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Mopidevi B, Sivankutty I, Hao S, Ferreri NR, Kumar A. Effects of intron conversion in the human CYP11B2 gene on its transcription and blood pressure regulation in transgenic mice. J Biol Chem 2020; 295:11068-11081. [PMID: 32540969 DOI: 10.1074/jbc.ra120.013047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/13/2020] [Indexed: 01/19/2023] Open
Abstract
The human cytochrome P450 family 11 subfamily B member 2 (hCYP11B2) gene encodes aldosterone synthase, the rate-limiting enzyme in the biosynthesis of aldosterone. In some humans, hCYP11B2 undergoes a unique intron conversion whose function is largely unclear. The intron conversion is formed by a replacement of the segment of DNA within intron 2 of hCYP11B2 with the corresponding region of the hCYP11B1 gene. We show here that the intron conversion is located in an open chromatin form and binds more strongly to the transcriptional regulators histone acetyltransferase P300 (p300), NFκB, and CCAAT enhancer-binding protein α (CEBPα). Reporter constructs containing the intron conversion had increased promoter activity on transient transfection in H295R cells compared with WT intron 2. We generated humanized transgenic (TG) mice containing all the introns, exons, and 5'- and 3'-flanking regions of the hCYP11B2 gene containing either the intron conversion or WT intron 2. We found that TG mice containing the intron conversion have (a) increased plasma aldosterone levels, (b) increased hCYP11B2 mRNA and protein levels, and (c) increased blood pressure compared with TG mice containing WT intron 2. Results of a ChIP assay showed that chromatin obtained from the adrenals of TG mice containing the intron conversion binds more strongly to p300, NFκB, and CEBPα than to WT intron 2. These results uncover a functional role of intron conversion in hCYP11B2 and suggest a new paradigm in blood pressure regulation.
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Affiliation(s)
| | - Indu Sivankutty
- Department of Pathology, New York Medical College, Valhalla, New York, USA
| | - Shoujin Hao
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Nicholas R Ferreri
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Ashok Kumar
- Department of Pathology, New York Medical College, Valhalla, New York, USA
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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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Mopidevi B, Kaw MK, Puri N, Ponnala M, Jain S, Rana A, Keetha NR, Khuder SA, Fiering SN, Kumar A. Variable transcriptional regulation of the human aldosterone synthase gene causes salt-dependent high blood pressure in transgenic mice. ACTA ACUST UNITED AC 2014; 8:30-9. [PMID: 25504670 DOI: 10.1161/circgenetics.114.000694] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Aldosterone, synthesized in the adrenal cortex by the enzyme CYP11B2, induces positive sodium balance and predisposes to hypertension. Various investigators, using genomic DNA analyses, have linked -344T polymorphism in the human CYP11B2 (hCYP11B2) gene to human hypertension. hCYP11B2 gene promoter has 3 single-nucleotide polymorphisms in linkage disequilibrium: T/A at -663, T/C at -470, and C/T at -344. Variants ACT occur together and form the haplotype-I (Hap-I), whereas variants TTC constitute Hap-II. We hypothesize that these single-nucleotide polymorphisms, when present together, will lead to haplotype-dependent differences in the transcriptional regulation of the hCYP11B2 gene and affect blood pressure regulation. METHODS AND RESULTS We evaluated differences in tissue expression in vivo and consequential effects on blood pressure stemming from the 2 haplotypes. Novel transgenic mice with the hCYP11B2 gene, targeted to the mouse HPRT locus, with either Hap-II or Hap-I variant are used in this study. Our results show increased adrenal and renal expression of hCYP11B2 in transgenic mice with Hap-I when compared with mice with Hap-II. Importantly, we observed increased baseline blood pressure in Hap-I transgenic mice, an effect accentuated by a high-salt diet. Pathophysiological effects of elevated aldosterone were corroborated by our results showing upregulation of proinflammatory markers in renal tissues from the transgenic mice with Hap-I. CONCLUSIONS These findings characterize the haplotype-dependent regulation of the hCYP11B2 gene where -344T serves as a reporter polymorphism and show that Hap-I leads to increased expression of hCYP11B2, with permissive effects on blood pressure and inflammatory milieu.
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Affiliation(s)
- Brahmaraju Mopidevi
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Meenakshi K Kaw
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Nitin Puri
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Madhusudan Ponnala
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Sudhir Jain
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Anita Rana
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Narsimha R Keetha
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Sadik A Khuder
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Steven N Fiering
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.)
| | - Ashok Kumar
- From the Department of Physiology and Pharmacology (B.M., M.K.K., N.P., M.P., S.J., A.R., N.R.K., A.K.) and Department of Medicine (S.A.K.), College of Medicine, University of Toledo, OH; and Department of Microbiology and Immunology, Dartmouth Medical School, Lebanon, NH (S.N.F.).
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Dandapat A, Bosnakovski D, Hartweck LM, Arpke RW, Baltgalvis KA, Vang D, Baik J, Darabi R, Perlingeiro RCR, Hamra FK, Gupta K, Lowe DA, Kyba M. Dominant lethal pathologies in male mice engineered to contain an X-linked DUX4 transgene. Cell Rep 2014; 8:1484-96. [PMID: 25176645 PMCID: PMC4188423 DOI: 10.1016/j.celrep.2014.07.056] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/03/2014] [Accepted: 07/30/2014] [Indexed: 11/24/2022] Open
Abstract
Facioscapulohumeral muscular dystrophy (FSHD) is an enigmatic disease associated with epigenetic alterations in the subtelomeric heterochromatin of the D4Z4 macrosatellite repeat. Each repeat unit encodes DUX4, a gene that is normally silent in most tissues. Besides muscular loss, most patients suffer retinal vascular telangiectasias. To generate an animal model, we introduced a doxycycline-inducible transgene encoding DUX4 and 3' genomic DNA into a euchromatic region of the mouse X chromosome. Without induction, DUX4 RNA was expressed at low levels in many tissues and animals displayed a variety of unexpected dominant leaky phenotypes, including male-specific lethality. Remarkably, rare live-born males expressed DUX4 RNA in the retina and presented a retinal vascular telangiectasia. By using doxycycline to induce DUX4 expression in satellite cells, we observed impaired myogenesis in vitro and in vivo. This mouse model, which shows pathologies due to FSHD-related D4Z4 sequences, is likely to be useful for testing anti-DUX4 therapies in FSHD.
