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Yoshiki A, Ballard G, Perez AV. Genetic quality: a complex issue for experimental study reproducibility. Transgenic Res 2022; 31:413-430. [PMID: 35751794 PMCID: PMC9489590 DOI: 10.1007/s11248-022-00314-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
Laboratory animal research involving mice, requires consideration of many factors to be controlled. Genetic quality is one factor that is often overlooked but is essential for the generation of reproducible experimental results. Whether experimental research involves inbred mice, spontaneous mutant, or genetically modified strains, exercising genetic quality through careful breeding, good recordkeeping, and prudent quality control steps such as validation of the presence of mutations and verification of the genetic background, will help ensure that experimental results are accurate and that reference controls are representative for the particular experiment. In this review paper, we will discuss various techniques used for the generation of genetically altered mice, and the different aspects to be considered regarding genetic quality, including inbred strains and substrains used, quality check controls during and after genetic manipulation and breeding. We also provide examples for when to use the different techniques and considerations on genetic quality checks. Further, we emphasize on the importance of establishing an in-house genetic quality program.
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Affiliation(s)
- Atsushi Yoshiki
- Experimental Animal Division, RIKEN BioResource Research Center, Tsukuba, 3050074, Japan.
| | - Gregory Ballard
- Comparative Medicine and Quality, The Jackson Laboratory, Bar Harbor, ME 04609, USA
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Human progranulin-expressing mice as a novel tool for the development of progranulin-modulating therapeutics. Neurobiol Dis 2021; 153:105314. [PMID: 33636385 DOI: 10.1016/j.nbd.2021.105314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 01/24/2021] [Accepted: 02/22/2021] [Indexed: 11/24/2022] Open
Abstract
The granulin protein (also known as, and hereafter referred to as, progranulin) is a secreted glycoprotein that contributes to overall brain health. Heterozygous loss-of-function mutations in the gene encoding the progranulin protein (Granulin Precursor, GRN) are a common cause of familial frontotemporal dementia (FTD). Gene therapy approaches that aim to increase progranulin expression from a single wild-type allele, an area of active investigation for the potential treatment of GRN-dependent FTD, will benefit from the availability of a mouse model that expresses a genomic copy of the human GRN gene. Here we report the development and characterization of a novel mouse model that expresses the entire human GRN gene in its native genomic context as a single copy inserted into a defined locus (Hprt) in the mouse genome. We show that human and mouse progranulin are expressed in a similar tissue-specific pattern, suggesting that the two genes are regulated by similar mechanisms. Human progranulin rescues a phenotype characteristic of progranulin-null mice, the exaggerated and early deposition of the aging pigment lipofuscin in the brain, indicating that the two proteins are functionally similar. Longitudinal behavioural and neuropathological analyses revealed no significant differences between wild-type and human progranulin-overexpressing mice up to 18 months of age, providing evidence that long-term increase of progranulin levels is well tolerated in mice. Finally, we demonstrate that human progranulin expression can be increased in the brain using an antisense oligonucleotide that inhibits a known GRN-regulating micro-RNA, demonstrating that the transgene is responsive to potential gene therapy drugs. Human progranulin-expressing mice represent a novel and valuable tool to expedite the development of progranulin-modulating therapeutics.
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Browning J, Rooney M, Hams E, Takahashi S, Mizuno S, Sugiyama F, Fallon PG, Kelly VP. Highly efficient CRISPR-targeting of the murine Hipp11 intergenic region supports inducible human transgene expression. Mol Biol Rep 2019; 47:1491-1498. [PMID: 31811500 DOI: 10.1007/s11033-019-05204-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 11/21/2019] [Indexed: 01/21/2023]
Abstract
Safe harbor loci allow predicable integration of a transgene into the genome without perturbing endogenous gene activity and for decades have been exploited in the mouse to investigate gene function, generate humanised models and create tissue specific reporter and Cre recombinase expressing lines. Herein, we show that the murine Hipp11 intergenic region can facilitate highly efficient integration of a large transgene-the human CD1A promoter and coding region-by means of CRISPR-Cas9 mediated homology directed repair. The data shows that the single copy human CD1A transgene is faithfully expressed in an inducible manner in homozygous animals in both macrophage and dendritic cells. Our results validate the Hipp11 intergenic region as being a highly amenable target site for functional transgene integration in mouse.
