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Penkov D, Zubkova E, Parfyonova Y. Tn5 DNA Transposase in Multi-Omics Research. Methods Protoc 2023; 6:mps6020024. [PMID: 36961044 PMCID: PMC10037646 DOI: 10.3390/mps6020024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/06/2023] Open
Abstract
Tn5 transposase use in biotechnology has substantially advanced the sequencing applications of genome-wide analysis of cells. This is mainly due to the ability of Tn5 transposase to efficiently transpose DNA essentially randomly into any target DNA without the aid of other factors. This concise review is focused on the advances in Tn5 applications in multi-omics technologies, genome-wide profiling, and Tn5 hybrid molecule creation. The possibilities of other transposase uses are also discussed.
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Affiliation(s)
- Dmitry Penkov
- IRCCS San Raffaele Hospital, 20132 Milan, Italy
- National Medical Research Centre of Cardiology Named after E. I. Chazov, 121552 Moscow, Russia
| | - Ekaterina Zubkova
- National Medical Research Centre of Cardiology Named after E. I. Chazov, 121552 Moscow, Russia
| | - Yelena Parfyonova
- National Medical Research Centre of Cardiology Named after E. I. Chazov, 121552 Moscow, Russia
- Faculty of Medicine, Lomonosov Moscow State University, 119991 Moscow, Russia
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2
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Constitutive Heterochromatin in Eukaryotic Genomes: A Mine of Transposable Elements. Cells 2022; 11:cells11050761. [PMID: 35269383 PMCID: PMC8909793 DOI: 10.3390/cells11050761] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/10/2022] [Accepted: 02/18/2022] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) are abundant components of constitutive heterochromatin of the most diverse evolutionarily distant organisms. TEs enrichment in constitutive heterochromatin was originally described in the model organism Drosophila melanogaster, but it is now considered as a general feature of this peculiar portion of the genomes. The phenomenon of TE enrichment in constitutive heterochromatin has been proposed to be the consequence of a progressive accumulation of transposable elements caused by both reduced recombination and lack of functional genes in constitutive heterochromatin. However, this view does not take into account classical genetics studies and most recent evidence derived by genomic analyses of heterochromatin in Drosophila and other species. In particular, the lack of functional genes does not seem to be any more a general feature of heterochromatin. Sequencing and annotation of Drosophila melanogaster constitutive heterochromatin have shown that this peculiar genomic compartment contains hundreds of transcriptionally active genes, generally larger in size than that of euchromatic ones. Together, these genes occupy a significant fraction of the genomic territory of heterochromatin. Moreover, transposable elements have been suggested to drive the formation of heterochromatin by recruiting HP1 and repressive chromatin marks. In addition, there are several pieces of evidence that transposable elements accumulation in the heterochromatin might be important for centromere and telomere structure. Thus, there may be more complexity to the relationship between transposable elements and constitutive heterochromatin, in that different forces could drive the dynamic of this phenomenon. Among those forces, preferential transposition may be an important factor. In this article, we present an overview of experimental findings showing cases of transposon enrichment into the heterochromatin and their positive evolutionary interactions with an impact to host genomes.
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3
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Wen W, Song S, Han Y, Chen H, Liu X, Qian Q. An efficient Screening System in Yeast to Select a Hyperactive piggyBac Transposase for Mammalian Applications. Int J Mol Sci 2020; 21:ijms21093064. [PMID: 32357554 PMCID: PMC7247424 DOI: 10.3390/ijms21093064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/15/2020] [Accepted: 04/24/2020] [Indexed: 12/31/2022] Open
Abstract
As non-viral transgenic vectors, the piggyBac transposon system represents an attractive tool for gene delivery to achieve a long-term gene expression in immunotherapy applications due to its large cargo capacity, its lack of a trace of transposon and of genotoxic potential, and its highly engineered structure. However, further improvements in transpose activity are required for industrialization and clinical applications. Herein, we established a one-plasmid effective screening system and a two-step high-throughput screening process in yeast to isolate hyperactive mutants for mammalian cell applications. By applying this screening system, 15 hyperactive piggyBac transposases that exhibited higher transpose activity compared with optimized hyPBase in yeast and four mutants that showed higher transpose activity in mammalian cells were selected among 3000 hyPBase mutants. The most hyperactive transposase, bz-hyPBase, with four mutation sites showed an ability to yield high-efficiency editing in Chinese hamster ovarian carcinoma (CHO) cells and T cells, indicating that they could be expanded for gene therapy approaches. Finally, we tested the potential of this screening system in other versions of piggyBac transposase.
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Affiliation(s)
- Wen Wen
- Shanghai Cell Therapy Research Institute, Shanghai 201805, China; (W.W.); (S.S.); (Y.H.); (H.C.)
- Shanghai Cell Therapy Group, Shanghai 201805, China
| | - Shanshan Song
- Shanghai Cell Therapy Research Institute, Shanghai 201805, China; (W.W.); (S.S.); (Y.H.); (H.C.)
- Shanghai Cell Therapy Group, Shanghai 201805, China
| | - Yuchun Han
- Shanghai Cell Therapy Research Institute, Shanghai 201805, China; (W.W.); (S.S.); (Y.H.); (H.C.)
- Shanghai Cell Therapy Group, Shanghai 201805, China
| | - Haibin Chen
- Shanghai Cell Therapy Research Institute, Shanghai 201805, China; (W.W.); (S.S.); (Y.H.); (H.C.)
- Shanghai Cell Therapy Group, Shanghai 201805, China
| | - Xiangzhen Liu
- Shanghai Cell Therapy Research Institute, Shanghai 201805, China; (W.W.); (S.S.); (Y.H.); (H.C.)
- Shanghai Cell Therapy Group, Shanghai 201805, China
- Correspondence: (X.L.); (Q.Q.); Tel.: +86-021-5959-3168
| | - Qijun Qian
- Shanghai Cell Therapy Research Institute, Shanghai 201805, China; (W.W.); (S.S.); (Y.H.); (H.C.)
- Shanghai Cell Therapy Group, Shanghai 201805, China
- Correspondence: (X.L.); (Q.Q.); Tel.: +86-021-5959-3168
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4
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Fischer K, Kind A, Schnieke A. Assembling multiple xenoprotective transgenes in pigs. Xenotransplantation 2018; 25:e12431. [PMID: 30055014 DOI: 10.1111/xen.12431] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/24/2018] [Accepted: 05/24/2018] [Indexed: 12/20/2022]
Abstract
This review gives a brief overview of the genetic modifications necessary for grafted porcine tissues and organs to overcome rejection in human recipients. It then focuses on the problem of generating and breeding herds of donor pigs carrying modified endogenous genes and multiple xenoprotective transgenes. A xenodonor pig optimised for human clinical use could well require the addition of ten or more xenoprotective transgenes. It is impractical to produce the required combination of transgene by cross-breeding animals bearing individual transgenes at unlinked genetic loci, because independent segregation means that huge numbers of pigs would be required to produce relatively few donor animals. A better approach is to colocate groups of transgenes at a single genomic locus. We outline current methods to assemble transgene arrays and consider their pros and cons. These include polycistronic expression systems, in vitro recombination of large DNA fragments in PAC and BAC vectors, transposon vectors, classical gene targeting by homologous recombination at permissive loci such as ROSA26, targeted transgene placement aided by gene editing systems such as CRISPR/Cas9, and transgene placement by site-specific recombination such as Min-tagging using the Bxb1recombinase.