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Affiliation(s)
- Abhijit Dandapat
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA
| | - Darko Bosnakovski
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA
| | - Lynn M Hartweck
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA
| | - Robert W Arpke
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA
| | - Kristen A Baltgalvis
- Program in Physical Medicine and Rehabilitation, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Derek Vang
- Vascular Biology Center, Division of Hematology, Oncology, and Transplantation, Department of Medicine MMC 480, 420 Delaware Street SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - June Baik
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Medicine, University of Minnesota, 312 Church Street SE, Minneapolis, MN 55455, USA
| | - Radbod Darabi
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Medicine, University of Minnesota, 312 Church Street SE, Minneapolis, MN 55455, USA
| | - Rita C R Perlingeiro
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Medicine, University of Minnesota, 312 Church Street SE, Minneapolis, MN 55455, USA
| | - F Kent Hamra
- Department of Pharmacology, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Kalpna Gupta
- Vascular Biology Center, Division of Hematology, Oncology, and Transplantation, Department of Medicine MMC 480, 420 Delaware Street SE, University of Minnesota, Minneapolis, MN 55455, USA
| | - Dawn A Lowe
- Program in Physical Medicine and Rehabilitation, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Michael Kyba
- Lillehei Heart Institute, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, 2231 6th Street SE, Minneapolis, MN 55455, USA.
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Clarke SE, Kang JX, Ma DWL. The iFat1 transgene permits conditional endogenous n-3 PUFA enrichment both in vitro and in vivo. Transgenic Res 2014; 23:489-501. [PMID: 24622775 PMCID: PMC4010720 DOI: 10.1007/s11248-014-9788-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/03/2014] [Indexed: 01/22/2023]
Abstract
Fat-1 transgenic mice, which endogenously convert n-6 PUFA to n-3 PUFA, are a useful tool in health research; however with this model timing of n-3 PUFA enrichment cannot be directly controlled. To add such capability, the novel Cre-recombinase inducible fat-1 (iFat1) transgenic mouse has been developed. The aim of this study was to characterize the utility of the iFat1 transgene as a model of Cre-inducible endogenous n-3 PUFA enrichment. Functionality of the iFat1 transgene was screened both in vitro and in vivo. In the presence of Cre, the iFat1 transgene resulted in a balancing (p < 0.01) of the n-6/n-3 PUFA ratio within phospholipids in the human embryonic kidney 293T cell line. For in vivo analysis, iFat1 transgenic mice were crossed with the R26-Cre-ERT2 (Tam-Cre) mouse line, a tamoxifen inducible Cre-expression model. Tam-Cre/iFat1 double hybrids were transiently treated with tamoxifen at 6–7 weeks, then terminated 3 weeks later. Tamoxifen treated mice had increased (p < 0.05) tissue n-3 PUFA and ≥two-fold reduction (p < 0.05) in the n-6/n-3 PUFA ratio of liver, kidney and muscle phospholipids relative to vehicle treated controls. Collectively these findings suggest that the iFat1 transgenic mouse may be a promising tool to help elucidate the temporal effects through which n-3 PUFA impacts health related outcomes.
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Affiliation(s)
- Shannon E Clarke
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
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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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Yang C, McLeod AJ, Cotton AM, de Leeuw CN, Laprise S, Banks KG, Simpson EM, Brown CJ. Targeting of >1.5 Mb of human DNA into the mouse X chromosome reveals presence of cis-acting regulators of epigenetic silencing. Genetics 2012; 192:1281-93. [PMID: 23023002 PMCID: PMC3512139 DOI: 10.1534/genetics.112.143743] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/17/2012] [Indexed: 12/18/2022] Open
Abstract
Regulatory sequences can influence the expression of flanking genes over long distances, and X chromosome inactivation is a classic example of cis-acting epigenetic gene regulation. Knock-ins directed to the Mus musculus Hprt locus offer a unique opportunity to analyze the spread of silencing into different human DNA sequences in the identical genomic environment. X chromosome inactivation of four knock-in constructs, including bacterial artificial chromosome (BAC) integrations of over 195 kb, was demonstrated by both the lack of expression from the inactive X chromosome in females with nonrandom X chromosome inactivation and promoter DNA methylation of the human transgene in females. We further utilized promoter DNA methylation to assess the inactivation status of 74 human reporter constructs comprising >1.5 Mb of DNA. Of the 47 genes examined, only the PHB gene showed female DNA hypomethylation approaching the level seen in males, and escape from X chromosome inactivation was verified by demonstration of expression from the inactive X chromosome. Integration of PHB resulted in lower DNA methylation of the flanking HPRT promoter in females, suggesting the action of a dominant cis-acting escape element. Female-specific DNA hypermethylation of CpG islands not associated with promoters implies a widespread imposition of DNA methylation during X chromosome inactivation; yet transgenes demonstrated differential capacities to accumulate DNA methylation when integrated into the identical location on the inactive X chromosome, suggesting additional cis-acting sequence effects. As only one of the human transgenes analyzed escaped X chromosome inactivation, we conclude that elements permitting ongoing expression from the inactive X are rare in the human genome.