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Affiliation(s)
- Jill Browning
- School of Biochemistry& Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Michael Rooney
- School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Emily Hams
- School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Satoru Takahashi
- 1-1-1 Tennodai Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Seiya Mizuno
- 1-1-1 Tennodai Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Fumihiro Sugiyama
- 1-1-1 Tennodai Laboratory Animal Resource Center, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Padraic G Fallon
- School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Vincent P Kelly
- School of Biochemistry& Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
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Twenty-Seven Tamoxifen-Inducible iCre-Driver Mouse Strains for Eye and Brain, Including Seventeen Carrying a New Inducible-First Constitutive-Ready Allele. Genetics 2019; 211:1155-1177. [PMID: 30765420 PMCID: PMC6456315 DOI: 10.1534/genetics.119.301984] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/11/2019] [Indexed: 12/25/2022] Open
Abstract
To understand gene function, the cre/loxP conditional system is the most powerful available for temporal and spatial control of expression in mouse. However, the research community requires more cre recombinase expressing transgenic mouse strains (cre-drivers) that restrict expression to specific cell types. To address these problems, a high-throughput method for large-scale production that produces high-quality results is necessary. Further, endogenous promoters need to be chosen that drive cell type specific expression, or we need to further focus the expression by manipulating the promoter. Here we test the suitability of using knock-ins at the docking site 5′ of Hprt for rapid development of numerous cre-driver strains focused on expression in adulthood, using an improved cre tamoxifen inducible allele (icre/ERT2), and testing a novel inducible-first, constitutive-ready allele (icre/f3/ERT2/f3). In addition, we test two types of promoters either to capture an endogenous expression pattern (MaxiPromoters), or to restrict expression further using minimal promoter element(s) designed for expression in restricted cell types (MiniPromoters). We provide new cre-driver mouse strains with applicability for brain and eye research. In addition, we demonstrate the feasibility and applicability of using the locus 5′ of Hprt for the rapid generation of substantial numbers of cre-driver strains. We also provide a new inducible-first constitutive-ready allele to further speed cre-driver generation. Finally, all these strains are available to the research community through The Jackson Laboratory.
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Satoh D, Abe S, Kobayashi K, Nakajima Y, Oshimura M, Kazuki Y. Human and mouse artificial chromosome technologies for studies of pharmacokinetics and toxicokinetics. Drug Metab Pharmacokinet 2018; 33:17-30. [DOI: 10.1016/j.dmpk.2018.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/29/2017] [Accepted: 12/21/2017] [Indexed: 12/27/2022]
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Ohtsuka M, Miura H, Mochida K, Hirose M, Hasegawa A, Ogura A, Mizutani R, Kimura M, Isotani A, Ikawa M, Sato M, Gurumurthy CB. One-step generation of multiple transgenic mouse lines using an improved Pronuclear Injection-based Targeted Transgenesis (i-PITT). BMC Genomics 2015; 16:274. [PMID: 25887549 PMCID: PMC4404087 DOI: 10.1186/s12864-015-1432-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/04/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The pronuclear injection (PI) is the simplest and widely used method to generate transgenic (Tg) mice. Unfortunately, PI-based Tg mice show uncertain transgene expression due to random transgene insertion in the genome, usually with multiple copies. Thus, typically at least three or more Tg lines are produced by injecting over 200 zygotes and the best line/s among them are selected through laborious screening steps. Recently, we developed technologies using Cre-loxP system that allow targeted insertion of single-copy transgene into a predetermined locus through PI. We termed the method as PI-based Targeted Transgenesis (PITT). A similar method using PhiC31-attP/B system was reported subsequently. RESULTS Here, we developed an improved-PITT (i-PITT) method by combining Cre-loxP, PhiC31-attP/B and FLP-FRT systems directly under C57BL/6N inbred strain, unlike the mixed strain used in previous reports. The targeted Tg efficiency in the i-PITT typically ranged from 10 to 30%, with 47 and 62% in two of the sessions, which is by-far the best Tg rate reported. Furthermore, the system could generate multiple Tg mice simultaneously. We demonstrate that injection of up to three different Tg cassettes in a single injection session into as less as 181 zygotes resulted in production of all three separate Tg DNA containing targeted Tg mice. CONCLUSIONS The i-PITT system offers several advantages compared to previous methods: multiplexing capability (i-PITT is the only targeted-transgenic method that is proven to generate multiple different transgenic lines simultaneously), very high efficiency of targeted-transgenesis (up to 62%), significantly reduces animal numbers in mouse-transgenesis and the system is developed under C57BL/6N strain, the most commonly used pure genetic background. Further, the i-PITT system is freely accessible to scientific community.
