697] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 11/02/2016] [Indexed: 01/25/2023] Open
Abstract
The primitive streak in peri-implantation embryos forms the mesoderm and endoderm and controls cell differentiation. The metabolic cues regulating primitive streak formation remain largely unknown. Here we utilised a mouse embryonic stem (ES) cell differentiation system and a library of well-characterised drugs to identify these metabolic factors. We found that statins, which inhibit the mevalonate metabolic pathway, suppressed primitive streak formation in vitro and in vivo. Using metabolomics and pharmacologic approaches we identified the downstream signalling pathway of mevalonate and revealed that primitive streak formation requires protein farnesylation but not cholesterol synthesis. A tagging-via-substrate approach revealed that nuclear lamin B1 and small G proteins were farnesylated in embryoid bodies and important for primitive streak gene expression. In conclusion, protein farnesylation driven by the mevalonate pathway is a metabolic cue essential for primitive streak formation.
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Affiliation(s)
- Yoshimi Okamoto-Uchida
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan.,Division of Medicinal Safety Science, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, Japan
| | - Ruoxing Yu
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan
| | - Norio Miyamura
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan
| | - Norie Arima
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan
| | - Mari Ishigami-Yuasa
- Chemical Biology Screening Center, Institute of Biomaterials and Bioengineering, TMDU, Tokyo, Japan
| | - Hiroyuki Kagechika
- Chemical Biology Screening Center, Institute of Biomaterials and Bioengineering, TMDU, Tokyo, Japan.,Department of Organic and Medicinal Chemistry, Institute of Biomaterials and Bioengineering, TMDU, Tokyo, Japan
| | - Suguru Yoshida
- Department of Chemical Bioscience, Institute of Biomaterials and Bioengineering, TMDU, Tokyo, Japan
| | - Takamitsu Hosoya
- Department of Chemical Bioscience, Institute of Biomaterials and Bioengineering, TMDU, Tokyo, Japan
| | - Makiko Nawa
- Laboratory of Cytometry and Proteome Research, TMDU, Tokyo, Japan
| | - Takeshi Kasama
- Instrumental Analysis Research Division, Research Center for Medical and Dental Sciences, TMDU, Tokyo, Japan
| | - Yoichi Asaoka
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan
| | - Reiner Wimmer Alois
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Ulrich Elling
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Josef M Penninger
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Sachiko Nishina
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
| | - Noriyuki Azuma
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
| | - Hiroshi Nishina
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan
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8
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Li L, Liu P, Sun L, Bin Zhou, Fei J. PiggyBac transposon-based polyadenylation-signal trap for genome-wide mutagenesis in mice. Sci Rep 2016; 6:27788. [PMID: 27292714 PMCID: PMC4904408 DOI: 10.1038/srep27788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 05/23/2016] [Indexed: 12/12/2022] Open
Abstract
We designed a new type of polyadenylation-signal (PAS) trap vector system in living mice, the piggyBac (PB) (PAS-trapping (EGFP)) gene trapping vector, which takes advantage of the efficient transposition ability of PB and efficient gene trap and insertional mutagenesis of PAS-trapping. The reporter gene of PB(PAS-trapping (EGFP)) is an EGFP gene with its own promoter, but lacking a poly(A) signal. Transgenic mouse lines carrying PB(PAS-trapping (EGFP)) and protamine 1 (Prm1) promoter-driven PB transposase transgenes (Prm1-PBase) were generated by microinjection. Male mice doubly positive for PB(PAS-trapping (EGFP)) and Prm1-PBase were crossed with WT females, generating offspring with various insertion mutations. We found that 44.8% (26/58) of pups were transposon-positive progenies. New transposon integrations comprised 26.9% (7/26) of the transposon-positive progenies. We found that 100% (5/5) of the EGFP fluorescence-positive mice had new trap insertions mediated by a PB transposon in transcriptional units. The direction of the EGFP gene in the vector was consistent with the direction of the endogenous gene reading frame. Furthermore, mice that were EGFP-PCR positive, but EGFP fluorescent negative, did not show successful gene trapping. Thus, the novel PB(PAS-trapping (EGFP)) system is an efficient genome-wide gene-trap mutagenesis in mice.
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Affiliation(s)
- Limei Li
- Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Department of vascular surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Peng Liu
- Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Department of Cardiology, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Liangliang Sun
- Department of Endocrinology, Changzheng Hospital, Second Military Medical University, Shanghai, 200003, PR China
| | - Bin Zhou
- Department of vascular surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Jian Fei
- Research Center for Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Metastasis research institute, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- School of Life Science and Technology, Tongji University, Shanghai, China
- Shanghai Research Center for Model Organisms, Shanghai, 201203, China
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9
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Abstract
hAT transposons are ancient in their origin and they are widespread across eukaryote kingdoms. They can be present in large numbers in many genomes. However, only a few active forms of these elements have so far been discovered indicating that, like all transposable elements, there is selective pressure to inactivate them. Nonetheless, there have been sufficient numbers of active hAT elements and their transposases characterized that permit an analysis of their structure and function. This review analyzes these and provides a comparison with the several domesticated hAT genes discovered in eukaryote genomes. Active hAT transposons have also been developed as genetic tools and understanding how these may be optimally utilized in new hosts will depend, in part, on understanding the basis of their function in genomes.
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10
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Genome wide functional genetics in haploid cells. FEBS Lett 2014; 588:2415-21. [PMID: 24950427 DOI: 10.1016/j.febslet.2014.06.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 01/02/2023]
Abstract
Some organisms such as yeast or males of social insects are haploid, i.e. they carry a single set of chromosomes, while haploidy in mammals is exclusively restricted to mature germ cells. A single copy of the genome provides the basis for genetic analyses where any recessive mutation of essential genes will show a clear phenotype due to the absence of a second gene copy. Most prominently, haploidy in yeast has been utilized for recessive genetic screens that have markedly contributed to our understanding of development, basic physiology, and disease. Somatic mammalian cells carry two copies of chromosomes (diploidy) that obscure genetic analysis. Near haploid human leukemic cells however have been developed as a high throughput screening tool. Although deemed impossible, we and others have generated mammalian haploid embryonic stem cells from parthenogenetic mouse embryos. Haploid stem cells open the possibility of combining the power of a haploid genome with pluripotency of embryonic stem cells to uncover fundamental biological processes in defined cell types at a genomic scale. Haploid genetics has thus become a powerful alternative to RNAi or CRISPR based screens.
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