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PHEXL222P Mutation Increases Phex Expression in a New ENU Mouse Model for XLH Disease. Genes (Basel) 2022; 13:genes13081356. [PMID: 36011266 PMCID: PMC9407253 DOI: 10.3390/genes13081356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 02/02/2023] Open
Abstract
PhexL222P mouse is a new ENU mouse model for XLH disease due to Leu to Pro amino acid modification at position 222. PhexL222P mouse is characterized by growth retardation, hypophosphatemia, hypocalcemia, reduced body bone length, and increased epiphyseal growth plate thickness and femur diameter despite the increase in PHEXL222P expression. Actually, PhexL222P mice show an increase in Fgf23, Dmp1, and Mepe and Slc34a1 (Na-Pi IIa cotransporter) mRNA expression similar to those observed in Hyp mice. Femoral osteocalcin and sclerostin and Slc34a1 do not show any significant variation in PhexL222P mice. Molecular dynamics simulations support the experimental data. P222 might locally break the E217-Q224 β-sheet, which in turn might disrupt inter-β-sheet interactions. We can thus expect local protein misfolding, which might be responsible for the experimentally observed PHEXL222P loss of function. This model could be a valuable addition to the existing XLH model for further comprehension of the disease occurrence and testing of new therapies.
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2
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Investigation of TRPV1 loss-of-function phenotypes in TRPV1 Leu206Stop mice generated by N-ethyl-N-nitrosourea mutagenesis. Biochem Biophys Res Commun 2018; 500:456-461. [PMID: 29660342 DOI: 10.1016/j.bbrc.2018.04.102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 04/13/2018] [Indexed: 11/23/2022]
Abstract
N-ethyl-N-nitrosourea (ENU) random mutagenesis was used to generate a mouse model for the analysis of the transient receptor potential vanilloid 1 (TRPV1) cation channel. A transversion from T→A in exon 4 led to a Leu206Stop mutation generating a loss-of-function mutant. The TRPV1 agonist capsaicin was used to analyze functional and nociceptive parameters in vitro and in vivo in TRPV1 Leu206Stop mice and congenic C3HeB/FeJ controls. Capsaicin-induced [Ca2+]i changes in small diameter DRG neurons were significantly diminished in TRPV1 Leu206Stop mice and administration of capsaicin induced neither hypothermia nor nocifensive behaviour in vivo. TRPV1 Leu206Stop mice were tested in the spinal nerve ligation of mononeuropathic pain and developed mechanical hypersensitivity two weeks after nerve injury. In the open field test, a significant increase in spontaneous locomotion was detected in TRPV1 Leu206Stop mice as compared to wildtype controls. TRPV1 knockout mice have been reported to carry a similar phenotype regarding capsaicin-evoked responses in vitro and in vivo. However, in contrast to TRPV1 Leu206Stop mice, TRPV1 knockout mice did not differ in spontaneous locomotion as compared to congenic C57BL/6 mice, suggesting subtle ENU-dependent or independent strain differences between TRPV1 Leu206Stop mice and their wildtype controls. In summary, these data revealed a target-related (i.e. capsaicin-evoked) phenotype of TRPV1 Leu206Stop mice closely resembling that of published TRPV1 knockout mice. However, since ENU-mutant mice are congenic with the mouse strain initially used in random mutagenesis, direct phenotypic comparison with the respective wildtype controls is possible, and the time-consuming backcrossing in lines with targeted mutations is avoided.
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3
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Gallego-Llamas J, Timms AE, Pitstick R, Peters J, Carlson GA, Beier DR. Improvement of ENU Mutagenesis Efficiency Using Serial Injection and Mismatch Repair Deficiency Mice. PLoS One 2016; 11:e0159377. [PMID: 27441645 PMCID: PMC4956170 DOI: 10.1371/journal.pone.0159377] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/03/2016] [Indexed: 12/05/2022] Open
Abstract
ENU mutagenesis is a powerful method for generating novel lines of mice that are informative with respect to both fundamental biological processes and human disease. Rapid developments in genomic technology have made the task of identifying causal mutations by positional cloning remarkably efficient. One limitation of this approach remains the mutation frequency achievable using standard treatment protocols, which currently generate approximately 1–2 sequence changes per megabase when optimized. In this study we used two strategies to attempt to increase the number of mutations induced by ENU treatment. One approach employed mice carrying a mutation in the DNA repair enzyme Msh6. The second strategy involved injection of ENU to successive generations of mice. To evaluate the number of ENU-induced mutations, single mice or pooled samples were analyzed using whole exome sequencing. The results showed that there is considerable variability in the induced mutation frequency using these approaches, but an overall increase in ENU-induced variants from one generation to another was observed. The analysis of the mice deficient for Msh6 also showed an increase in the ENU-induced variants compared to the wild-type ENU-treated mice. However, in both cases the increase in ENU-induced mutation frequency was modest.