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Affiliation(s)
- Masato Ohtsuka
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
| | - Hiromi Miura
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
| | - Keiji Mochida
- RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan.
| | - Michiko Hirose
- RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan.
| | - Ayumi Hasegawa
- RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan.
| | - Atsuo Ogura
- RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan. .,Graduate School of Life and Environmental Science, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki, 305-8572, Japan.
| | - Ryuta Mizutani
- Graduate School of Engineering, Tokai University, Kitakaname, Hiratsuka, Kanagawa, 259-1292, Japan.
| | - Minoru Kimura
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan.
| | - Ayako Isotani
- Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Masahiro Sato
- Section of Gene Expression Regulation, Frontier Science Research Center, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, Kagoshima, 890-8544, Japan.
| | - Channabasavaiah B Gurumurthy
- Mouse Genome Engineering Core Facility, Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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Sterneckert JL, Reinhardt P, Schöler HR. Investigating human disease using stem cell models. Nat Rev Genet 2014; 15:625-39. [PMID: 25069490 DOI: 10.1038/nrg3764] [Citation(s) in RCA: 194] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tractable and accurate disease models are essential for understanding disease pathogenesis and for developing new therapeutics. As stem cells are capable of self-renewal and differentiation, they are ideally suited both for generating these models and for obtaining the large quantities of cells required for drug development and transplantation therapies. Although proof of principle for the use of adult stem cells and embryonic stem cells in disease modelling has been established, induced pluripotent stem cells (iPSCs) have demonstrated the greatest utility for modelling human diseases. Furthermore, combining gene editing with iPSCs enables the generation of models of genetically complex disorders.
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Affiliation(s)
- Jared L Sterneckert
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Peter Reinhardt
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
| | - Hans R Schöler
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, 48149 Münster, Germany
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Iacovino M, Roth ME, Kyba M. Rapid genetic modification of mouse embryonic stem cells by Inducible Cassette Exchange recombination. Methods Mol Biol 2014; 1101:339-51. [PMID: 24233789 DOI: 10.1007/978-1-62703-721-1_16] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Embryonic stem cell (ESC) differentiation is a useful means by which to produce large quantities of cells in vitro representing early stages of embryonic development. A conditional gene expression system allows interrogation of factors at specific time points in the differentiation of ES cells to defined cell types. We have developed a method for rapidly generating conditional inducible murine ES cells by targeting genes into an Inducible Cassette Exchange (ICE) locus. The ICE locus encodes a doxycycline-inducible floxed Cre, which replaces itself with an incoming floxed gene of interest. The derivative cell lines, selected in G418, thus bear doxycycline-inducible transgenes. We provide detailed methods for performing ICE recombination and generating derivative doxycycline-inducible cell lines.
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Schmouth JF, Castellarin M, Laprise S, Banks KG, Bonaguro RJ, McInerny SC, Borretta L, Amirabbasi M, Korecki AJ, Portales-Casamar E, Wilson G, Dreolini L, Jones SJM, Wasserman WW, Goldowitz D, Holt RA, Simpson EM. Non-coding-regulatory regions of human brain genes delineated by bacterial artificial chromosome knock-in mice. BMC Biol 2013; 11:106. [PMID: 24124870 PMCID: PMC4015596 DOI: 10.1186/1741-7007-11-106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/30/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The next big challenge in human genetics is understanding the 98% of the genome that comprises non-coding DNA. Hidden in this DNA are sequences critical for gene regulation, and new experimental strategies are needed to understand the functional role of gene-regulation sequences in health and disease. In this study, we build upon our HuGX ('high-throughput human genes on the X chromosome') strategy to expand our understanding of human gene regulation in vivo. RESULTS In all, ten human genes known to express in therapeutically important brain regions were chosen for study. For eight of these genes, human bacterial artificial chromosome clones were identified, retrofitted with a reporter, knocked single-copy into the Hprt locus in mouse embryonic stem cells, and mouse strains derived. Five of these human genes expressed in mouse, and all expressed in the adult brain region for which they were chosen. This defined the boundaries of the genomic DNA sufficient for brain expression, and refined our knowledge regarding the complexity of gene regulation. We also characterized for the first time the expression of human MAOA and NR2F2, two genes for which the mouse homologs have been extensively studied in the central nervous system (CNS), and AMOTL1 and NOV, for which roles in CNS have been unclear. CONCLUSIONS We have demonstrated the use of the HuGX strategy to functionally delineate non-coding-regulatory regions of therapeutically important human brain genes. Our results also show that a careful investigation, using publicly available resources and bioinformatics, can lead to accurate predictions of gene expression.