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Affiliation(s)
- Christine Yang
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Andrea J. McLeod
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Allison M. Cotton
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Charles N. de Leeuw
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Stéphanie Laprise
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Kathleen G. Banks
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
- Department of Medical Genetics, Department of Psychiatry, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada
| | - Carolyn J. Brown
- Department of Medical Genetics, Molecular Epigenetics Group, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
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Schachtner H, Li A, Stevenson D, Calaminus SDJ, Thomas S, Watson SP, Sixt M, Wedlich-Soldner R, Strathdee D, Machesky LM. Tissue inducible Lifeact expression allows visualization of actin dynamics in vivo and ex vivo. Eur J Cell Biol 2012; 91:923-929. [PMID: 22658956 PMCID: PMC3930012 DOI: 10.1016/j.ejcb.2012.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/01/2012] [Accepted: 04/12/2012] [Indexed: 11/21/2022] Open
Abstract
We describe here the development and characterization of a conditionally inducible mouse model expressing Lifeact-GFP, a peptide that reports the dynamics of filamentous actin. We have used this model to study platelets, megakaryocytes and melanoblasts and we provide evidence that Lifeact-GFP is a useful reporter in these cell types ex vivo. In the case of platelets and megakaryocytes, these cells are not transfectable by traditional methods, so conditional activation of Lifeact allows the study of actin dynamics in these cells live. We studied melanoblasts in native skin explants from embryos, allowing the visualization of live actin dynamics during cytokinesis and migration. Our study revealed that melanoblasts lacking the small GTPase Rac1 show a delay in the formation of new pseudopodia following cytokinesis that accounts for the previously reported cytokinesis delay in these cells. Thus, through use of this mouse model, we were able to gain insights into the actin dynamics of cells that could only previously be studied using fixed specimens or following isolation from their native tissue environment.
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Affiliation(s)
- Hannah Schachtner
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD
| | - Ang Li
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD
| | - David Stevenson
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD
| | - Simon D. J. Calaminus
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD
| | - Steve Thomas
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT
| | - Steve P. Watson
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT
| | - Michael Sixt
- Institute of Science and Technology, Am Campus 1, A-3400 Klosterneuberg, Austria
| | - Roland Wedlich-Soldner
- Cellular Dynamics and Cell Patterning, Max-Planck Institute of Biochemistry, Am, Klopferspitz 18, 82152 Martinsried, Germany
| | - Douglas Strathdee
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD
| | - Laura M. Machesky
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD
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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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Platt B, Drever B, Koss D, Stoppelkamp S, Jyoti A, Plano A, Utan A, Merrick G, Ryan D, Melis V, Wan H, Mingarelli M, Porcu E, Scrocchi L, Welch A, Riedel G. Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1. PLoS One 2011; 6:e27068. [PMID: 22096518 PMCID: PMC3214038 DOI: 10.1371/journal.pone.0027068] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 10/09/2011] [Indexed: 11/18/2022] Open
Abstract
Late-stage neuropathological hallmarks of Alzheimer's disease (AD) are β-amyloid (βA) and hyperphosphorylated tau peptides, aggregated into plaques and tangles, respectively. Corresponding phenotypes have been mimicked in existing transgenic mice, however, the translational value of aggressive over-expression has recently been questioned. As controlled gene expression may offer animal models with better predictive validity, we set out to design a transgenic mouse model that circumvents complications arising from pronuclear injection and massive over-expression, by targeted insertion of human mutated amyloid and tau transgenes, under the forebrain- and neurone-specific CaMKIIα promoter, termed PLB1Double. Crossing with an existing presenilin 1 line resulted in PLB1Triple mice. PLB1Triple mice presented with stable gene expression and age-related pathology of intra-neuronal amyloid and hyperphosphorylated tau in hippocampus and cortex from 6 months onwards. At this early stage, pre-clinical 18FDG PET/CT imaging revealed cortical hypometabolism with increased metabolic activity in basal forebrain and ventral midbrain. Quantitative EEG analyses yielded heightened delta power during wakefulness and REM sleep, and time in wakefulness was already reliably enhanced at 6 months of age. These anomalies were paralleled by impairments in long-term and short-term hippocampal plasticity and preceded cognitive deficits in recognition memory, spatial learning, and sleep fragmentation all emerging at ∼12 months. These data suggest that prodromal AD phenotypes can be successfully modelled in transgenic mice devoid of fibrillary plaque or tangle development. PLB1Triple mice progress from a mild (MCI-like) state to a more comprehensive AD-relevant phenotype, which are accessible using translational tools such as wireless EEG and microPET/CT.
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Affiliation(s)
- Bettina Platt
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Aberdeen, United Kingdom.
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11
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Pickell L, Wu Q, Wang XL, Leclerc D, Friedman H, Peterson AC, Rozen R. Targeted insertion of two Mthfr promoters in mice reveals temporal- and tissue-specific regulation. Mamm Genome 2011; 22:635-47. [PMID: 21769670 DOI: 10.1007/s00335-011-9351-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 06/07/2011] [Indexed: 11/30/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, synthesizes 5-methyltetrahydrofolate, the main circulatory form of folate which is required for maintaining nontoxic levels of homocysteine and providing one-carbon units for methylation. A common 677C → T variant in MTHFR confers mild MTHFR deficiency and has been associated with a number of human disorders, including neural tube defects and vascular disease. Two promoters of Mthfr, designated as upstream and downstream promoters, are located upstream of a transcription start site cluster and have previously demonstrated cell-specific activities. In this study we used a unique approach for targeted, single-copy transgene insertion to generate transgenic mice carrying a Mthfr upstream or Mthfr downstream promoter-reporter construct located 5' to the endogenous Hprt (hypoxanthine-guanine phosphoribosyltransferase) locus. The Mthfr downstream promoter demonstrated activity in the neural tube, neural crest cells, dorsal root ganglia, heart, and endothelial cells of blood vessels in 10.5-days post coitum embryos and placentas. Upstream promoter activity was absent at this developmental stage. Postnatally, both promoters demonstrated activity in the brain stem, hippocampus, and thalamus of 1-week-old brain that became stronger in the adult. The Mthfr upstream promoter also showed activity in the cerebellum and cerebral cortex. Both promoters were active in male reproductive tissues, including 1-week-old epididymides, and there was upstream promoter-specific activity in the adult testis. Our investigation of Mthfr regulation in an in vivo mouse model revealed temporal- and tissue-specific regulation that supports important roles for MTHFR in the developing embryo, and in postnatal brain and male reproductive tissues.