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Affiliation(s)
- Jabier Gallego-Llamas
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, United States of America
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, United States of America
| | - Andrew E. Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, United States of America
| | - Rose Pitstick
- McLaughlin Research Institute, Great Falls, MT, United States of America
| | - Janet Peters
- McLaughlin Research Institute, Great Falls, MT, United States of America
| | - George A. Carlson
- McLaughlin Research Institute, Great Falls, MT, United States of America
| | - David R. Beier
- Center for Developmental Biology and Regenerative Medicine, Seattle Children’s Research Institute, Seattle, WA, United States of America
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, United States of America
- * E-mail:
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4
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El Hakam Kamareddin C, Magnol L, Blanquet V. A new Otogelin ENU mouse model for autosomal-recessive nonsyndromic moderate hearing impairment. SPRINGERPLUS 2015; 4:730. [PMID: 26636018 PMCID: PMC4659790 DOI: 10.1186/s40064-015-1537-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 11/13/2015] [Indexed: 02/03/2023]
Abstract
Approximately 10 % of the population worldwide suffers from hearing loss (HL) and about 60 % of persons with early onset HL have hereditary hearing loss due to genetic mutations. Highly efficient mutagenesis in mice with the chemical mutagen, ethylnitrosourea (ENU), associated with relevant phenotypic tools represents a powerful approach in producing mouse models for hearing impairment. A benefit of this strategy is to generate alleles to form a series revealing the full spectrum of gene function in vivo. It can also mimic the range of human mutations and polymorphisms for HL. In the course of a genome ENU mutagenesis program, we selected a new mouse model for hearing defect based on a dysmorphological screen. We identified by gene mapping the mutation responsible for this phenotype and characterized it at the histological level of the inner ear and evaluated the vestibule by following the recommendations of the standard operating procedures, IMPReSS. We have identified and characterized a new recessive allele of the otogelin gene, Otogvbd/vbd, due to a homozygous one base pair substitution at the splice donor site of intron 29. This mutation leads to a frame-shift and a premature stop codon. We observed a decrease in the amount of sensory cells in the maculae of Otogvbd/vbd mice as well as an apparent drastically decreased density to almost absence of the otoconial membrane. Compared to Otogtm1Prs and twister, the two other existing otogelin alleles, the detailed analysis of Otogvbd/vbd revealed that these mice share some common behavioural characteristics either with Otogtm1Prs or twister whereas the fine vestibular phenotype and the hearing defect are different. Our results emphasize the importance of detecting and characterizing a new allele of a gene in order to get comprehensive information about the gene function.
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Affiliation(s)
- Carole El Hakam Kamareddin
- Univ. Limoges, INRA, UMR 1061, Unité de Génétique Moléculaire Animale, Faculté des Sciences et Techniques, 123, Avenue Albert Thomas, 87060 Limoges, France
| | - Laetitia Magnol
- Univ. Limoges, INRA, UMR 1061, Unité de Génétique Moléculaire Animale, Faculté des Sciences et Techniques, 123, Avenue Albert Thomas, 87060 Limoges, France
| | - Veronique Blanquet
- Univ. Limoges, INRA, UMR 1061, Unité de Génétique Moléculaire Animale, Faculté des Sciences et Techniques, 123, Avenue Albert Thomas, 87060 Limoges, France
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5
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Kedzierski L, Linossi EM, Kolesnik TB, Day EB, Bird NL, Kile BT, Belz GT, Metcalf D, Nicola NA, Kedzierska K, Nicholson SE. Suppressor of cytokine signaling 4 (SOCS4) protects against severe cytokine storm and enhances viral clearance during influenza infection. PLoS Pathog 2014; 10:e1004134. [PMID: 24809749 PMCID: PMC4014316 DOI: 10.1371/journal.ppat.1004134] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 04/04/2014] [Indexed: 11/18/2022] Open
Abstract