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Affiliation(s)
- Jean-François Schmouth
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
- Genetics Graduate Program, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada
| | - Mauro Castellarin
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4S6, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Stéphanie Laprise
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Kathleen G Banks
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Russell J Bonaguro
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Simone C McInerny
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Lisa Borretta
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Mahsa Amirabbasi
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Andrea J Korecki
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Elodie Portales-Casamar
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Gary Wilson
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4S6, Canada
| | - Lisa Dreolini
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4S6, Canada
| | - Steven JM Jones
- Genetics Graduate Program, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4S6, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
- Genetics Graduate Program, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Daniel Goldowitz
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Robert A Holt
- Genetics Graduate Program, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada
- Canada’s Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 4S6, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2A1, Canada
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
- Genetics Graduate Program, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2A1, Canada
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Deussing JM. Targeted mutagenesis tools for modelling psychiatric disorders. Cell Tissue Res 2013; 354:9-25. [PMID: 24078022 DOI: 10.1007/s00441-013-1708-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/16/2013] [Indexed: 12/15/2022]
Abstract
In the 1980s, the basic principles of gene targeting were discovered and forged into sharp tools for efficient and precise engineering of the mouse genome. Since then, genetic mouse models have substantially contributed to our understanding of major neurobiological concepts and are of utmost importance for our comprehension of neuropsychiatric disorders. The "domestication" of site-specific recombinases and the continuous creative technological developments involving the implementation of previously identified biological principles such as transcriptional and posttranslational control now enable conditional mutagenesis with high spatial and temporal resolution. The initiation and successful accomplishment of large-scale efforts to annotate functionally the entire mouse genome and to build strategic resources for the research community have significantly accelerated the rapid proliferation and broad propagation of mouse genetic tools. Addressing neurobiological processes with the assistance of genetic mouse models is a routine procedure in psychiatric research and will be further extended in order to improve our understanding of disease mechanisms. In light of the highly complex nature of psychiatric disorders and the current lack of strong causal genetic variants, a major future challenge is to model of psychiatric disorders more appropriately. Humanized mice, and the recently developed toolbox of site-specific nucleases for more efficient and simplified tailoring of the genome, offer the perspective of significantly improved models. Ultimately, these tools will push the limits of gene targeting beyond the mouse to allow genome engineering in any model organism of interest.
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Affiliation(s)
- Jan M Deussing
- Max Planck Institute of Psychiatry, Molecular Neurogenetics, Kraepelinstrasse 2-10, 80804, Munich, Germany,
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A novel mammal-specific three partite enhancer element regulates node and notochord-specific Noto expression. PLoS One 2012; 7:e47785. [PMID: 23110100 PMCID: PMC3478275 DOI: 10.1371/journal.pone.0047785] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/17/2012] [Indexed: 11/19/2022] Open
Abstract
The vertebrate organizer and notochord have conserved, essential functions for embryonic development and patterning. The restricted expression of developmental regulators in these tissues is directed by specific cis-regulatory modules (CRMs) whose sequence conservation varies considerably. Some CRMs have been conserved throughout vertebrates and likely represent ancestral regulatory networks, while others have diverged beyond recognition but still function over a wide evolutionary range. Here we identify and characterize a mammalian-specific CRM required for node and notochord specific (NNC) expression of NOTO, a transcription factor essential for node morphogenesis, nodal cilia movement and establishment of laterality in mouse. A 523 bp enhancer region (NOCE) upstream the Noto promoter was necessary and sufficient for NNC expression from the endogenous Noto locus. Three subregions in NOCE together mediated full activity in vivo. Binding sites for known transcription factors in NOCE were functional in vitro but dispensable for NOCE activity in vivo. A FOXA2 site in combination with a novel motif was necessary for NOCE activity in vivo. Strikingly, syntenic regions in non-mammalian vertebrates showed no recognizable sequence similarities. In contrast to its activity in mouse NOCE did not drive NNC expression in transgenic fish. NOCE represents a novel, mammal-specific CRM required for the highly restricted Noto expression in the node and nascent notochord and thus regulates normal node development and function.
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Urban A, Rossier J. Genetic targeting of specific neuronal cell types in the cerebral cortex. PROGRESS IN BRAIN RESEARCH 2012; 196:163-92. [PMID: 22341326 DOI: 10.1016/b978-0-444-59426-6.00009-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Understanding the structure and function of cortical circuits requires the identification of and control over specific cell types in the cortex. To address these obstacles, recent optogenetic approaches have been developed. The capacity to activate, silence, or monitor specific cell types by combining genetics, virology, and optics will decipher the role of specific groups of neurons within circuits with a spatiotemporal resolution that overcomes standard approaches. In this review, the various strategies for selective genetic targeting of a defined neuronal population are discussed as well as the pros and cons of the use of transgenic animals and recombinant viral vectors for the expression of transgenes in a specific set of neurons.
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Affiliation(s)
- Alan Urban
- Laboratoire de Neurobiologie et Diversité Cellulaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7637, Ecole Supérieure de Physique et de Chimie Industrielles, Paris, France.