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Affiliation(s)
- Laura Pickell
- Departments of Human Genetics and Pediatrics, McGill University and Montreal Children's Hospital Research Institute, Montreal, QC, Canada
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12
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Dela Cruz CS, Kang MJ, Cho WK, Lee CG. Transgenic modelling of cytokine polarization in the lung. Immunology 2010; 132:9-17. [PMID: 21091906 DOI: 10.1111/j.1365-2567.2010.03376.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The lung is one of the commonest sites of exposure to environmental allergen or pathogen, so the expression of a variety of cytokines in the lung is dynamically regulated by inflammatory or structural cells in the lung. In the last decades, characterization of the local lung cytokine milieu in allergic or injury models has identified a collective role of certain cytokines, such as type 1 or type 2 cytokines, driving polarized inflammatory and tissue phenotypes. With the development of transgenic mouse modelling systems, the effector function of individual cytokine and the pathophysiological consequences of cytokine polarization in the lung have been effectively evaluated. Here, we present an overview of the transgenic systems currently used to assess the biological function of cytokine or other mediators in the lung. We discuss the inflammatory and tissue phenotypes detected in the lungs of transgenic mice over-expressing representative T helper type 1 (interferon-γ, interleukin-12), T helper type 2 (interleukins -4, -5, -9, -10 and -13), and T helper type 17 cytokines. The effects of genetic modification of cytokine receptors or transcriptional factors such as GATA-3 and T-bet in pulmonary inflammation and remodelling tissue responses are also discussed because these transcription factors are regarded as essential regulators of cytokine polarization. Finally, we discuss the limitations and future application of transgenic approaches in the studies of human lung diseases characterized by cytokine polarization.
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Affiliation(s)
- Charles S Dela Cruz
- Section of Pulmonary and Critical Care Medicine, Yale University School of Medicine, Department of Internal Medicine, New Haven, CT 06520, USA
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Grobe JL, Dickson ME, Park S, Davis DR, Born EJ, Sigmund CD. Cardiovascular consequences of genetic variation at -6/235 in human angiotensinogen using "humanized" gene-targeted mice. Hypertension 2010; 56:981-7. [PMID: 20823378 DOI: 10.1161/hypertensionaha.110.157354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Genetic and functional data support a role for angiotensinogen in blood pressure control, and many population studies have suggested that polymorphisms in the angiotensinogen gene contribute to hypertension. Two common haplotypes of the human angiotensinogen gene are -6A/235T and -6G/235M. To study their contributions to blood pressure regulation in a controlled model system, we developed triple-transgenic mice expressing either -6A/235T or -6G/235M human angiotensinogen, expressing either an overexpressed and poorly regulated (REN9) or a tightly regulated (PAC160) human renin, and all carrying a null mutation in the endogenous murine angiotensinogen gene. These humanized mice were then examined for blood pressure differences at baseline and after a high-salt diet, changes in cardiovascular organ weight, and differences in angiotensinogen and renin gene expression. Mice expressing the -6G/235M haplotype on the PAC160 background exhibited increased blood pressure and cardiac hypertrophy at baseline. In contrast, all of the mice with the REN9 background had equivalent baseline blood pressures. On the REN9 background, there was a greater increase in blood pressure in -6A/235T in response to a high-salt diet, providing evidence it may be a susceptibility allele. There were no differences in angiotensinogen expression between haplotypes on either background strain. The data suggest that the impact of angiotensinogen haplotypes on cardiovascular end points may be dependent on renin status and environmental influences, such as dietary sodium. These insights may help explain the discrepancies among observational studies that have examined roles for the -6A/235T and -6G/235M angiotensinogen haplotypes in varied human populations.
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Affiliation(s)
- Justin L Grobe
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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14
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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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15
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Coon CI, Fiering S, Gaudet J, Wyatt CA, Brinckerhoff CE. Site controlled transgenic mice validating increased expression from human matrix metalloproteinase (MMP-1) promoter due to a naturally occurring SNP. Matrix Biol 2009; 28:425-31. [PMID: 19577645 PMCID: PMC2783711 DOI: 10.1016/j.matbio.2009.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 06/04/2009] [Accepted: 06/23/2009] [Indexed: 12/15/2022]
Abstract
Matrix metalloproteinases (MMPs) comprise a family of more than 20 members, each with the ability to degrade components of the extracellular matrix. The interstitial collagenases have the unique capacity to degrade the stromal collagens, types I, II and III, the body's most abundant proteins. These collagenases include MMP-1, MMP-8, MMP-13 and MMP-14. MMP-1, with a very broad expression pattern, has major roles in mediating matrix destruction in many diseases. We have described a single nucleotide polymorphism (SNP) in the MMP-1 promoter that augments transcription. This SNP is the presence or absence of an extra guanine (G) at -1607 bp, which creates the sequence 5'-GGAA-3'(2G allele), and which is an ETS binding site. Compared to the 1G allele (5'-GAA-3'), the 2G SNP is associated with enhanced transcription of MMP-1 and increased enzymatic activity. Although murine systems are often used to model human diseases, mice have only distant homologues of human MMP-1. Therefore, we used a technique for the targeted insertion of a single copy of a gene at the HPRT locus to compare expression of the 1G and 2G alleles. We generated transgenic mice with -4372 bp of the human MMP-1 promoter containing either the 1G or 2G SNP in front of the lac Z (E.coli ss-galactosidase) gene. We measured the relative expression of the transgenes in vitro in embryonic stem (ES) cells and in fibroblasts derived from embryonic mice. Our data show modest constitutive expression of ss-galactosidase mRNA and protein from these alleles, with the 2G allele more transcriptionally active than the 1G allele. We conclude that these mice represent a model for integration of a single copy of the human MMP-1 promoter into the murine genome, and could be used to study MMP-1 gene expression in a murine system.