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Affiliation(s)
- Konrad Fischer
- Chair of Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Alexander Kind
- Chair of Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Angelika Schnieke
- Chair of Livestock Biotechnology, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
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5
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Yum SY, Youn KY, Choi WJ, Jang G. Development of genome engineering technologies in cattle: from random to specific. J Anim Sci Biotechnol 2018; 9:16. [PMID: 29423215 PMCID: PMC5789629 DOI: 10.1186/s40104-018-0232-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 01/09/2018] [Indexed: 12/16/2022] Open
Abstract
The production of transgenic farm animals (e.g., cattle) via genome engineering for the gain or loss of gene functions is an important undertaking. In the initial stages of genome engineering, DNA micro-injection into one-cell stage embryos (zygotes) followed by embryo transfer into a recipient was performed because of the ease of the procedure. However, as this approach resulted in severe mosaicism and has a low efficiency, it is not typically employed in the cattle as priority, unlike in mice. To overcome the above issue with micro-injection in cattle, somatic cell nuclear transfer (SCNT) was introduced and successfully used to produce cloned livestock. The application of SCNT for the production of transgenic livestock represents a significant advancement, but its development speed is relatively slow because of abnormal reprogramming and low gene targeting efficiency. Recent genome editing technologies (e.g., ZFN, TALEN, and CRISPR-Cas9) have been rapidly adapted for applications in cattle and great results have been achieved in several fields such as disease models and bioreactors. In the future, genome engineering technologies will accelerate our understanding of genetic traits in bovine and will be readily adapted for bio-medical applications in cattle.
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Affiliation(s)
- Soo-Young Yum
- 1Department of Veterinary Clinical Science, College of Veterinary Medicine and the Research Institute of Veterinary Science, Seoul National University, Seoul, 08826 Republic of Korea
| | - Ki-Young Youn
- 1Department of Veterinary Clinical Science, College of Veterinary Medicine and the Research Institute of Veterinary Science, Seoul National University, Seoul, 08826 Republic of Korea
| | - Woo-Jae Choi
- 1Department of Veterinary Clinical Science, College of Veterinary Medicine and the Research Institute of Veterinary Science, Seoul National University, Seoul, 08826 Republic of Korea
| | - Goo Jang
- 1Department of Veterinary Clinical Science, College of Veterinary Medicine and the Research Institute of Veterinary Science, Seoul National University, Seoul, 08826 Republic of Korea.,2Farm Animal Clinical Training and Research Center, Institute of GreenBio Science Technology, Seoul National University, PyeongChang-Gun, Gangwon-do 25354 Republic of Korea.,3Emergence Center for Food-Medicine Personalized Therapy System, Advanced Institutes of Convergence Technology, Seoul National University, SuWon, Gyeonggi-do 16629 Republic of Korea.,4College of Veterinary Medicine, Seoul National University, #85, Room631, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
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6
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Yoshida J, Akagi K, Misawa R, Kokubu C, Takeda J, Horie K. Chromatin states shape insertion profiles of the piggyBac, Tol2 and Sleeping Beauty transposons and murine leukemia virus. Sci Rep 2017; 7:43613. [PMID: 28252665 PMCID: PMC5333637 DOI: 10.1038/srep43613] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 01/26/2017] [Indexed: 12/31/2022] Open
Abstract
DNA transposons and retroviruses are versatile tools in functional genomics and gene therapy. To facilitate their application, we conducted a genome-wide insertion site profiling of the piggyBac (PB), Tol2 and Sleeping Beauty (SB) transposons and the murine leukemia virus (MLV) in mouse embryonic stem cells (ESCs). PB and MLV preferred highly expressed genes, whereas Tol2 and SB preferred weakly expressed genes. However, correlations with DNase I hypersensitive sites were different for all vectors, indicating that chromatin accessibility is not the sole determinant. Therefore, we analysed various chromatin states. PB and MLV highly correlated with Cohesin, Mediator and ESC-specific transcription factors. Notably, CTCF sites were correlated with PB but not with MLV, suggesting MLV prefers smaller promoter-enhancer loops, whereas PB insertion encompasses larger chromatin loops termed topologically associating domains. Tol2 also correlated with Cohesin and CTCF. However, correlations with ESC-specific transcription factors were weaker, suggesting that Tol2 prefers transcriptionally weak chromatin loops. Consistently, Tol2 insertions were associated with bivalent histone modifications characteristic of silent and inducible loci. SB showed minimum preference to all chromatin states, suggesting the least adverse effect on adjacent genes. These results will be useful for vector selection for various applications.
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Affiliation(s)
- Junko Yoshida
- Department of Physiology II, Nara Medical University, Kashihara, Nara 634-8521, Japan.,Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Keiko Akagi
- Comprehensive Cancer Center, Ohio State University, Columbus, Ohio 43210, USA
| | - Ryo Misawa
- 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
| | - Junji Takeda
- 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.,Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.,Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
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7
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Housden BE, Muhar M, Gemberling M, Gersbach CA, Stainier DYR, Seydoux G, Mohr SE, Zuber J, Perrimon N. Loss-of-function genetic tools for animal models: cross-species and cross-platform differences. Nat Rev Genet 2016; 18:24-40. [PMID: 27795562 DOI: 10.1038/nrg.2016.118] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Our understanding of the genetic mechanisms that underlie biological processes has relied extensively on loss-of-function (LOF) analyses. LOF methods target DNA, RNA or protein to reduce or to ablate gene function. By analysing the phenotypes that are caused by these perturbations the wild-type function of genes can be elucidated. Although all LOF methods reduce gene activity, the choice of approach (for example, mutagenesis, CRISPR-based gene editing, RNA interference, morpholinos or pharmacological inhibition) can have a major effect on phenotypic outcomes. Interpretation of the LOF phenotype must take into account the biological process that is targeted by each method. The practicality and efficiency of LOF methods also vary considerably between model systems. We describe parameters for choosing the optimal combination of method and system, and for interpreting phenotypes within the constraints of each method.
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Affiliation(s)
- Benjamin E Housden
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
| | - Matthias Muhar
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Matthew Gemberling
- Department of Biomedical Engineering and the Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA
| | - Charles A Gersbach
- Department of Biomedical Engineering and the Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708, USA
| | - Didier Y R Stainier
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, 43 Ludwigstrasse, Bad Nauheim 61231, Germany
| | - Geraldine Seydoux
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21218, USA.,Howard Hughes Medical Institute, 725 North Wolfe Street, Baltimore, Maryland 21218, USA
| | - Stephanie E Mohr
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA.,Howard Hughes Medical Institute, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
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8
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Bii VM, Trobridge GD. Identifying Cancer Driver Genes Using Replication-Incompetent Retroviral Vectors. Cancers (Basel) 2016; 8:cancers8110099. [PMID: 27792127 PMCID: PMC5126759 DOI: 10.3390/cancers8110099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 12/16/2022] Open
Abstract
Identifying novel genes that drive tumor metastasis and drug resistance has significant potential to improve patient outcomes. High-throughput sequencing approaches have identified cancer genes, but distinguishing driver genes from passengers remains challenging. Insertional mutagenesis screens using replication-incompetent retroviral vectors have emerged as a powerful tool to identify cancer genes. Unlike replicating retroviruses and transposons, replication-incompetent retroviral vectors lack additional mutagenesis events that can complicate the identification of driver mutations from passenger mutations. They can also be used for almost any human cancer due to the broad tropism of the vectors. Replication-incompetent retroviral vectors have the ability to dysregulate nearby cancer genes via several mechanisms including enhancer-mediated activation of gene promoters. The integrated provirus acts as a unique molecular tag for nearby candidate driver genes which can be rapidly identified using well established methods that utilize next generation sequencing and bioinformatics programs. Recently, retroviral vector screens have been used to efficiently identify candidate driver genes in prostate, breast, liver and pancreatic cancers. Validated driver genes can be potential therapeutic targets and biomarkers. In this review, we describe the emergence of retroviral insertional mutagenesis screens using replication-incompetent retroviral vectors as a novel tool to identify cancer driver genes in different cancer types.