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13
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Schmouth JF, Bonaguro RJ, Corso-Diaz X, Simpson EM. Modelling human regulatory variation in mouse: finding the function in genome-wide association studies and whole-genome sequencing. PLoS Genet 2012; 8:e1002544. [PMID: 22396661 PMCID: PMC3291530 DOI: 10.1371/journal.pgen.1002544] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
An increasing body of literature from genome-wide association studies and human whole-genome sequencing highlights the identification of large numbers of candidate regulatory variants of potential therapeutic interest in numerous diseases. Our relatively poor understanding of the functions of non-coding genomic sequence, and the slow and laborious process of experimental validation of the functional significance of human regulatory variants, limits our ability to fully benefit from this information in our efforts to comprehend human disease. Humanized mouse models (HuMMs), in which human genes are introduced into the mouse, suggest an approach to this problem. In the past, HuMMs have been used successfully to study human disease variants; e.g., the complex genetic condition arising from Down syndrome, common monogenic disorders such as Huntington disease and β-thalassemia, and cancer susceptibility genes such as BRCA1. In this commentary, we highlight a novel method for high-throughput single-copy site-specific generation of HuMMs entitled High-throughput Human Genes on the X Chromosome (HuGX). This method can be applied to most human genes for which a bacterial artificial chromosome (BAC) construct can be derived and a mouse-null allele exists. This strategy comprises (1) the use of recombineering technology to create a human variant-harbouring BAC, (2) knock-in of this BAC into the mouse genome using Hprt docking technology, and (3) allele comparison by interspecies complementation. We demonstrate the throughput of the HuGX method by generating a series of seven different alleles for the human NR2E1 gene at Hprt. In future challenges, we consider the current limitations of experimental approaches and call for a concerted effort by the genetics community, for both human and mouse, to solve the challenge of the functional analysis of human regulatory variation.
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Affiliation(s)
- Jean-François Schmouth
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, Canada
- Genetics Graduate Program, University of British Columbia, Vancouver, Canada
| | - Russell J. Bonaguro
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, Canada
| | - Ximena Corso-Diaz
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, Canada
- Genetics Graduate Program, University of British Columbia, Vancouver, Canada
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, Canada
- Genetics Graduate Program, University of British Columbia, Vancouver, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
- * E-mail:
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Retina restored and brain abnormalities ameliorated by single-copy knock-in of human NR2E1 in null mice. Mol Cell Biol 2012; 32:1296-311. [PMID: 22290436 DOI: 10.1128/mcb.06016-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nr2e1 encodes a stem cell fate determinant of the mouse forebrain and retina. Abnormal regulation of this gene results in retinal, brain, and behavioral abnormalities in mice. However, little is known about the functionality of human NR2E1. We investigated this functionality using a novel knock-in humanized-mouse strain carrying a single-copy bacterial artificial chromosome (BAC). We also documented, for the first time, the expression pattern of the human BAC, using an NR2E1-lacZ reporter strain. Unexpectedly, cerebrum and olfactory bulb hypoplasia, hallmarks of the Nr2e1-null phenotype, were not fully corrected in animals harboring one functional copy of human NR2E1. These results correlated with an absence of NR2E1-lacZ reporter expression in the dorsal pallium of embryos and proliferative cells of adult brains. Surprisingly, retinal histology and electroretinograms demonstrated complete correction of the retina-null phenotype. These results correlated with appropriate expression of the NR2E1-lacZ reporter in developing and adult retina. We conclude that the human BAC contained all the elements allowing correction of the mouse-null phenotype in the retina, while missing key regulatory regions important for proper spatiotemporal brain expression. This is the first time a separation of regulatory mechanisms governing NR2E1 has been demonstrated. Furthermore, candidate genomic regions controlling expression in proliferating cells during neurogenesis were identified.
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15
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Iacovino M, Bosnakovski D, Fey H, Rux D, Bajwa G, Mahen E, Mitanoska A, Xu Z, Kyba M. Inducible cassette exchange: a rapid and efficient system enabling conditional gene expression in embryonic stem and primary cells. Stem Cells 2012; 29:1580-8. [PMID: 22039605 DOI: 10.1002/stem.715] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Genetic modification is critically enabling for studies addressing specification and maintenance of cell fate; however, methods for engineering modifications are inefficient. We demonstrate a rapid and efficient recombination system in which an inducible, floxed cre allele replaces itself with an incoming transgene. We target this inducible cassette exchange (ICE) allele to the (HPRT) locus and demonstrate recombination in murine embryonic stem cells (ESCs) and primary cells from derivative ICE mice. Using lentivectors, we demonstrate recombination at a randomly integrated ICE locus in human ESCs. To illustrate the utility of this system, we insert the myogenic regulator, Myf5, into the ICE locus in each platform. This enables efficient directed differentiation of mouse and human ESCs into skeletal muscle and conditional myogenic transdetermination of primary cells cultured in vitro. This versatile tool is thus well suited to gain-of-function studies probing gene function in the specification and reprogramming of cell fate.