Suppressor of cytokine signaling (SOCS) proteins are key regulators of innate and adaptive immunity. There is no described biological role for SOCS4, despite broad expression in the hematopoietic system. We demonstrate that mice lacking functional SOCS4 protein rapidly succumb to infection with a pathogenic H1N1 influenza virus (PR8) and are hypersusceptible to infection with the less virulent H3N2 (X31) strain. In SOCS4-deficient animals, this led to substantially greater weight loss, dysregulated pro-inflammatory cytokine and chemokine production in the lungs and delayed viral clearance. This was associated with impaired trafficking of influenza-specific CD8 T cells to the site of infection and linked to defects in T cell receptor activation. These results demonstrate that SOCS4 is a critical regulator of anti-viral immunity. The suppressor of cytokine signaling proteins are key regulators of immunity. As yet there is no described biological role for SOCS4, despite its broad expression in cells of the immune system. Given the important role of other SOCS proteins in controlling the immune response, we have generated SOCS4-mutant mice and used a mouse influenza infection model to investigate the biological function of SOCS4. We demonstrate that mice lacking SOCS4 rapidly succumb to infection with a pathogenic H1N1 influenza virus and are hypersusceptible to infection with the less virulent H3N2 strain. This is the first demonstration of a functional phenotype in SOCS4-deficient mice. Our study reveals that in SOCS4-deficient animals, there is a dysregulated pro-inflammatory cytokine and chemokine production in the lungs and delayed viral clearance. This is associated with impaired trafficking of virus-specific CD8 T cells to the site of infection and linked to defects in T cell receptor activation. These results demonstrate that SOCS4 is a critical regulator of anti-viral immunity. Understanding the regulation of the inflammatory response to influenza is particularly relevant given the current climate concerning pandemic influenza outbreaks.
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Affiliation(s)
- Lukasz Kedzierski
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
- * E-mail: (LK); (SEN)
| | - Edmond M. Linossi
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Tatiana B. Kolesnik
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - E. Bridie Day
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Nicola L. Bird
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Benjamin T. Kile
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Gabrielle T. Belz
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Donald Metcalf
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Nicos A. Nicola
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Katherine Kedzierska
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Sandra E. Nicholson
- Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, Victoria Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
- * E-mail: (LK); (SEN)
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6
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Absence of cardiovascular manifestations in a haploinsufficient Tgfbr1 mouse model. PLoS One 2014; 9:e89749. [PMID: 24587008 PMCID: PMC3933654 DOI: 10.1371/journal.pone.0089749] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/23/2014] [Indexed: 01/22/2023] Open
Abstract
Loeys-Dietz syndrome (LDS) is an autosomal dominant arterial aneurysm disease belonging to the spectrum of transforming growth factor β (TGFβ)-associated vasculopathies. In its most typical form it is characterized by the presence of hypertelorism, bifid uvula/cleft palate and aortic aneurysm and/or arterial tortuosity. LDS is caused by heterozygous loss of function mutations in the genes encoding TGFβ receptor 1 and 2 (TGFBR1 and −2), which lead to a paradoxical increase in TGFβ signaling. To address this apparent paradox and to gain more insight into the pathophysiology of aneurysmal disease, we characterized a new Tgfbr1 mouse model carrying a p.Y378* nonsense mutation. Study of the natural history in this model showed that homozygous mutant mice die during embryonic development due to defective vascularization. Heterozygous mutant mice aged 6 and 12 months were morphologically and (immuno)histochemically indistinguishable from wild-type mice. We show that the mutant allele is degraded by nonsense mediated mRNA decay, expected to result in haploinsufficiency of the mutant allele. Since this haploinsufficiency model does not result in cardiovascular malformations, it does not allow further study of the process of aneurysm formation. In addition to providing a comprehensive method for cardiovascular phenotyping in mice, the results of this study confirm that haploinsuffciency is not the underlying genetic mechanism in human LDS.