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Affiliation(s)
- Charles I. Coon
- Department of Medicine Dartmouth Medical School, Dartmouth Hitchcock Medical CenterLebanon, NH 03756
| | - Steven Fiering
- Department of Microbiology and Immunology Dartmouth Medical School, Dartmouth Hitchcock Medical Center Lebanon, NH 03756
| | - Justin Gaudet
- Department of Biochemistry Dartmouth Medical School, Dartmouth Hitchcock Medical CenterLebanon, NH 03756
| | - Colby A. Wyatt
- Department of Biochemistry Dartmouth Medical School, Dartmouth Hitchcock Medical CenterLebanon, NH 03756
| | - Constance E. Brinckerhoff
- Department of Medicine Dartmouth Medical School, Dartmouth Hitchcock Medical CenterLebanon, NH 03756
- Department of Biochemistry Dartmouth Medical School, Dartmouth Hitchcock Medical CenterLebanon, NH 03756
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16
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Palais G, Nguyen Dinh Cat A, Friedman H, Panek-Huet N, Millet A, Tronche F, Gellen B, Mercadier JJ, Peterson A, Jaisser F. Targeted transgenesis at the HPRT locus: an efficient strategy to achieve tightly controlled in vivo conditional expression with the tet system. Physiol Genomics 2009; 37:140-6. [DOI: 10.1152/physiolgenomics.90328.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The tet-inducible system has been widely used to achieve conditional gene expression in genetically modified mice. To alleviate the frequent difficulties associated with recovery of relevant transgenic founders, we tested whether a controlled strategy of transgenesis would support reliable cell-specific, doxycycline (Dox)-controlled transgene expression in vivo. Taking advantage of the potent hypoxanthine-aminopterin-thymidine selection strategy and an embryonic stem (ES) cell line supporting efficient germ-line transmission, we used hypoxanthine phosphoribosyltransferase ( HPRT) targeting to insert a single copy tet-inducible construct designed to allow both glucocorticoid receptor (GR) and β-galactosidase (β-Gal) expression. Conditional, Dox-dependent GR and β-Gal expression was evidenced in targeted ES cells. Breeding ES-derived single copy transgenic mice with mice bearing appropriate tet transactivators resulted in β-Gal expression both qualitatively and quantitatively similar to that observed in mice with random integration of the same construct. Interestingly, GR expression in mice was dependent on transgene orientation in the HPRT locus while embryonic stem cell expression was not. Thus, a conditional construct inserted in single copy and in predetermined orientation at the HPRT locus demonstrated a Dox-dependent gene expression phenotype in adult mice suggesting that controlled insertion of tet-inducible constructs at the HPRT locus can provide an efficient alternative strategy to reproducibly generate animal models with tetracycline-induced transgene expression.
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Affiliation(s)
- G. Palais
- Institut National de la Santé et de la Recherche Médicale (INSERM), U772
- Collège de France
- l'Université Paris Descartes, Paris, France
| | - A. Nguyen Dinh Cat
- Institut National de la Santé et de la Recherche Médicale (INSERM), U772
- Collège de France
- l'Université Paris Descartes, Paris, France
| | - H. Friedman
- Laboratory of Developmental Biology, H-5, Royal Victoria Hospital, McGill University Health Centre, Montreal, Quebec, Canada
| | - N. Panek-Huet
- Institut National de la Santé et de la Recherche Médicale (INSERM), U772
- Collège de France
- l'Université Paris Descartes, Paris, France
| | - A. Millet
- Collège de France
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 7148
| | - F. Tronche
- Collège de France
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 7148
| | - B. Gellen
- INSERM, U698
- l'Université Paris 7, Paris, France
| | | | - A. Peterson
- Laboratory of Developmental Biology, H-5, Royal Victoria Hospital, McGill University Health Centre, Montreal, Quebec, Canada
| | - F. Jaisser
- Institut National de la Santé et de la Recherche Médicale (INSERM), U772
- Collège de France
- l'Université Paris Descartes, Paris, France
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17
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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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18
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Sigmund CD. A growing chain of evidence linking genetic variation in angiotensinogen with essential hypertension: focus on “A haplotype of human angiotensinogen gene containing −217A increases blood pressure in transgenic mice compared with −217G,” by Jain et al. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1846-8. [DOI: 10.1152/ajpregu.90856.2008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jain S, Vinukonda G, Fiering SN, Kumar A. A haplotype of human angiotensinogen gene containing -217A increases blood pressure in transgenic mice compared with -217G. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1849-57. [PMID: 18945948 DOI: 10.1152/ajpregu.90637.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The human angiotensinogen (hAGT) gene contains an A/G polymorphism at -217, and frequency of -217A allele is increased in African-American hypertensive patients. The hAGT gene has seven polymorphic sites in the 1.2-kb region of its promoter, and variant -217A almost always occurs with -532T, -793A, and -1074T, whereas variant -217G almost always occurs with -532C, -793G, and -1074G. Since allele -6A is the predominant allele in African-Americans, the AGT gene can be subdivided into two main haplotypes, -6A:-217A (AA) and -6A:-217G (AG). To understand the role of these haplotypes on hAGT gene expression and on blood pressure regulation in an in vivo situation, we have generated double transgenic mice containing human renin gene and either AA or AG haplotype of the hAGT gene using knock-in strategy at the hypoxanthine phosphoribosyltransferase locus. We show here that 1) hAGT mRNA level is increased in the liver by 60% and in the kidney by 40%; and 2) plasma AGT level is increased by approximately 40%, and plasma angiotensin II level is increased by approximately 50% in male double transgenic mice containing AA haplotype of the hAGT gene compared with the AG haplotype. In addition, systolic blood pressure is increased by 8 mmHg in transgenic mice containing the AA haplotype compared with the AG haplotype. This is the first report to show the effect of polymorphisms in the promoter of a human gene on its transcription in an in vivo situation that ultimately leads to an increase in blood pressure.