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Affiliation(s)
- Victor M Bii
- College of Pharmacy, Washington State University, WSU Spokane PBS 323, P.O. Box 1495, Spokane, WA 99210, USA.
| | - Grant D Trobridge
- College of Pharmacy, Washington State University, WSU Spokane PBS 323, P.O. Box 1495, Spokane, WA 99210, USA.
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA.
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9
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Cheng JK, Lewis AM, Kim DS, Dyess T, Alper HS. Identifying and retargeting transcriptional hot spots in the human genome. Biotechnol J 2016; 11:1100-9. [PMID: 27311394 DOI: 10.1002/biot.201600015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 05/18/2016] [Accepted: 05/30/2016] [Indexed: 01/17/2023]
Abstract
Mammalian cell line development requires streamlined methodologies that will reduce both the cost and time to identify candidate cell lines. Improvements in site-specific genomic editing techniques can result in flexible, predictable, and robust cell line engineering. However, an outstanding question in the field is the specific site of integration. Here, we seek to identify productive loci within the human genome that will result in stable, high expression of heterologous DNA. Using an unbiased, random integration approach and a green fluorescent reporter construct, we identify ten single-integrant, recombinant human cell lines that exhibit stable, high-level expression. From these cell lines, eight unique corresponding integration loci were identified. These loci are concentrated in non-protein coding regions or intronic regions of protein coding genes. Expression mapping of the surrounding genes reveals minimal disruption of endogenous gene expression. Finally, we demonstrate that targeted de novo integration at one of the identified loci, the 12(th) exon-intron region of the GRIK1 gene on chromosome 21, results in superior expression and stability compared to the standard, illegitimate integration approach at levels approaching 4-fold. The information identified here along with recent advances in site-specific genomic editing techniques can lead to expedited cell line development.
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Affiliation(s)
- Joseph K Cheng
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Amanda M Lewis
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA.,Biologics Development, Bristol-Myers Squibb, Devens, MA, USA
| | - Do Soon Kim
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Timothy Dyess
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Hal S Alper
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA. .,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA.
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10
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Alessio AP, Fili AE, Garrels W, Forcato DO, Olmos Nicotra MF, Liaudat AC, Bevacqua RJ, Savy V, Hiriart MI, Talluri TR, Owens JB, Ivics Z, Salamone DF, Moisyadi S, Kues WA, Bosch P. Establishment of cell-based transposon-mediated transgenesis in cattle. Theriogenology 2015; 85:1297-311.e2. [PMID: 26838464 DOI: 10.1016/j.theriogenology.2015.12.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/10/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022]
Abstract
Transposon-mediated transgenesis is a well-established tool for genome modification in small animal models. However, translation of this active transgenic method to large animals warrants further investigations. Here, the piggyBac (PB) and sleeping beauty (SB) transposon systems were assessed for stable gene transfer into the cattle genome. Bovine fibroblasts were transfected either with a helper-independent PB system or a binary SB system. Both transposons were highly active in bovine cells increasing the efficiency of DNA integration up to 88 times over basal nonfacilitated integrations in a colony formation assay. SB transposase catalyzed multiplex transgene integrations in fibroblast cells transfected with the helper vector and two donor vectors carrying different transgenes (fluorophore and neomycin resistance). Stably transfected fibroblasts were used for SCNT and on in vitro embryo culture, morphologically normal blastocysts that expressed the fluorophore were obtained with both transposon systems. The data indicate that transposition is a feasible approach for genetic engineering in the cattle genome.
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Affiliation(s)
- Ana P Alessio
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, República Argentina
| | - Alejandro E Fili
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, República Argentina
| | - Wiebke Garrels
- Department of Biotechnology, Friedrich-Loeffler-Institut, Institut für Nutztiergenetik, Neustadt, Germany
| | - Diego O Forcato
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, República Argentina
| | - María F Olmos Nicotra
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, República Argentina
| | - Ana C Liaudat
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, República Argentina
| | - Romina J Bevacqua
- Laboratorio de Biotecnología Animal, Departamento de Producción Animal, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, República Argentina
| | - Virginia Savy
- Laboratorio de Biotecnología Animal, Departamento de Producción Animal, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, República Argentina
| | - María I Hiriart
- Laboratorio de Biotecnología Animal, Departamento de Producción Animal, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, República Argentina
| | - Thirumala R Talluri
- Department of Biotechnology, Friedrich-Loeffler-Institut, Institut für Nutztiergenetik, Neustadt, Germany
| | - Jesse B Owens
- Department of Anatomy, Biochemistry and Physiology, Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul-Ehrlich-Institute, Langen, Germany
| | - Daniel F Salamone
- Laboratorio de Biotecnología Animal, Departamento de Producción Animal, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, República Argentina
| | - Stefan Moisyadi
- Department of Anatomy, Biochemistry and Physiology, Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Wilfried A Kues
- Department of Biotechnology, Friedrich-Loeffler-Institut, Institut für Nutztiergenetik, Neustadt, Germany
| | - Pablo Bosch
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, República Argentina.
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11
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Bosch P, Forcato DO, Alustiza FE, Alessio AP, Fili AE, Olmos Nicotra MF, Liaudat AC, Rodríguez N, Talluri TR, Kues WA. Exogenous enzymes upgrade transgenesis and genetic engineering of farm animals. Cell Mol Life Sci 2015; 72:1907-29. [PMID: 25636347 PMCID: PMC11114025 DOI: 10.1007/s00018-015-1842-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 01/14/2023]
Abstract
Transgenic farm animals are attractive alternative mammalian models to rodents for the study of developmental, genetic, reproductive and disease-related biological questions, as well for the production of recombinant proteins, or the assessment of xenotransplants for human patients. Until recently, the ability to generate transgenic farm animals relied on methods of passive transgenesis. In recent years, significant improvements have been made to introduce and apply active techniques of transgenesis and genetic engineering in these species. These new approaches dramatically enhance the ease and speed with which livestock species can be genetically modified, and allow to performing precise genetic modifications. This paper provides a synopsis of enzyme-mediated genetic engineering in livestock species covering the early attempts employing naturally occurring DNA-modifying proteins to recent approaches working with tailored enzymatic systems.