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The Justy mutant mouse strain produces a spontaneous murine model of salivary gland cancer with myoepithelial and basal cell differentiation. J Transl Med 2013; 93:711-9. [PMID: 23608756 PMCID: PMC3669254 DOI: 10.1038/labinvest.2013.62] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We previously identified a novel mutant mouse strain on the C3HeB/FeJ background named Justy. This strain bears a recessive mutation in the Gon4l gene that greatly reduces expression of the encoded protein, a nuclear factor implicated in transcriptional regulation. Here, we report that Justy mutant mice aged 6 months or older spontaneously developed carcinomas with myoepithelial and basaloid differentiation in salivary glands with an incidence of ∼25%. Tumors developed proximate to submandibular glands and to a lesser extent in the sublingual and parotid glands. Histologically, tumors often had central cavitary lesions filled with necrotic debris that were lined by tumor cells, and had spindle and epithelioid cell differentiation with lesser basaloid to clear cell features. Tumor tissue often had variable evidence of a high mitotic rate, pleomorphism, and invasion into adjacent salivary glands. Neoplastic cells had diffuse immunoreactivity for pancytokeratin (AE1/AE3) and p63. Although CK5/6 immunostaining was seen in the much of the tumor cells, it was often lacking in pleomorphic areas. Tumor cells lacked immunoreactivity for alpha-smooth muscle actin, S100, c-Kit, and glial fibrillary acid protein. In addition, tumors had immunoreactivity for phosphorylated and total epidermal growth factor receptor, suggesting that EGFR signaling may participate in growth regulation of these tumors. These findings indicate that the salivary gland carcinomas occur spontaneously in Justy mice, and that these tumors may offer a valuable model for study of EGFR regulation. In combination, our data suggest that Justy mice warrant further investigation for use as a mouse model for human salivary gland neoplasia.
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Liu Y, Bartlett JA, Di ME, Bomberger JM, Chan YR, Gakhar L, Mallampalli RK, McCray PB, Di YP. SPLUNC1/BPIFA1 contributes to pulmonary host defense against Klebsiella pneumoniae respiratory infection. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:1519-31. [PMID: 23499554 DOI: 10.1016/j.ajpath.2013.01.050] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 01/10/2013] [Accepted: 01/14/2013] [Indexed: 12/12/2022]
Abstract
Epithelial host defense proteins comprise a critical component of the pulmonary innate immune response to infection. The short palate, lung, nasal epithelium clone (PLUNC) 1 (SPLUNC1) protein is a member of the bactericidal/permeability-increasing (BPI) fold-containing (BPIF) protein family, sharing structural similarities with BPI-like proteins. SPLUNC1 is a 25 kDa secretory protein that is expressed in nasal, oropharyngeal, and lung epithelia, and has been implicated in airway host defense against Pseudomonas aeruginosa and other organisms. SPLUNC1 is reported to have surfactant properties, which may contribute to anti-biofilm defenses. The objective of this study was to assess the importance of SPLUNC1 surfactant activity in airway epithelial secretions and to explore its biological relevance in the context of a bacterial infection model. Using cultured airway epithelia, we confirmed that SPLUNC1 is critically important for maintenance of low surface tension in airway fluids. Furthermore, we demonstrated that recombinant SPLUNC1 (rSPLUNC1) significantly inhibited Klebsiella pneumoniae biofilm formation on airway epithelia. We subsequently found that Splunc1(-/-) mice were significantly more susceptible to infection with K. pneumoniae, confirming the likely in vivo relevance of this anti-biofilm effect. Our data indicate that SPLUNC1 is a crucial component of mucosal innate immune defense against pulmonary infection by a relevant airway pathogen, and provide further support for the novel hypothesis that SPLUNC1 protein prevents bacterial biofilm formation through its ability to modulate surface tension of airway fluids.
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Affiliation(s)
- Yang Liu
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
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9
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Mariotta L, Ramadan T, Singer D, Guetg A, Herzog B, Stoeger C, Palacín M, Lahoutte T, Camargo SMR, Verrey F. T-type amino acid transporter TAT1 (Slc16a10) is essential for extracellular aromatic amino acid homeostasis control. J Physiol 2012; 590:6413-24. [PMID: 23045339 DOI: 10.1113/jphysiol.2012.239574] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The uniporter TAT1 (Slc16a10) mediates the facilitated diffusion of aromatic amino acids (AAAs) across basolateral membranes of kidney, small intestine and liver epithelial cells, and across the plasma membrane of non-epithelial cells like skeletal myocytes. Its role for body AA homeostasis has now been investigated using newly generated TAT1 (Slc16a10) defective mice (tat1(-/-)). These mice grow and reproduce normally, show no gross phenotype and no obvious neurological defect. Histological analysis did not reveal abnormalities and there is no compensatory change in any tested AA transporter mRNA. TAT1 null mice, however, display increased plasma, muscle and kidney AAA concentration under both normal and high protein diet, although this concentration remains normal in the liver. A major aromatic aminoaciduria and a smaller urinary loss of all substrates additionally transported by l-type AA antiporter Lat2-4F2hc (Slc7a8) were revealed under a high protein diet. This suggests an epithelial transport defect as also shown by the accumulation of intravenously injected (123)I-2-I-l-Phe in kidney and l-[(3)H]Phe in ex vivo everted gut sac enterocytes. Taken together, these data indicate that the uniporter TAT1 is required to equilibrate the concentration of AAAs across specific membranes. For instance, it enables hepatocytes to function as a sink that controls the extracellular AAAs concentration. Additionally, it facilitates the release of AAAs across the basolateral membrane of small intestine and proximal kidney tubule epithelial cells, thereby allowing the efflux of other neutral AAs presumably via Lat2-4F2hc.