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Affiliation(s)
- Sudhir Jain
- Department of Pathology, New York Medical College, Rm 455, Basic Science Bldg., Valhalla, NY 10595, USA
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20
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Yurchenko E, Friedman H, Hay V, Peterson A, Piccirillo CA. Ubiquitous expression of mRFP-1 in vivo by site-directed transgenesis. Transgenic Res 2007; 16:29-40. [PMID: 17077985 DOI: 10.1007/s11248-006-9030-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 07/27/2006] [Indexed: 10/24/2022]
Abstract
Progress in our understanding of the molecular cellular basis of immune function depends on our ability to track and image individual immune cells in vivo. To this end, the development of mouse models over-expressing various fluorescent proteins would represent an important experimental tool. In this report, we describe the generation and characterization of pUbi-mRFP-1 transgenic mice, in which the monomeric form of red fluorescent protein is ubiquitously expressed in various lymphoid and non-lymphoid tissues. Our newly generated pUbi-mRFP-1 mice are unique among previously reported mice transgenic for red fluorescent proteins because a single-copy of the mRFP-1 transgene driven by human ubiquitin C promoter has been integrated by homologous recombination into the mouse hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus. We show that the distinct and uniform levels of mRFP-1 expression allow easy identification of transferred hematopoietic cells by FACS analysis or confocal microscopy, even when the transferred population represents a very small proportion in the target organ. Also, even in long-term experiments, we have seen no evidence of rejection of transferred pUbi-mRFP-1 lymphocytes. Due to its far-red spectrum, mRFP-1 is an ideal partner for dual imaging with green fluorescent proteins. We observed a good visual separation between donor lymphocytes derived from either mRFP-1 or eGFP transgenic mice in recipient animals. Our study suggests that the new pUbi-mRFP-1 transgenic mouse strain offers new opportunities for studying cellular interactions and migratory patterns of cells, especially for dual imaging of different cell types. In summary, our results demonstrate that a controlled strategy of transgenesis provides an effective means of ubiquitously expressing fluorescent proteins in vivo.
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Affiliation(s)
- Ekaterina Yurchenko
- Department of Microbiology and Immunology, McGill University, Montreal, H3A 2B4, Canada
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21
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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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Touw K, Hoggatt AM, Simon G, Herring BP. Hprt-targeted transgenes provide new insights into smooth muscle-restricted promoter activity. Am J Physiol Cell Physiol 2006; 292:C1024-32. [PMID: 17079332 DOI: 10.1152/ajpcell.00445.2006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mouse telokin and SM22alpha promoters have previously been shown to direct smooth muscle cell-specific expression of transgenes in vivo in adult mice. However, the activity of these promoters is highly dependent on the integration site of the transgene. In the current study, we found that the ectopic expression of telokin promoter transgenes could be abolished by flanking the transgene with insulator elements from the H19 gene. However, the insulator elements did not increase the proportion of mouse lines that exhibited consistent, detectable levels of transgene expression. In contrast, when transgenes were targeted to the hprt locus, both telokin and SM22alpha promoters resulted in reproducible patterns and levels of transgene expression in all lines of mice examined. Telokin promoter transgene expression was restricted to smooth muscle tissues in adult and embryonic mice. As reported previously, SM22alpha transgenes were expressed at high levels specifically in arterial smooth muscle cells; however, in contrast to randomly integrated transgenes, the hprt-targeted SM22alpha transgenes were also expressed at high levels in smooth muscle cells in veins, bladder, and gallbladder. Using hprt-targeted transgenes, we further analyzed elements within the telokin promoter required for tissue specific activity in vivo. Analysis of these transgenes revealed that the CArG element in the telokin promoter is required for promoter activity in all tissues and that the CArG element and adjacent AT-rich region are sufficient to drive transgene expression in bladder but not intestinal smooth muscle cells.
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Affiliation(s)
- Ketrija Touw
- Dept. of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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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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Sherrod M, Davis DR, Zhou X, Cassell MD, Sigmund CD. Glial-specific ablation of angiotensinogen lowers arterial pressure in renin and angiotensinogen transgenic mice. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1763-9. [PMID: 16109805 DOI: 10.1152/ajpregu.00435.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiotensinogen (AGT) is mainly expressed in glial cells in close proximity to renin-expressing neurons in the brain. We previously reported that glial-specific overexpression of ANG II results in mild hypertension. Here, we tested the hypothesis that glial-derived AGT plays an important role in blood pressure regulation in hypertensive mice carrying human renin (hREN) and human AGT transgenes under the control of their own endogenous promoters. To perform a glial-specific deletion of AGT, we used an AGT transgene containing loxP sites (hAGT(flox)), so the gene can be permanently ablated in the presence of cre-recombinase expression, driven by the glial fibrillary acidic protein (GFAP) promoter. Triple transgenic mice (RAC) containing a: 1) systemically expressed hREN transgene, 2) systemically expressed hAGT(flox) transgene, and 3) GFAP-cre-recombinase were generated and compared with double transgenic mice (RA) lacking cre-recombinase. Liver and kidney hAGT mRNA levels were unaltered in RAC and RA mice, as was the level of hAGT in the systemic circulation, consistent with the absence of cre-recombinase expression in those tissues. Whereas hAGT mRNA was present in the brain of RA mice (lacking cre-recombinase), it was absent from the brain of RAC mice expressing cre-recombinase, confirming brain-specific elimination of AGT. Immunohistochemistry revealed a loss of AGT immunostaining glial cells throughout the brain in RAC mice. Arterial pressure measured by radiotelemetry was significantly lower in RAC than RA mice and unchanged from nontransgenic control mice. These data suggest that there is a major contribution of glial-AGT to the hypertensive state in mice carrying systemically expressed hREN and hAGT genes and confirm the importance of a glial source of ANG II substrate in the brain.
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Affiliation(s)
- Mikhiela Sherrod
- Genetics Graduate Program, Roy J. and Lucille A. Carver College of Medicine, Univ. of Iowa, Iowa City, Iowa 52242, USA
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Heaney JD, Rettew AN, Bronson SK. Tissue-specific expression of a BAC transgene targeted to the Hprt locus in mouse embryonic stem cells. Genomics 2005; 83:1072-82. [PMID: 15177560 DOI: 10.1016/j.ygeno.2003.12.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Accepted: 12/31/2003] [Indexed: 10/26/2022]
Abstract
The hypoxanthine phosphoribosyltransferase (Hprt) locus has been shown to have minimal influence on transgene expression when used as a surrogate site in the mouse genome. We have developed a method to transfer bacterial artificial chromosomes (BACs) as a single copy into the partially deleted Hprt locus of embryonic stem cells. BACs were modified by Cre/loxP recombination to contain the sequences necessary for homologous recombination into and complementation of the partially deleted Hprt locus. Modified BACs were shown to undergo homologous recombination into the genome intact, to be stably transmitted through the germ line of transgenic mice, and to be expressed in the proper tissue-specific manner. This technology will facilitate many studies in which correct interpretation of data depends on developmentally appropriate transgene expression in the absence of rearrangements or deletions of endogenous DNA.