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Affiliation(s)
- Michelina Iacovino
- Lillehei Heart Institute and Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
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16
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Devoy A, Bunton-Stasyshyn RKA, Tybulewicz VL, Smith AJ, Fisher EM. Genomically humanized mice: technologies and promises. Nat Rev Genet 2011; 13:14-20. [PMID: 22179716 PMCID: PMC4782217 DOI: 10.1038/nrg3116] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mouse models have become an invaluable tool for understanding human health and disease owing to our ability to manipulate the mouse genome exquisitely. Recent progress in genomic analysis has led to an increase in the number and type of disease-causing mutations detected and has also highlighted the importance of non-coding regions. As a result, there is increasing interest in creating 'genomically' humanized mouse models, in which entire human genomic loci are transferred into the mouse genome. The technical challenges towards achieving this aim are large but are starting to be tackled with success.
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Affiliation(s)
- Anny Devoy
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK , +44 203 456 7890
| | - Rosie KA Bunton-Stasyshyn
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK, , +44 203 456 7890
| | - Victor L.J. Tybulewicz
- MRC National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK, ; +44 20 8816 2184
| | - Andrew J.H. Smith
- Institute for Stem Cell Research, University of Edinburgh, Edinburgh EH9 3JQ, UK; and the MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, ; +44 131 651 7244
| | - Elizabeth M.C. Fisher
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK, ; +44 203 456 7890
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17
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BACs as tools for the study of genomic imprinting. J Biomed Biotechnol 2010; 2011:283013. [PMID: 21197393 PMCID: PMC3010669 DOI: 10.1155/2011/283013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/20/2010] [Accepted: 10/19/2010] [Indexed: 01/28/2023] Open
Abstract
Genomic imprinting in mammals results in the expression of genes from only one parental allele. Imprinting occurs as a consequence of epigenetic marks set down either in the father's or the mother's germ line and affects a very specific category of mammalian gene. A greater understanding of this distinctive phenomenon can be gained from studies using large genomic clones, called bacterial artificial chromosomes (BACs). Here, we review the important applications of BACs to imprinting research, covering physical mapping studies and the use of BACs as transgenes in mice to study gene expression patterns, to identify imprinting centres, and to isolate the consequences of altered gene dosage. We also highlight the significant and unique advantages that rapid BAC engineering brings to genomic imprinting research.
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18
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Young R, Wolf CR, Brown K, Hayes JD, Whitelaw CBA. Spatial monitoring of toxicity in HMOX-LacZ transgenic mice. Transgenic Res 2010; 19:897-902. [DOI: 10.1007/s11248-010-9363-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 01/04/2010] [Indexed: 11/27/2022]
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19
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Samuel MS, Munro J, Bryson S, Forrow S, Stevenson D, Olson MF. Tissue selective expression of conditionally-regulated ROCK by gene targeting to a defined locus. Genesis 2009; 47:440-6. [PMID: 19391117 DOI: 10.1002/dvg.20519] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
ROCK kinases regulate actin-myosin structures downstream of Rho GTPases. We generated mice expressing 4-hydroxytamoxifen (4HT)-regulated human ROCK II (ROCKII:mER) under the transcriptional control of the cytokeratin14 (K14) promoter. The K14-ROCKII:mER minigene was recombineered into a novel cloning vector containing the promoter and first exon of the human HPRT gene, and second and third exons of the mouse Hprt gene. Homologous recombination into the Hprt locus, which is deleted for the promoter and first two exons in HM1 embryonic stem cells, reconstitutes a functional Hprt gene, allowing for growth in HAT (hypoxanthine-aminopterin-thymidine) medium. K14-promoter-driven ROCKII:mER expression was restricted to a superficial cell layer in embryoid bodies, with increased ROCK substrate phosphorylation induced by 4HT. ROCKII:mER-expressing primary murine keratinocytes responded to 4HT with increased substrate phosphorylation and cytoskeleton rearrangements, indicating that ROCKII:mER activity is regulated by 4HT in the target tissue. K14-ROCKII:mER mice will be valuable for examining the role of ROCK in skin development and cancer.