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Affiliation(s)
- Luca Mariotta
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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10
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Zheng S, Geghman K, Shenoy S, Li C. Retake the center stage--new development of rat genetics. J Genet Genomics 2012; 39:261-8. [PMID: 22749013 DOI: 10.1016/j.jgg.2012.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 05/02/2012] [Accepted: 05/02/2012] [Indexed: 10/28/2022]
Abstract
The rat is a powerful model for the study of human physiology and diseases, and is preferred by physiologists, neuroscientists and toxicologists. However, the lack of robust genetic modification tools has severely limited the generation of rat genetic models over the last two decades. In the last few years, several gene-targeting strategies have been developed in rats using N-ethyl-N-nitrosourea (ENU), transposons, zinc-finger nucleases (ZFNs), bacterial artificial chromosome (BAC) mediated transgenesis, and recently established rat embryonic stem (ES) cells. The development and improvement of these approaches to genetic manipulation have created a bright future for the use of genetic rat models in investigations of gene function and human diseases. Here, we summarize the strategies used for rat genetic manipulation in current research. We also discuss BAC transgenesis as a potential tool in rat transgenic models.
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Affiliation(s)
- Sushuang Zheng
- Department of Neurology, Friedman Brain Institute, Mt. Sinai School of Medicine, Box 1137, New York, NY 10029, USA
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11
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Chen D, Li S, Singh R, Spinette S, Sedlmeier R, Epstein HF. Dual function of the UNC-45b chaperone with myosin and GATA4 in cardiac development. J Cell Sci 2012; 125:3893-903. [PMID: 22553207 DOI: 10.1242/jcs.106435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cardiac development requires interplay between the regulation of gene expression and the assembly of functional sarcomeric proteins. We report that UNC-45b recessive loss-of-function mutations in C3H and C57BL/6 inbred mouse strains cause arrest of cardiac morphogenesis at the formation of right heart structures and failure of contractile function. Wild-type C3H and C57BL/6 embryos at the same stage, E9.5, form actively contracting right and left atria and ventricles. The known interactions of UNC-45b as a molecular chaperone are consistent with diminished accumulation of the sarcomeric myosins, but not their mRNAs, and the resulting decreased contraction of homozygous mutant embryonic hearts. The novel finding that GATA4 accumulation is similarly decreased at the protein but not mRNA levels is also consistent with the function of UNC-45b as a chaperone. The mRNAs of known downstream targets of GATA4 during secondary cardiac field development, the cardiogenic factors Hand1, Hand2 and Nkx-2.5, are also decreased, consistent with the reduced GATA4 protein accumulation. Direct binding studies show that the UNC-45b chaperone forms physical complexes with both the alpha and beta cardiac myosins and the cardiogenic transcription factor GATA4. Co-expression of UNC-45b with GATA4 led to enhanced transcription from GATA promoters in naïve cells. These novel results suggest that the heart-specific UNC-45b isoform functions as a molecular chaperone mediating contractile function of the sarcomere and gene expression in cardiac development.