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Affiliation(s)
- Pablo Bosch
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Diego O. Forcato
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Fabrisio E. Alustiza
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Ana P. Alessio
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Alejandro E. Fili
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - María F. Olmos Nicotra
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Ana C. Liaudat
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Nancy Rodríguez
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Fco-Qcas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba Republic of Argentina
| | - Thirumala R. Talluri
- Friedrich-Loeffler-Institute, Institute of Farm Animal Genetics, Biotechnology, 31535 Neustadt, Germany
| | - Wilfried A. Kues
- Friedrich-Loeffler-Institute, Institute of Farm Animal Genetics, Biotechnology, 31535 Neustadt, Germany
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Exploiting the power of LINE-1 retrotransposon mutagenesis for identification of genes involved in embryonic stem cell differentiation. Stem Cell Rev Rep 2014; 10:408-16. [PMID: 24610122 PMCID: PMC4008784 DOI: 10.1007/s12015-014-9500-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Identifying the genes or epigenetic factors that control the self-renewal and differentiation of stem cells is critical to understanding the molecular basis of cell commitment. Although a number of insertional mutagenesis vectors have been developed for identifying gene functions in animal models, the L1 retrotransposition system offers additional advantages as a tool to disrupt genes in embryonic stem cells in order to identify their functions and the phenotypes associated with them. Recent advances in producing synthetic versions of L1 retrotransposon vector system and the optimization of techniques to accurately identify retrotransposon integration sites have increased their utility for gene discovery applications. We have developed a novel episomal, nonviral L1 retrotransposon vector using scaffold/matrix attachment regions that provides stable, sustained levels of retrotransposition in cell cultures without being affected by epigenetic silencing or from some of the common problems of vector integration. This modified vector contains a GFP marker whose expression occurs only after successful gene disruption events and thus the cells with disrupted genes can be easily picked for functional analysis. Here we present a method to disrupt gene function in embryonic stem cells that aid in the identification of genes involved in stem cell differentiation processes. The methods presented here can be easily adapted to the study of other types of cancer stem cells or induced pluripotent stem cells using the L1 retrotransposon as an insertional mutagen.
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Marakli S, Yilmaz S, Gozukirmizi N. BARE1andBAGY2Retrotransposon Movements and Expression Analyses in Developing Barley Seedlings. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/bbeq.2012.0112] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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14
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Skipper KA, Andersen PR, Sharma N, Mikkelsen JG. DNA transposon-based gene vehicles - scenes from an evolutionary drive. J Biomed Sci 2013; 20:92. [PMID: 24320156 PMCID: PMC3878927 DOI: 10.1186/1423-0127-20-92] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/27/2013] [Indexed: 12/12/2022] Open
Abstract
DNA transposons are primitive genetic elements which have colonized living organisms from plants to bacteria and mammals. Through evolution such parasitic elements have shaped their host genomes by replicating and relocating between chromosomal loci in processes catalyzed by the transposase proteins encoded by the elements themselves. DNA transposable elements are constantly adapting to life in the genome, and self-suppressive regulation as well as defensive host mechanisms may assist in buffering ‘cut-and-paste’ DNA mobilization until accumulating mutations will eventually restrict events of transposition. With the reconstructed Sleeping Beauty DNA transposon as a powerful engine, a growing list of transposable elements with activity in human cells have moved into biomedical experimentation and preclinical therapy as versatile vehicles for delivery and genomic insertion of transgenes. In this review, we aim to link the mechanisms that drive transposon evolution with the realities and potential challenges we are facing when adapting DNA transposons for gene transfer. We argue that DNA transposon-derived vectors may carry inherent, and potentially limiting, traits of their mother elements. By understanding in detail the evolutionary journey of transposons, from host colonization to element multiplication and inactivation, we may better exploit the potential of distinct transposable elements. Hence, parallel efforts to investigate and develop distinct, but potent, transposon-based vector systems will benefit the broad applications of gene transfer. Insight and clever optimization have shaped new DNA transposon vectors, which recently debuted in the first DNA transposon-based clinical trial. Learning from an evolutionary drive may help us create gene vehicles that are safer, more efficient, and less prone for suppression and inactivation.
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Affiliation(s)
| | | | | | - Jacob Giehm Mikkelsen
- Department of Biomedicine, Aarhus University, Wilh, Meyers Allé 4, DK-8000, Aarhus C, Denmark.
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15
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Jursch T, Miskey C, Izsvák Z, Ivics Z. Regulation of DNA transposition by CpG methylation and chromatin structure in human cells. Mob DNA 2013; 4:15. [PMID: 23676100 PMCID: PMC3680223 DOI: 10.1186/1759-8753-4-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 04/19/2013] [Indexed: 12/25/2022] Open
Abstract
Background The activity of transposable elements can be regulated by different means. DNA CpG methylation is known to decrease or inhibit transpositional activity of diverse transposons. However, very surprisingly, it was previously shown that CpG methylation of the Sleeping Beauty (SB) transposon significantly enhanced transposition in mouse embryonic stem cells. Results In order to investigate the unexpected response of SB transposition to CpG methylation, related transposons from the Tc1/mariner superfamily, that is, Tc1, Himar1, Hsmar1, Frog Prince (FP) and Minos were tested to see how transposition was affected by CpG methylation. A significant increase of >20-fold in transposition of SB, FP and Minos was seen, whereas Tc1, Himar1 and Hsmar1 showed no difference in transposition upon CpG-methylation. The terminal inverted repeats (TIRs) of the SB, FP and Minos elements share a common structure, in which each TIR contains two functionally important binding sites for the transposase (termed the IR/DR structure). The group of IR/DR elements showed increased excision after CpG methylation compared to untreated transposon donor plasmids. We found that de novo CpG methylation is not required for transposition. A mutated FP donor plasmid with depleted CpG sites in both TIRs was as efficient in transposition as the wild-type transposon, indicating that CpG sites inside the TIRs are not responsible for altered binding of factors potentially modulating transposition. By using an in vivo one-hybrid DNA-binding assay in cultured human cells we found that CpG methylation had no appreciable effect on the affinity of SB transposase to its binding sites. However, chromatin immunoprecipitation indicated that CpG-methylated transposon donor plasmids are associated with a condensed chromatin structure characterized by trimethylated histone H3K9. Finally, DNA compaction by protamine was found to enhance SB transposition. Conclusions We have shown that DNA CpG methylation upregulates transposition of IR/DR elements in the Tc1/mariner superfamily. CpG methylation provokes the formation of a tight chromatin structure at the transposon DNA, likely aiding the formation of a catalytically active complex by facilitating synapsis of sites bound by the transposase.
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Affiliation(s)
- Tobias Jursch
- Max Delbrück Center for Molecular Medicine, D-13125, Berlin, Germany.
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16
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The piggyBac transposon displays local and distant reintegration preferences and can cause mutations at noncanonical integration sites. Mol Cell Biol 2013; 33:1317-30. [PMID: 23358416 DOI: 10.1128/mcb.00670-12] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The DNA transposon piggyBac is widely used as a tool in mammalian experimental systems for transgenesis, mutagenesis, and genome engineering. We have characterized genome-wide insertion site preferences of piggyBac by sequencing a large set of integration sites arising from transposition from two separate genomic loci and a plasmid donor in mouse embryonic stem cells. We found that piggyBac preferentially integrates locally to the excision site when mobilized from a chromosomal location and identified other nonlocal regions of the genome with elevated insertion frequencies. piggyBac insertions were associated with expressed genes and markers of open chromatin structure and were excluded from heterochromatin. At the nucleotide level, piggyBac prefers to insert into TA-rich regions within a broader GC-rich context. We also found that piggyBac can insert into sites other than its known TTAA insertion site at a low frequency (2%). Such insertions introduce mismatches that are repaired with signatures of host cell repair pathways. Transposons could be mobilized from plasmids with the observed noncanonical flanking regions, indicating that piggyBac could generate point mutations in the genome.