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Affiliation(s)
- Michael S Samuel
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom
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20
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Abstract
Recombineering is an efficient method of in vivo genetic engineering applicable to chromosomal as well as episomal replicons in Escherichia coli. This method circumvents the need for most standard in vitro cloning techniques. Recombineering allows construction of DNA molecules with precise junctions without constraints being imposed by restriction enzyme site location. Bacteriophage homologous recombination proteins catalyze these recombineering reactions using double- and single-stranded linear DNA substrates, so-called targeting constructs, introduced by electroporation. Gene knockouts, deletions and point mutations are readily made, gene tags can be inserted and regions of bacterial artificial chromosomes or the E. coli genome can be subcloned by gene retrieval using recombineering. Most of these constructs can be made within about 1 week's time.
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21
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Next generation tools for high-throughput promoter and expression analysis employing single-copy knock-ins at the Hprt1 locus. Genomics 2008; 93:196-204. [PMID: 18950699 DOI: 10.1016/j.ygeno.2008.09.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 09/15/2008] [Accepted: 09/17/2008] [Indexed: 11/22/2022]
Abstract
We have engineered a set of useful tools that facilitate targeted single copy knock-in (KI) at the hypoxanthine guanine phosphoribosyl transferase 1 (Hprt1) locus. We employed fine scale mapping to delineate the precise breakpoint location at the Hprt1(b-m3) locus allowing allele specific PCR assays to be established. Our suite of tools contains four targeting expression vectors and a complementing series of embryonic stem cell lines. Two of these vectors encode enhanced green fluorescent protein (EGFP) driven by the human cytomegalovirus immediate-early enhancer/modified chicken beta-actin (CAG) promoter, whereas the other two permit flexible combinations of a chosen promoter combined with a reporter and/or gene of choice. We have validated our tools as part of the Pleiades Promoter Project (http://www.pleiades.org), with the generation of brain-specific EGFP positive germline mouse strains.
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Abstract
Drosophila melanogaster is a highly attractive model system for the study of numerous biological questions pertaining to development, genetics, cell biology, neuroscience and disease. Until recently, our ability to manipulate flies genetically relied heavily on the transposon-mediated integration of DNA into fly embryos. However, in recent years significant improvements have been made to the transgenic techniques available in this organism, particularly with respect to integrating DNA at specific sites in the genome. These new approaches will greatly facilitate the structure-function analyses of Drosophila genes, will enhance the ease and speed with which flies can be manipulated, and should advance our understanding of biological processes during normal development and disease.
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Affiliation(s)
- Koen J T Venken
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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23
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Mosaic complementation demonstrates a regulatory role for myosin VIIa in actin dynamics of stereocilia. Mol Cell Biol 2007; 28:1702-12. [PMID: 18160714 PMCID: PMC2258769 DOI: 10.1128/mcb.01282-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have developed a bacterial artificial chromosome transgenesis approach that allowed the expression of myosin VIIa from the mouse X chromosome. We demonstrated the complementation of the Myo7a null mutant phenotype producing a fine mosaic of two types of sensory hair cells within inner ear epithelia of hemizygous transgenic females due to X inactivation. Direct comparisons between neighboring auditory hair cells that were different only with respect to myosin VIIa expression revealed that mutant stereocilia are significantly longer than those of their complemented counterparts. Myosin VIIa-deficient hair cells showed an abnormally persistent tip localization of whirlin, a protein directly linked to elongation of stereocilia, in stereocilia. Furthermore, myosin VIIa localized at the tips of all abnormally short stereocilia of mice deficient for either myosin XVa or whirlin. Our results strongly suggest that myosin VIIa regulates the establishment of a setpoint for stereocilium heights, and this novel role may influence their normal staircase-like arrangement within a bundle.
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Shi J, Cai D, Chen X, Sheng H. Cloning of rabbit HPRT gene using the recombineering system. Acta Biochim Biophys Sin (Shanghai) 2007; 39:591-8. [PMID: 17687494 DOI: 10.1111/j.1745-7270.2007.00317.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hypoxanthine phosphoribosyltransferase (HPRT) plays an important role in the metabolic salvage of purines, and been used as an alternative pathway for mutant selection in many studies. To facilitate its application in rabbits, we have cloned the cDNA and genomic DNA of the rabbit HPRT gene using an approach that combines bioinformatics and recombineering methods. The cDNA is comprised of 1449 bp containing a coding sequence for a protein of 218 amino acids. The deduced amino acid sequence of the rabbit HPRT gene shares 98%, 97%, 98% and 94% identity with human, mouse, pig and cattle HPRT genes, respectively. Reverse transcription-polymerase chain reaction analysis showed that this gene is ubiquitously expressed in tissues of adult rabbit. The rabbit HPRT gene spans approximately 48 kb in length and consists of nine exons. The cloning of the rabbit HPRT gene shows the usefulness of the recombineering system in cloning genes of large size. This system may facilitate the subcloning of DNA from bacterial artificial chromosomes for cloning genes of large size or filling big gaps in genomic sequencing.