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Affiliation(s)
- Daisi Chen
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, TX 77555-0641, USA
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12
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Fenner D, Odili S, Hong HK, Kobayashi Y, Kohsaka A, Siepka SM, Vitaterna MH, Chen P, Zelent B, Grimsby J, Takahashi JS, Matschinsky FM, Bass J. Generation of N-ethyl-N-nitrosourea (ENU) diabetes models in mice demonstrates genotype-specific action of glucokinase activators. J Biol Chem 2011; 286:39560-72. [PMID: 21921030 PMCID: PMC3234779 DOI: 10.1074/jbc.m111.269100] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/16/2011] [Indexed: 11/06/2022] Open
Abstract
We performed genome-wide mutagenesis in C57BL/6J mice using N-ethyl-N-nitrosourea to identify mutations causing high blood glucose early in life and to produce new animal models of diabetes. Of a total of 13 new lines confirmed by heritability testing, we identified two semi-dominant pedigrees with novel missense mutations (Gck(K140E) and Gck(P417R)) in the gene encoding glucokinase (Gck), the mammalian glucose sensor that is mutated in human maturity onset diabetes of the young type 2 and the target of emerging anti-hyperglycemic agents that function as glucokinase activators (GKAs). Diabetes phenotype corresponded with genotype (mild-to-severe: Gck(+/+) < Gck(P417R/+), Gck(K140E)(/+) < Gck(P417R/P417R), Gck(P417R/K140E), and Gck(K140E/K140E)) and with the level of expression of GCK in liver. Each mutant was produced as the recombinant enzyme in Escherichia coli, and analysis of k(cat) and tryptophan fluorescence (I(320/360)) during thermal shift unfolding revealed a correlation between thermostability and the severity of hyperglycemia in the whole animal. Disruption of the glucokinase regulatory protein-binding site (GCK(K140E)), but not the ATP binding cassette (GCK(P417R)), prevented inhibition of enzyme activity by glucokinase regulatory protein and corresponded with reduced responsiveness to the GKA drug. Surprisingly, extracts from liver of diabetic GCK mutants inhibited activity of the recombinant enzyme, a property that was also observed in liver extracts from mice with streptozotocin-induced diabetes. These results indicate a relationship between genotype, phenotype, and GKA efficacy. The integration of forward genetic screening and biochemical profiling opens a pathway for preclinical development of mechanism-based diabetes therapies.
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Affiliation(s)
- Deborah Fenner
- From the Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
- the Department of Neurobiology and Physiology and
| | - Stella Odili
- the Department of Biochemistry and Biophysics, Children's Hospital of Pennsylvania and Diabetes Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Hee-Kyung Hong
- the Department of Neurobiology and Physiology and
- the Center for Sleep and Circadian Biology, Northwestern University, Evanston, Illinois 60208
| | - Yumiko Kobayashi
- From the Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
- the Department of Neurobiology and Physiology and
| | - Akira Kohsaka
- the Department of Neurobiology and Physiology and
- the Departments of Medicine and Physiology II, Wakayama Medical University, Wakayama City, 640-8265, Japan
| | - Sandra M. Siepka
- the Department of Neurobiology and Physiology and
- the Center for Sleep and Circadian Biology, Northwestern University, Evanston, Illinois 60208
| | - Martha H. Vitaterna
- the Department of Neurobiology and Physiology and
- the Center for Sleep and Circadian Biology, Northwestern University, Evanston, Illinois 60208
| | - Pan Chen
- the Department of Biochemistry and Biophysics, Children's Hospital of Pennsylvania and Diabetes Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Bogumil Zelent
- the Department of Biochemistry and Biophysics, Children's Hospital of Pennsylvania and Diabetes Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Joseph Grimsby
- the Department of Metabolic Diseases, Hoffmann-La Roche, Nutley, New Jersey 07110
| | - Joseph S. Takahashi
- the Department of Neurobiology and Physiology and
- the Department of Neuroscience and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, and
| | - Franz M. Matschinsky
- the Department of Biochemistry and Biophysics, Children's Hospital of Pennsylvania and Diabetes Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Joseph Bass
- From the Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
- the Department of Neurobiology and Physiology and
- the Center for Sleep and Circadian Biology, Northwestern University, Evanston, Illinois 60208