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17
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Pujolar JM, Astolfi L, Boscari E, Vidotto M, Barbisan F, Bruson A, Congiu L. Tana1, a new putatively active Tc1-like transposable element in the genome of sturgeons. Mol Phylogenet Evol 2012; 66:223-32. [PMID: 23032571 DOI: 10.1016/j.ympev.2012.09.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/21/2012] [Accepted: 09/23/2012] [Indexed: 01/05/2023]
Abstract
We report the discovery of a new putatively active Tc1-like transposable element (Tana1) in the genome of sturgeons, an ancient group of fish considered as living fossils. The complete sequence of Tana1 was first characterized in the 454-sequenced transcriptome of the Adriatic sturgeon (Acipenser naccarii) and then isolated from the genome of the same species and from 12 additional sturgeons including three genera of the Acipenseridae (Acipenser, Huso, Scaphirhynchus). The element has a total length of 1588bp and presents inverted repeats of 210bp, one of which partially overlapping the 3' region of the transposase gene. The spacing of the DDE motif within the catalytic domain in Tana1 is unique (DD38E) and indicates that Tana1 can be considered as the first representative of a new Tc1 subfamily. The integrity of the native form (with no premature termination codons within the transposase), the presence of all expected functional domains and its occurrence in the sturgeon transcriptome suggest a current or recent activity of Tana1. The presence of Tana1 in the genome of the 13 sturgeon species in our study points to an ancient origin of the element that existed before the split of the group 170 million years ago. The dissemination of Tana1 across sturgeon genomes could be interpreted by postulating vertical transmission from an ancestral Tana1 with a particularly slow evolutionary rate Horizontal transmission might have also played a role in the dissemination of Tana1 as evidenced by the presence of a complete copy in the genome of Atlantic salmon. Vertical and horizontal transmission are not mutually exclusive and may have concurred in shaping the evolution of Tana1.
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18
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Remobilization of Sleeping Beauty transposons in the germline of Xenopus tropicalis. Mob DNA 2011; 2:15. [PMID: 22115366 PMCID: PMC3271037 DOI: 10.1186/1759-8753-2-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 11/24/2011] [Indexed: 12/03/2022] Open
Abstract
Background The Sleeping Beauty (SB) transposon system has been used for germline transgenesis of the diploid frog, Xenopus tropicalis. Injecting one-cell embryos with plasmid DNA harboring an SB transposon substrate together with mRNA encoding the SB transposase enzyme resulted in non-canonical integration of small-order concatemers of the transposon. Here, we demonstrate that SB transposons stably integrated into the frog genome are effective substrates for remobilization. Results Transgenic frogs that express the SB10 transposase were bred with SB transposon-harboring animals to yield double-transgenic 'hopper' frogs. Remobilization events were observed in the progeny of the hopper frogs and were verified by Southern blot analysis and cloning of the novel integrations sites. Unlike the co-injection method used to generate founder lines, transgenic remobilization resulted in canonical transposition of the SB transposons. The remobilized SB transposons frequently integrated near the site of the donor locus; approximately 80% re-integrated with 3 Mb of the donor locus, a phenomenon known as 'local hopping'. Conclusions In this study, we demonstrate that SB transposons integrated into the X. tropicalis genome are effective substrates for excision and re-integration, and that the remobilized transposons are transmitted through the germline. This is an important step in the development of large-scale transposon-mediated gene- and enhancer-trap strategies in this highly tractable developmental model system.
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19
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Retrotransposon-induced heterochromatin spreading in the mouse revealed by insertional polymorphisms. PLoS Genet 2011; 7:e1002301. [PMID: 21980304 PMCID: PMC3183085 DOI: 10.1371/journal.pgen.1002301] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 08/04/2011] [Indexed: 12/13/2022] Open
Abstract
The "arms race" relationship between transposable elements (TEs) and their host has promoted a series of epigenetic silencing mechanisms directed against TEs. Retrotransposons, a class of TEs, are often located in repressed regions and are thought to induce heterochromatin formation and spreading. However, direct evidence for TE-induced local heterochromatin in mammals is surprisingly scarce. To examine this phenomenon, we chose two mouse embryonic stem (ES) cell lines that possess insertionally polymorphic retrotransposons (IAP, ETn/MusD, and LINE elements) at specific loci in one cell line but not the other. Employing ChIP-seq data for these cell lines, we show that IAP elements robustly induce H3K9me3 and H4K20me3 marks in flanking genomic DNA. In contrast, such heterochromatin is not induced by LINE copies and only by a minority of polymorphic ETn/MusD copies. DNA methylation is independent of the presence of IAP copies, since it is present in flanking regions of both full and empty sites. Finally, such spreading into genes appears to be rare, since the transcriptional start sites of very few genes are less than one Kb from an IAP. However, the B3galtl gene is subject to transcriptional silencing via IAP-induced heterochromatin. Hence, although rare, IAP-induced local heterochromatin spreading into nearby genes may influence expression and, in turn, host fitness.
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20
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Abstract
DNA transposons have been widely used for transgenesis and insertional mutagenesis in various organisms. Among the transposons active in mammalian cells, the moth-derived transposon piggyBac is most promising with its highly efficient transposition, large cargo capacity, and precise repair of the donor site. Here we report the generation of a hyperactive piggyBac transposase. The active transposition of piggyBac in multiple organisms allowed us to screen a transposase mutant library in yeast for hyperactive mutants and then to test candidates in mouse ES cells. We isolated 18 hyperactive mutants in yeast, among which five were also hyperactive in mammalian cells. By combining all mutations, a total of 7 aa substitutions, into a single reading frame, we generated a unique hyperactive piggyBac transposase with 17-fold and ninefold increases in excision and integration, respectively. We showed its applicability by demonstrating an increased efficiency of generation of transgene-free mouse induced pluripotent stem cells. We also analyzed whether this hyperactive piggyBac transposase affects the genomic integrity of the host cells. The frequency of footprints left by the hyperactive piggyBac transposase was as low as WT transposase (~1%) and we found no evidence that the expression of the transposase affects genomic integrity. This hyperactive piggyBac transposase expands the utility of the piggyBac transposon for applications in mammalian genetics and gene therapy.
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21
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Bjork BC, Fujiwara Y, Davis SW, Qiu H, Saunders TL, Sandy P, Orkin S, Camper SA, Beier DR. A transient transgenic RNAi strategy for rapid characterization of gene function during embryonic development. PLoS One 2010; 5:e14375. [PMID: 21179568 PMCID: PMC3002952 DOI: 10.1371/journal.pone.0014375] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 11/24/2010] [Indexed: 01/14/2023] Open
Abstract
RNA interference (RNAi) is a powerful strategy for studying the phenotypic consequences of reduced gene expression levels in model systems. To develop a method for the rapid characterization of the developmental consequences of gene dysregulation, we tested the use of RNAi for “transient transgenic” knockdown of mRNA in mouse embryos. These methods included lentiviral infection as well as transposition using the Sleeping Beauty (SB) and PiggyBac (PB) transposable element systems. This approach can be useful for phenotypic validation of putative mutant loci, as we demonstrate by confirming that knockdown of Prdm16 phenocopies the ENU-induced cleft palate (CP) mutant, csp1. This strategy is attractive as an alternative to gene targeting in embryonic stem cells, as it is simple and yields phenotypic information in a matter of weeks. Of the three methodologies tested, the PB transposon system produced high numbers of transgenic embryos with the expected phenotype, demonstrating its utility as a screening method.
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Affiliation(s)
- Bryan C. Bjork
- Genetics Division, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yuko Fujiwara
- Division of Hematology and Oncology, Children's Hospital, Harvard Medical School/Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Shannon W. Davis
- Departments of Human Genetics and Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Haiyan Qiu
- Genetics Division, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thomas L. Saunders
- Departments of Human Genetics and Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Peter Sandy
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Stuart Orkin
- Division of Hematology and Oncology, Children's Hospital, Harvard Medical School/Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Sally A. Camper
- Departments of Human Genetics and Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - David R. Beier
- Genetics Division, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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22
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Abstract
Recently, it has become possible to mobilize the Tc1/mariner transposon, Sleeping Beauty (SB), in mouse somatic cells at frequencies high enough to induce cancer. Tumours result from SB insertional mutagenesis of cancer genes, thus facilitating the identification of the genes and signalling pathways that drive tumour formation. A conditional SB transposition system has also been developed that makes it possible to limit where SB mutagenesis occurs, providing a means to selectively model many types of human cancer. SB mutagenesis has already identified a large collection of known cancer genes in addition to a plethora of new candidate cancer genes and potential drug targets.