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Affiliation(s)
- Jason D Heaney
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine H166, 500 University Drive, Hershey, PA 17033-0850, USA
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Habets PEMH, Clout DEW, Lekanne Deprez RH, van Roon MA, Moorman AFM, Christoffels VM. Cardiac expression of Gal4 causes cardiomyopathy in a dose-dependent manner. J Muscle Res Cell Motil 2004; 24:205-9. [PMID: 14609031 DOI: 10.1023/a:1026055612227] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cardiac expression of a transgene is a common approach for determining the role of gene products in the processes underlying cardiomyopathy and heart failure (HF). We have generated transgenic mice that express the 'harmless' yeast transcription factor Gal4 in the heart under control of the alpha-myosin heavy chain promoter and found that expression of this gene causes cardiomyopathy and HF, the severity of which correlated with the number of copies of the transgene integrated into the genome and with the expression level. A line with a single copy of the transgene targeted to the hprt locus correctly expressed the transgene but did not develop cardiomyopathy. Our results indicate that expression of a transgene in the heart may non-specifically cause HF in a dose-dependent manner.
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Affiliation(s)
- Petra E M H Habets
- Experimental and Molecular Cardiology Group, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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Misra RP, Bronson SK, Xiao Q, Garrison W, Li J, Zhao R, Duncan SA. Generation of single-copy transgenic mouse embryos directly from ES cells by tetraploid embryo complementation. BMC Biotechnol 2003; 1:12. [PMID: 11782291 PMCID: PMC64498 DOI: 10.1186/1472-6750-1-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2001] [Accepted: 12/18/2001] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Transgenic mice have been used extensively to analyze gene function. Unfortunately, traditional transgenic procedures have only limited use in analyzing alleles that cause lethality because lines of founder mice cannot be established. This is frustrating given that such alleles often reveal crucial aspects of gene function. For this reason techniques that facilitate the generation of embryos expressing such alleles would be of enormous benefit. Although the transient generation of transgenic embryos has allowed limited analysis of lethal alleles, it is expensive, time consuming and technically challenging. Moreover a fundamental limitation with this approach is that each embryo generated is unique and transgene expression is highly variable due to the integration of different transgene copy numbers at random genomic sites. RESULTS Here we describe an alternative method that allows the generation of clonal mouse embryos harboring a single-copy transgene at a defined genomic location. This was facilitated through the production of Hprt negative embryonic stem cells that allow the derivation of embryos by tetraploid embryo complementation. We show that targeting transgenes to the hprt locus in these ES cells by homologous recombination can be efficiently selected by growth in HAT medium. Moreover, embryos derived solely from targeted ES cells containing a single copy LacZ transgene under the control of the alpha-myosin heavy chain promoter exhibited the expected cardiac specific expression pattern. CONCLUSION Our results demonstrate that tetraploid embryo complementation by F3 hprt negative ES cells facilitates the generation of transgenic mouse embryos containing a single copy gene at a defined genomic locus. This approach is simple, extremely efficient and bypasses any requirement to generate chimeric mice. Moreover embryos generated by this procedure are clonal in that they are all derived from a single ES cell lines. This facilitates the comparative analysis of lethal alleles and thereby advances our ability to analyze gene function in mammals.
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Affiliation(s)
- Ravi P Misra
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd, WI 53226, USA
| | - Sarah K Bronson
- Department of Cellular and Molecular Physiology, The Penn State College of Medicine HI 66, The Milton S. Hershey Medical Center, 500 University Drive, Hershey, PA 17033-0850, USA
| | - Qi Xiao
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd, WI 53226, USA
| | - Wendy Garrison
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd, WI 53226, USA
| | - Jixuan Li
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd, WI 53226, USA
| | - Roong Zhao
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd, WI 53226, USA
| | - Stephen A Duncan
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd, WI 53226, USA
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A combinatorial network of evolutionarily conserved myelin basic protein regulatory sequences confers distinct glial-specific phenotypes. J Neurosci 2003. [PMID: 14614079 DOI: 10.1523/jneurosci.23-32-10214.2003] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Myelin basic protein (MBP) is required for normal myelin compaction and is implicated in both experimental and human demyelinating diseases. In this study, as an initial step in defining the regulatory network controlling MBP transcription, we located and characterized the function of evolutionarily conserved regulatory sequences. Long-range human-mouse sequence comparison revealed over 1 kb of conserved noncoding MBP 5' flanking sequence distributed into four widely spaced modules ranging from 0.1 to 0.4 kb. We demonstrate first that a controlled strategy of transgenesis provides an effective means to assign and compare qualitative and quantitative in vivo regulatory programs. Using this strategy, single-copy reporter constructs, designed to evaluate the regulatory significance of modular and intermodular sequences, were introduced by homologous recombination into the mouse hprt (hypoxanthine-guanine phosphoribosyltransferase) locus. The proximal modules M1 and M2 confer comparatively low-level oligodendrocyte expression primarily limited to early postnatal development, whereas the upstream M3 confers high-level oligodendrocyte expression extending throughout maturity. Furthermore, constructs devoid of M3 fail to target expression to newly myelinating oligodendrocytes in the mature CNS. Mutation of putative Nkx6.2/Gtx sites within M3, although not eliminating oligodendrocyte targeting, significantly decreases transgene expression levels. High-level and continuous expression is conferred to myelinating or remyelinating Schwann cells by M4. In addition, when isolated from surrounding MBP sequences, M3 confers transient expression to Schwann cells elaborating myelin. These observations define the in vivo regulatory roles played by conserved noncoding MBP sequences and lead to a combinatorial model in which different regulatory modules are engaged during primary myelination, myelin maintenance, and remyelination.