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Affiliation(s)
- Jianjun Shi
- Program for Graduation Studies, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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25
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Woll NL, Heaney JD, Bronson SK. Osteogenic nodule formation from single embryonic stem cell-derived progenitors. Stem Cells Dev 2007; 15:865-79. [PMID: 17253949 DOI: 10.1089/scd.2006.15.865] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The process of bone formation can be approximated in vitro in the form of a mineralized nodule. Osteoprogenitors and mesenchymal stem cells (MSCs), the immediate precursors of the osteoprogenitor, proliferate and differentiate into osteoblasts when placed into culture. These osteoblasts secrete and mineralize a matrix during a period of 3-4 weeks. The differentiation potential of embryonic stem (ES) cells suggests that ES cells should also have the ability to form osteogenic nodules in vitro. ES cells were allowed to form embryoid bodies (EBs) and were cultured in suspension for 2 days; EBs were disrupted and plated as single cells at concentrations as low as 25 cells/cm(2). We provide five lines of evidence for osteogenesis in these ES cell-derived cultures: (1) cell and colony morphology as revealed by phase-contrast microscopy, (2) mineralization of extracellular matrix as revealed by von Kossa staining, (3) quantitative real-time PCR (QRT-PCR) analysis of cDNA from entire plates and individual colonies revealing expression of genes characteristic of, and specific for, osteoblasts, (4) confocal microscopy of nodules from osteocalcin-green fluorescent protein (GFP) ES cell lines demonstrating the appropriate stage and position of osteoblasts expressing the reporter, and (5) immunostaining of nodules with a type I collagen antibody. Our method of initiating osteogenesis from ES cell-derived cultures is the only described method that allows for the observation and manipulation of the commitment stage of mesengenesis from single embryonic progenitors.
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Affiliation(s)
- Nicole L Woll
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033-0850, USA
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26
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Strathdee D, Ibbotson H, Grant SGN. Expression of transgenes targeted to the Gt(ROSA)26Sor locus is orientation dependent. PLoS One 2006; 1:e4. [PMID: 17183668 PMCID: PMC1762389 DOI: 10.1371/journal.pone.0000004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 08/31/2006] [Indexed: 01/18/2023] Open
Abstract
Background Targeting transgenes to a chosen location in the genome has a number of advantages. A single copy of the DNA construct can be inserted by targeting into regions of chromatin that allow the desired developmental and tissue-specific expression of the transgene. Methodology In order to develop a reliable system for reproducibly expressing trangenes it was decided to insert constructs at the Gt(ROSA)26Sor locus. A cytomegalovirus (CMV) promoter was used to drive expression of the Tetracycline (tet) transcriptional activator, rtTA2s-M2, and test the effectiveness of using the ROSA26 locus to allow transgene expression. The tet operator construct was inserted into one allele of ROSA26 and a tet responder construct controlling expression of EGFP was inserted into the other allele. Conclusions Expression of the targeted transgenes was shown to be affected by both the presence of selectable marker cassettes and by the orientation of the transgenes with respect to the endogenous ROSA26 promoter. These results suggest that transcriptional interference from the endogenous gene promoter or from promoters in the selectable marker cassettes may be affecting transgene expression at the locus. Additionally we have been able to determine the optimal orientation for transgene expression at the ROSA26 locus.
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Affiliation(s)
- Douglas Strathdee
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom; Centre for Neuroscience Research, University of Edinburgh, Edinburgh, Scotland.
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27
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Heaney JD, Bronson SK. Artificial chromosome-based transgenes in the study of genome function. Mamm Genome 2006; 17:791-807. [PMID: 16897340 DOI: 10.1007/s00335-006-0023-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Accepted: 04/06/2006] [Indexed: 12/01/2022]
Abstract
The transfer of large DNA fragments to the mouse genome in the form of bacterial, yeast or phage artificial chromosomes is an important process in the definition of transcription units, the modeling of inherited disease states, the dissection of candidate regions identified by linkage analysis and the construction of in vivo reporter genes. However, as with small recombinant transgenes, the transferred sequences are usually integrated randomly often with accompanying genomic alterations and variable expression of the introduced genes due to the site of integration and/or copy number. Therefore, alternative methods of integrating large genomic transgenes into the genome have been developed to avoid the variables associated with random integration. This review encourages the reader to imagine the large variety of applications where artificial chromosome transgenes can facilitate in vivo and ex vivo studies in the mouse and provides a context for making the necessary decisions regarding the specifics of experimental design.
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Affiliation(s)
- Jason D Heaney
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033-0850, USA
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