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Affiliation(s)
- Neal G Copeland
- Genomics and Genetics Division, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, 61 Biopolis Drive, Proteos, Singapore 138673
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23
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Rangasamy D. An S/MAR-based L1 retrotransposition cassette mediates sustained levels of insertional mutagenesis without suffering from epigenetic silencing of DNA methylation. Epigenetics 2010; 5:601-11. [PMID: 20595816 DOI: 10.4161/epi.5.7.12647] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
L1 is an insertional mutagen that is capable of mediating permanent gene disruption in mammalian genomes. However, currently available L1 retrotransposition vectors exhibit low or unstable transgene expression when expressed in somatic cells and tissues. This restriction limits their potential utility in long-term screening procedures or somatic mutagenesis applications. In this study, we addressed this problem by developing a minicircle, nonviral L1 retrotransposition vector using a scaffold/matrix attachment region (S/MAR) in the vector backbone and evaluated its utility in human cell lines. The S/MAR-based L1 retrotransposition vector provides stable, elevated levels of L1 expression compared to the currently used EBNA1-based L1 vector. In addition, the S/MAR elements effectively mediate sustained levels of L1 retrotransposition in prolonged cell culturing without suffering from epigenetic silencing by DNA methylation or from vector integration problems even in the absence of selection pressure. These findings indicate that the simple inclusion of S/MAR in the vector backbone increased levels of L1 expression and retrotransposition that can be used as an effective tool to generate insertional mutagenesis in large-scale somatic mutagenesis applications in mammalian cells.
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Affiliation(s)
- Danny Rangasamy
- The John Curtin School of Medical Research, Australian National University, Canberra, Australia.
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24
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Muñoz-López M, García-Pérez JL. DNA transposons: nature and applications in genomics. Curr Genomics 2010; 11:115-28. [PMID: 20885819 PMCID: PMC2874221 DOI: 10.2174/138920210790886871] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 11/18/2009] [Accepted: 12/01/2009] [Indexed: 12/19/2022] Open
Abstract
Repeated DNA makes up a large fraction of a typical mammalian genome, and some repetitive elements are able to move within the genome (transposons and retrotransposons). DNA transposons move from one genomic location to another by a cut-and-paste mechanism. They are powerful forces of genetic change and have played a significant role in the evolution of many genomes. As genetic tools, DNA transposons can be used to introduce a piece of foreign DNA into a genome. Indeed, they have been used for transgenesis and insertional mutagenesis in different organisms, since these elements are not generally dependent on host factors to mediate their mobility. Thus, DNA transposons are useful tools to analyze the regulatory genome, study embryonic development, identify genes and pathways implicated in disease or pathogenesis of pathogens, and even contribute to gene therapy. In this review, we will describe the nature of these elements and discuss recent advances in this field of research, as well as our evolving knowledge of the DNA transposons most widely used in these studies.
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Affiliation(s)
- Martín Muñoz-López
- Andalusian Stem Cell Bank, Center for Biomedical Research, University of Granada, Avda. del Conocimiento s/n, Armilla, 18100, Granada, Spain
| | - José L. García-Pérez
- Andalusian Stem Cell Bank, Center for Biomedical Research, University of Granada, Avda. del Conocimiento s/n, Armilla, 18100, Granada, Spain
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25
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Cheng CY, Vogt A, Mochizuki K, Yao MC. A domesticated piggyBac transposase plays key roles in heterochromatin dynamics and DNA cleavage during programmed DNA deletion in Tetrahymena thermophila. Mol Biol Cell 2010; 21:1753-62. [PMID: 20357003 PMCID: PMC2869380 DOI: 10.1091/mbc.e09-12-1079] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This study suggests that a TPB2 piggyBac transposase has evolved to facilitate heterochromatin assembly and carry out the final DNA excision step of programmed DNA deletion in Tetrahymena thermophila. TPB2 appears to have gone through a domestication process to become a host gene and be maintained in the macronuclear genome. Transposons comprise large fractions of eukaryotic genomes and provide genetic reservoirs for the evolution of new cellular functions. We identified TPB2, a homolog of the piggyBac transposase gene that is required for programmed DNA deletion in Tetrahymena. TPB2 was expressed exclusively during the time of DNA excision, and its encoded protein Tpb2p was localized in DNA elimination heterochromatin structures. Notably, silencing of TPB2 by RNAi disrupts the final assembly of these heterochromatin structures and prevents DNA deletion to occur. In vitro studies revealed that Tpb2p is an endonuclease that produces double-strand breaks with four-base 5′ protruding ends, similar to the ends generated during DNA deletion. These findings suggest that Tpb2p plays a key role in the assembly of specialized DNA elimination chromatin architectures and is likely responsible for the DNA cleavage step of programmed DNA deletion.
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Affiliation(s)
- Chao-Yin Cheng
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
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26
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Carlson DF, Geurts AM, Garbe JR, Park CW, Rangel-Filho A, O'Grady SM, Jacob HJ, Steer CJ, Largaespada DA, Fahrenkrug SC. Efficient mammalian germline transgenesis by cis-enhanced Sleeping Beauty transposition. Transgenic Res 2010; 20:29-45. [PMID: 20352328 DOI: 10.1007/s11248-010-9386-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Accepted: 03/11/2010] [Indexed: 01/18/2023]
Abstract
Heightened interest in relevant models for human disease increases the need for improved methods for germline transgenesis. We describe a significant improvement in the creation of transgenic laboratory mice and rats by chemical modification of Sleeping Beauty transposons. Germline transgenesis in mice and rats was significantly enhanced by in vitro cytosine-phosphodiester-guanine methylation of transposons prior to injection. Heritability of transgene alleles was also greater from founder mice generated with methylated versus non-methylated transposon. The artificial methylation was reprogrammed in the early embryo, leading to founders that express the transgenes. We also noted differences in transgene insertion number and structure (single-insert versus concatemer) based on the influence of methylation and plasmid conformation (linear versus supercoiled), with supercoiled substrate resulting in efficient transpositional transgenesis (TnT) with near elimination of concatemer insertion. Combined, these substrate modifications resulted in increases in both the frequency of transgenic founders and the number of transgenes per founder, significantly elevating the number of potential transgenic lines. Given its simplicity, versatility and high efficiency, TnT with enhanced Sleeping Beauty components represents a compelling non-viral approach to modifying the mammalian germline.