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Bockamp E, Maringer M, Spangenberg C, Fees S, Fraser S, Eshkind L, Oesch F, Zabel B. Of mice and models: improved animal models for biomedical research. Physiol Genomics 2002; 11:115-32. [PMID: 12464688 DOI: 10.1152/physiolgenomics.00067.2002] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The ability to engineer the mouse genome has profoundly transformed biomedical research. During the last decade, conventional transgenic and gene knockout technologies have become invaluable experimental tools for modeling genetic disorders, assigning functions to genes, evaluating drugs and toxins, and by and large helping to answer fundamental questions in basic and applied research. In addition, the growing demand for more sophisticated murine models has also become increasingly evident. Good state-of-principle knowledge about the enormous potential of second-generation conditional mouse technology will be beneficial for any researcher interested in using these experimental tools. In this review we will focus on practice, pivotal principles, and progress in the rapidly expanding area of conditional mouse technology. The review will also present an internet compilation of available tetracycline-inducible mouse models as tools for biomedical research (http://www.zmg.uni-mainz.de/tetmouse/).
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Affiliation(s)
- Ernesto Bockamp
- Laboratory of Molecular Mouse Genetics, Institute of Toxicology, Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany.
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Cvetkovic B, Keen HL, Zhang X, Davis D, Yang B, Sigmund CD. Physiological significance of two common haplotypes of human angiotensinogen using gene targeting in the mouse. Physiol Genomics 2002; 11:253-62. [PMID: 12388794 DOI: 10.1152/physiolgenomics.00076.2002] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiotensinogen (AGT) was the first gene to be genetically linked to hypertension in humans. Analysis of the gene sequence identified a number of polymorphisms, several of which were reported associated with increased blood pressure (BP) or other cardiovascular diseases. One haplotype of the human AGT (hAGT) gene consisting of an allele at the -6 (A vs. G) position in the promoter and the sequence encoding amino acid 235 (Thr vs. Met) attracted the most attention and has been the subject of numerous association studies. In this report, we addressed the physiological relevance of alleles at these two positions using an experimental mouse model system. Transgenic mice were generated by targeting each haplotype [-6G/235Met (GM) and -6A/235Thr (AT)] as a single copy transgene to the mouse hypoxanthine phosphoribosyl transferase locus, allowing direct comparison of the two transgenes in vivo. Our results indicate that both transgenes exhibit the same transcriptional activity and produce similar levels of hAGT protein in the plasma of the transgenic mice. BP analysis was performed in double transgenic mice generated by breeding each hAGT line to mice expressing a human renin gene. A small but significant increase in BP and relative heart weight was demonstrated by mice carrying the GM haplotype. Moreover, compensatory downregulation of endogenous renin expression was more pronounced in mice containing the GM variant. Our findings suggest that the AT and GM haplotypes of the hAGT gene have no effect on gene expression, but may affect the cardiovascular system and the regulation of BP differently.
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Affiliation(s)
- Branimir Cvetkovic
- Molecular Biology Interdisciplinary Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Misra RP, Duncan SA. Gene targeting in the mouse: advances in introduction of transgenes into the genome by homologous recombination. Endocrine 2002; 19:229-38. [PMID: 12624422 DOI: 10.1385/endo:19:3:229] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2002] [Accepted: 11/15/2002] [Indexed: 12/23/2022]
Abstract
The ability to stably introduce genes into the germline of animals provides a powerful means to address the genetic basis of physiology. Introduction of genes to generate transgenic animals has facilitated the development of complex genetic models of disease, as well as the in vivo study of gene function. However, one drawback of traditional transgenic technologies in which genes are microinjected into early-stage embryos is that there is little control over where and in how many copies genes are introduced into the genome. The development of animal transgenic technologies, which take advantage of homologous recombination mechanisms and the manipulation of embryonic stem (ES) cells, allows investigators to target and alter specific loci. In mouse transgenic systems, a plethora of sophisticated gene-targeting strategies now permit investigators to manipulate the genome in ways that essentially allow one to introduce virtually any desired change into the genome. Furthermore, when coupled with systems that allow for conditional gene expression, these gene-targeting strategies allow both temporal and tissue specific control of alterations to the genome. In the present review we briefly discuss some of the more recent gene-targeting strategies that have been developed to address the limitations of traditional animal transgenesis.
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Affiliation(s)
- Ravi P Misra
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee 53226, USA.
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34
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Tang SHE, Silva FJ, Tsark WMK, Mann JR. A Cre/loxP-deleter transgenic line in mouse strain 129S1/SvImJ. Genesis 2002; 32:199-202. [PMID: 11892008 DOI: 10.1002/gene.10030] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A Cre recombinase expression cassette was inserted into the X-linked Hprt locus by gene targeting in a mouse embryonic stem (ES) cell line isogenic to strain 129S1/SvImJ (129S1), then the transgene was introduced into 129S1 mice through ES cell chimeras. When females hemizygous for this transgene were mated to males carrying a neomycin selection cassette flanked by loxP sites, the cassette was always excised regardless of Cre inheritance and without detectable mosaicism. The usefulness of this "Cre-deleter" transgenic line is in its efficiency and defined genetic status in terms of mouse strain and location of the transgene.
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Affiliation(s)
- Shih-Huey E Tang
- Division of Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010-3011, USA
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35
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Van Den Oord EJ, Rowe DC. A step in another direction: looking for maternal genetic and environmental effects on racial differences in birth weight. Demography 2001; 38:573-6. [PMID: 11723954 DOI: 10.1353/dem.2001.0040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To advance research on birth weight differences between black and white infants, it may be useful to study maternal effects. These effects present a set of risk factors that are largely unrelated to those that are presently under investigation and fail to explain the gap in birth weight; empirical findings suggest their involvement. Although maternal effects can be environmental, as illustrated by recent findings, genetic effects could be important as well because gene frequencies are known to differ across the "racial" groups as studied by birth weight researchers, and maternal genes can exert a causal effect on birth weight.
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Affiliation(s)
- E J Van Den Oord
- Virginia Institute of Psychiatric and Behavioral Genetics, Virginia Commonwealth University, P.O. Box 980126, Richmond, VA 23298-0126, USA.
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