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27
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Cloning of triose phosphate isomerase gene from an antarctic psychrophilic Pseudomonas sp. by degenerate and splinkerette PCR. World J Microbiol Biotechnol 2010; 26:1251-9. [PMID: 24026930 DOI: 10.1007/s11274-009-0295-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
Abstract
Psychrophiles are organisms that thrive in cold environments. One of the strategies for their cold adaptation is the ability to synthesize cold-adapted enzymes. These enzymes usually display higher catalytic efficiency and thermolability at lower temperatures compared to their mesophilic and thermophilic counterparts. In this work, a psychrophilic bacterial isolate codenamed π9 was selected for the cloning of the gene encoding triose phosphate isomerase (TIM), an enzyme in the glycolytic pathway. Based on 16S rRNA gene sequence analysis, this isolate was identified as a species of the genus Pseudomonas under the P. fluorescens group. The cloning of a 816 bp fragment of TIM gene which covers the 756 bp open reading frame was achieved by a combination of degenerate and splinkerette PCRs. The partial sequence of this gene was first PCR amplified by using degenerate primers and the flanking sequences were subsequently amplified by splinkerette PCR technique. Amino acid sequence of the cloned TIM was 97% identical to TIM from Pseudomonas fluorescens and shared 51% identity with the TIM from psychrophilic Vibrio sp. This work demonstrated the use of multiple PCR techniques to clone a gene without prior knowledge of its sequence. The cloning of the TIM gene by PCR was more rapid and cost effective compared to the traditional genomic library construction and screening method. Homology model of the TIM protein in this study was generated based on Escherichia coli TIM crystal structure. The model could serve as a hypothetical TIM structure from a psychrophilic microorganism for further investigation into areas that showed deviations from the known mesophilic TIM structures.
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28
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Abstract
The resurrection of the Sleeping Beauty (SB) transposon from molecularly extinct salmonid transposons at the end of last century opened the door for mouse geneticists to develop various transposon-based genetic tool kits, which had already been proven instrumental in Drosophila and other invertebrate model organisms. Since then, transposon technologies have been successfully applied to many aspects of functional genomics, in combination with various well-established tools of mouse genetics including transgenesis and gene targeting. In the SB system, a substantial fraction of the transposition events occurs on the same chromosome, predominantly within 3-4 megabases, while the remainder occurs between different chromosomes in a genome-wide manner. By taking advantage of the two types of transposition, we have developed applications of the SB system for genome-wide mutagenesis as well as region-specific functional analysis of the mouse genome.
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29
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Díaz-González J, Domínguez A, Albornoz J. Genomic distribution of retrotransposons 297, 1731, copia, mdg1 and roo in the Drosophila melanogaster species subgroup. Genetica 2009; 138:579-86. [PMID: 20012466 DOI: 10.1007/s10709-009-9430-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 12/01/2009] [Indexed: 10/20/2022]
Abstract
The intragenomic distribution of five retrotransposon families (297, 1731, copia, mdg1 and roo) in the species of the melanogaster complex was studied by comparing results of the Southern blotting technique in males and females with those of in situ hybridization. The degree of structural polymorphism of each family in the different species was also investigated by restriction enzyme analysis. It was found that genomic distribution is a trait that depends on the family and species. The distribution of roo is mainly euchromatic in the four species and 1731 is heterochromatic, but the distribution of families 297, copia and mdg1 is markedly different in the melanogaster and simulans clades. These families were mainly euchromatic in D. melanogaster but heterochromatic in its sibling species. In the simulans clade most copia and mdg1 elements are located on chromosome Y. Differences in genomic distribution are unrelated with structural conservation. The relation of intragenomic distribution to phylogeny, transpositional activity and the role of the host genome are discussed.
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Affiliation(s)
- Julia Díaz-González
- Area de Genética, Departamento de Biología Funcional, Universidad de Oviedo, 33071, Oviedo, Spain
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A transposon-based chromosomal engineering method to survey a large cis-regulatory landscape in mice. Nat Genet 2009; 41:946-52. [DOI: 10.1038/ng.397] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 05/12/2009] [Indexed: 11/08/2022]
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31
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Crénès G, Moundras C, Demattei MV, Bigot Y, Petit A, Renault S. Target site selection by the mariner-like element, Mos1. Genetica 2009; 138:509-17. [PMID: 19629719 DOI: 10.1007/s10709-009-9387-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 07/07/2009] [Indexed: 12/18/2022]
Abstract
The eukaryotic transposon Mos1 is a class-II transposable element that moves using a "cut-and-paste" mechanism in which the transposase is the only protein factor required. The formation of the excision complex is well documented, but the integration step has so far received less investigation. Like all mariner-like elements, Mos1 was thought to integrate into a TA dinucleotide without displaying any other target selection preferences. We set out to synthesize what is currently known about Mos1 insertion sites, and to define the characteristics of Mos1 insertion sequences in vitro and in vivo. Statistical analysis can be used to identify the TA dinucleotides that are non-randomly targeted for transposon integration. In vitro, no specific feature determining target choice other than the requirement for a TA dinucleotide has been identified. In vivo, data were obtained from two previously reported integration hotspots: the bacterial cat gene and the Caenorhabditis elegans rDNA locus. Analysis of these insertion sites revealed a preference for TA dinucleotides that are included in TATA or TA x TA motifs, or located within AT-rich regions. Analysis of the physical properties of sequences obtained in vitro and in vivo do not help to explain Mos1 integration preferences, suggesting that other characteristics must be involved in Mos1 target choice.
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Affiliation(s)
- Gwénaelle Crénès
- Université François Rabelais de Tours, GICC, Parc de Grandmont, 37200 Tours, France
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Kren BT, Unger GM, Sjeklocha L, Trossen AA, Korman V, Diethelm-Okita BM, Reding MT, Steer CJ. Nanocapsule-delivered Sleeping Beauty mediates therapeutic Factor VIII expression in liver sinusoidal endothelial cells of hemophilia A mice. J Clin Invest 2009; 119:2086-99. [PMID: 19509468 DOI: 10.1172/jci34332] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 04/22/2009] [Indexed: 12/16/2022] Open
Abstract
Liver sinusoidal endothelial cells are a major endogenous source of Factor VIII (FVIII), lack of which causes the human congenital bleeding disorder hemophilia A. Despite extensive efforts, gene therapy using viral vectors has shown little success in clinical hemophilia trials. Here we achieved cell type-specific gene targeting using hyaluronan- and asialoorosomucoid-coated nanocapsules, generated using dispersion atomization, to direct genes to liver sinusoidal endothelial cells and hepatocytes, respectively. To highlight the therapeutic potential of this approach, we encapsulated Sleeping Beauty transposon expressing the B domain-deleted canine FVIII in cis with Sleeping Beauty transposase in hyaluronan nanocapsules and injected them intravenously into hemophilia A mice. The treated mice exhibited activated partial thromboplastin times that were comparable to those of wild-type mice at 5 and 50 weeks and substantially shorter than those of untreated controls at the same time points. Further, plasma FVIII activity in the treated hemophilia A mice was nearly identical to that in wild-type mice through 50 weeks, while untreated hemophilia A mice exhibited no detectable FVIII activity. Thus, Sleeping Beauty transposon targeted to liver sinusoidal endothelial cells provided long-term expression of FVIII, without apparent antibody formation, and improved the phenotype of hemophilia A mice.
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Affiliation(s)
- Betsy T Kren
- Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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33
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Vink CA, Gaspar HB, Gabriel R, Schmidt M, McIvor RS, Thrasher AJ, Qasim W. Sleeping beauty transposition from nonintegrating lentivirus. Mol Ther 2009; 17:1197-204. [PMID: 19417741 DOI: 10.1038/mt.2009.94] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Lentiviral vectors enter cells with high efficiency and deliver stable transduction through integration into host chromosomes, but their preference for integration within actively transcribing genes means that insertional mutagenesis following disruption of host proto-oncogenes is a recognized concern. We have addressed this problem by combining the efficient cell and nuclear entry properties of HIV-1-derived lentiviral vectors with the integration profile benefits of Sleeping Beauty (SB) transposase. Importantly, this integration enzyme does not exhibit a preference for integration within active genes. We generated integrase-deficient lentiviral vectors (IDLVs) to carry SB transposon and transposase expression cassettes. IDLVs were able to deliver transient transposase expression to target cells, and episomal lentiviral DNA was found to be a suitable substrate for integration via the SB pathway. The hybrid vector system allows genomic integration of a minimal promoter-transgene cassette flanked by short SB inverted repeats (IRs) but devoid of HIV-1 long terminal repeats (LTRs) or other virus-derived sequences. Importantly, integration site analysis revealed redirection toward a profile mimicking SB-plasmid integration and away from integration within transcriptionally active genes favored by integrase-proficient lentiviral vectors (ILVs).
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Affiliation(s)
- Conrad A Vink
- Institute of Child Health, University College London, UK
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34
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Cancer gene discovery in mouse and man. Biochim Biophys Acta Rev Cancer 2009; 1796:140-61. [PMID: 19285540 PMCID: PMC2756404 DOI: 10.1016/j.bbcan.2009.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Revised: 03/03/2009] [Accepted: 03/05/2009] [Indexed: 12/31/2022]
Abstract
The elucidation of the human and mouse genome sequence and developments in high-throughput genome analysis, and in computational tools, have made it possible to profile entire cancer genomes. In parallel with these advances mouse models of cancer have evolved into a powerful tool for cancer gene discovery. Here we discuss the approaches that may be used for cancer gene identification in both human and mouse and discuss how a cross-species 'oncogenomics' approach to cancer gene discovery represents a powerful strategy for finding genes that drive tumourigenesis.
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35
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Muñoz-López M, Siddique A, Bischerour J, Lorite P, Chalmers R, Palomeque T. Transposition of Mboumar-9: identification of a new naturally active mariner-family transposon. J Mol Biol 2008; 382:567-72. [PMID: 18675277 PMCID: PMC2581405 DOI: 10.1016/j.jmb.2008.07.044] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 07/14/2008] [Accepted: 07/15/2008] [Indexed: 01/31/2023]
Abstract
Although mariner transposons are widespread in animal genomes, the vast majority harbor multiple inactivating mutations and only two naturally occurring elements are known to be active. Previously, we discovered a mariner-family transposon, Mboumar, in the satellite DNA of the ant Messor bouvieri. Several copies of the transposon contain a full-length open reading frame, including Mboumar-9, which has 64% nucleotide identity to Mos1 of Drosophila mauritiana. To determine whether Mboumar is currently active, we expressed and purified the Mboumar-9 transposase and demonstrate that it is able to catalyze the movement of a transposon from one plasmid to another in a genetic in vitro hop assay. The efficiency is comparable to that of the well-characterized mariner transposon Mos1. Transposon insertions were precise and were flanked by TA duplications, a hallmark of mariner transposition. Mboumar has been proposed to have a role in the evolution and maintenance of satellite DNA in M. bouvieri and its activity provides a means to examine the involvement of the transposon in the genome dynamics of this organism.
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Affiliation(s)
- Martín Muñoz-López
- Departamento de Biología Experimental, Area de Genética, Universidad de Jaén, 23071 Jaén, Spain
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36
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Cloning of glyceraldehyde-3-phosphate dehydrogenase from an Antarctic psychrophilic bacterium by inverse and splinkerette PCR. J Basic Microbiol 2008; 48:430-5. [DOI: 10.1002/jobm.200800008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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37
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Fujino K, Sekiguchi H. Site specific cytosine methylation in rice nonautonomous transposable element nDart. PLANT MOLECULAR BIOLOGY 2008; 67:511-8. [PMID: 18409027 DOI: 10.1007/s11103-008-9335-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 04/03/2008] [Indexed: 05/15/2023]
Abstract
The mobile nonautonomous element nDart, which is active in intact rice plants, exhibits locus specific transposition. Due to the high homogeneity of nDart elements, the locus specificity of nDart transposition might be controlled by factors other than genetic differences. In this study, we elucidated the regulation of the locus specificity of nDart transposition. The difference of transpositional activities in 10 nDart elements among rice varieties exhibiting nDart transposition was clearly correlated with the methylation state of nDart elements. Both hyper- and hypo-methylated nDart elements were inactive, while site specific methylation in both subterminal regions was identified in active nDart loci. The specific methylation sites contain the pentamer motif GCC/ACG. The repeated motifs in the subterminal region of nDart elements may contribute to the stable secondary structure of nDart elements with low free energy. Our results suggested that site specific cytosine methylation may loosen the stable secondary structure of the nDart element to allow it to bind TPase, which then perform the excision of nDart elements from genomic loci.
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Affiliation(s)
- Kenji Fujino
- Agricultural Research Institute, HOKUREN Federation of Agricultural Cooperatives, Higashi-5, Kita-15, Naganuma 0691317, Hokkaido, Japan.
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Abstract
Transposon systems are widely used for generating mutations in various model organisms. PiggyBac (PB) has recently been shown to transpose efficiently in the mouse germ line and other mammalian cell lines. To facilitate PB's application in mammalian genetics, we characterized the properties of the PB transposon in mouse embryonic stem (ES) cells. We first measured the transposition efficiencies of PB transposon in mouse embryonic stem cells. We next constructed a PB/SB hybrid transposon to compare PB and Sleeping Beauty (SB) transposon systems and demonstrated that PB transposition was inhibited by DNA methylation. The excision and reintegration rates of a single PB from two independent genomic loci were measured and its ability to mutate genes with gene trap cassettes was tested. We examined PB's integration site distribution in the mouse genome and found that PB transposition exhibited local hopping. The comprehensive information from this study should facilitate further exploration of the potential of PB and SB DNA transposons in mammalian genetics.
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39
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Transposon–Host Cell Interactions in the Regulation of Sleeping Beauty Transposition. TRANSPOSONS AND THE DYNAMIC GENOME 2008. [DOI: 10.1007/7050_2008_042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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40
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Takeda J, Keng VW, Horie K. Germline mutagenesis mediated by Sleeping Beauty transposon system in mice. Genome Biol 2007; 8 Suppl 1:S14. [PMID: 18047691 PMCID: PMC2106844 DOI: 10.1186/gb-2007-8-s1-s14] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice. Initially, the transposition efficiency was found to be low in cultured systems, but its activity in germ cells was unexpectedly high. This difference in transposition efficiency was found to be largely dependent on chromosomal status of the host genomic DNA and transposon vector design. The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice. Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.
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Affiliation(s)
- Junji Takeda
- Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan.
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41
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Wiznerowicz M, Jakobsson J, Szulc J, Liao S, Quazzola A, Beermann F, Aebischer P, Trono D. The Kruppel-associated box repressor domain can trigger de novo promoter methylation during mouse early embryogenesis. J Biol Chem 2007; 282:34535-41. [PMID: 17893143 DOI: 10.1074/jbc.m705898200] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The Krüppel-associated box (KRAB) domain is a transcriptional repression module responsible for the DNA binding-dependent gene silencing activity of hundreds of vertebrate zinc finger proteins. We previously exploited KRAB-mediated repression within the context of a tet repressor-KRAB fusion protein and of lentiviral vectors to create a method of external gene control. We demonstrated that with this system transcriptional silencing was fully reversible in cell culture as well as in vivo. Here we reveal that, in sharp contrast, KRAB-mediated repression results in irreversible gene silencing through promoter DNA methylation if it acts during the first few days of mouse development.
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Affiliation(s)
- Maciej Wiznerowicz
- School of Life Sciences, "Frontiers in Genetics" National Center for Competence in Research, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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