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13
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Alexandru A, Jagla W, Graubner S, Becker A, Bäuscher C, Kohlmann S, Sedlmeier R, Raber KA, Cynis H, Rönicke R, Reymann KG, Petrasch-Parwez E, Hartlage-Rübsamen M, Waniek A, Rossner S, Schilling S, Osmand AP, Demuth HU, von Hörsten S. Selective hippocampal neurodegeneration in transgenic mice expressing small amounts of truncated Aβ is induced by pyroglutamate-Aβ formation. J Neurosci 2011; 31:12790-801. [PMID: 21900558 PMCID: PMC6623394 DOI: 10.1523/jneurosci.1794-11.2011] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 07/09/2011] [Accepted: 07/12/2011] [Indexed: 12/24/2022] Open
Abstract
Posttranslational amyloid-β (Aβ) modification is considered to play an important role in Alzheimer's disease (AD) etiology. An N-terminally modified Aβ species, pyroglutamate-amyloid-β (pE3-Aβ), has been described as a major constituent of Aβ deposits specific to human AD but absent in normal aging. Formed via cyclization of truncated Aβ species by glutaminyl cyclase (QC; QPCT) and/or its isoenzyme (isoQC; QPCTL), pE3-Aβ aggregates rapidly and is known to seed additional Aβ aggregation. To directly investigate pE3-Aβ toxicity in vivo, we generated and characterized transgenic TBA2.1 and TBA2.2 mice, which express truncated mutant human Aβ. Along with a rapidly developing behavioral phenotype, these mice showed progressively accumulating Aβ and pE3-Aβ deposits in brain regions of neuronal loss, impaired long-term potentiation, microglial activation, and astrocytosis. Illustrating a threshold for pE3-Aβ neurotoxicity, this phenotype was not found in heterozygous animals but in homozygous TBA2.1 or double-heterozygous TBA2.1/2.2 animals only. A significant amount of pE3-Aβ formation was shown to be QC-dependent, because crossbreeding of TBA2.1 with QC knock-out, but not isoQC knock-out, mice significantly reduced pE3-Aβ levels. Hence, lowering the rate of QC-dependent posttranslational pE3-Aβ formation can, in turn, lower the amount of neurotoxic Aβ species in AD.
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MESH Headings
- Aging/pathology
- Aging/psychology
- Alzheimer Disease/pathology
- Amyloid beta-Protein Precursor/biosynthesis
- Animals
- Behavior, Animal
- Brain/pathology
- Enzyme-Linked Immunosorbent Assay
- Gliosis/pathology
- Heredodegenerative Disorders, Nervous System/genetics
- Heredodegenerative Disorders, Nervous System/pathology
- Heredodegenerative Disorders, Nervous System/psychology
- Hippocampus/pathology
- Humans
- Immunohistochemistry
- Kinetics
- Long-Term Potentiation/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Transgenic
- Microscopy, Electron
- Neuronal Plasticity/genetics
- Neuronal Plasticity/physiology
- Phenotype
- Postural Balance/physiology
- Protein Processing, Post-Translational
- Pyrrolidonecarboxylic Acid/metabolism
- Reflex, Startle/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
| | | | | | | | | | | | | | - Kerstin A. Raber
- Experimental Therapy, Friedrich Alexander University Erlangen Nürnberg, 91054 Erlangen, Germany
| | | | - Raik Rönicke
- German Center of Neurodegenerative Diseases, 39120 Magdeburg, Germany
| | - Klaus G. Reymann
- German Center of Neurodegenerative Diseases, 39120 Magdeburg, Germany
- Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | | | - Maike Hartlage-Rübsamen
- Paul Flechsig Institute for Brain Research, University of Leipzig, 04109 Leipzig, Germany, and
| | - Alexander Waniek
- Paul Flechsig Institute for Brain Research, University of Leipzig, 04109 Leipzig, Germany, and
| | - Steffen Rossner
- Paul Flechsig Institute for Brain Research, University of Leipzig, 04109 Leipzig, Germany, and
| | | | - Alexander P. Osmand
- Department of Medicine, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee 37920
| | - Hans-Ulrich Demuth
- Ingenium Pharmaceuticals, 82152 Martinsried, Germany
- Probiodrug, 06120 Halle/Saale, Germany
| | - Stephan von Hörsten
- Experimental Therapy, Friedrich Alexander University Erlangen Nürnberg, 91054 Erlangen, Germany
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14
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Cynis H, Hoffmann T, Friedrich D, Kehlen A, Gans K, Kleinschmidt M, Rahfeld JU, Wolf R, Wermann M, Stephan A, Haegele M, Sedlmeier R, Graubner S, Jagla W, Müller A, Eichentopf R, Heiser U, Seifert F, Quax PHA, de Vries MR, Hesse I, Trautwein D, Wollert U, Berg S, Freyse EJ, Schilling S, Demuth HU. The isoenzyme of glutaminyl cyclase is an important regulator of monocyte infiltration under inflammatory conditions. EMBO Mol Med 2011; 3:545-58. [PMID: 21774078 PMCID: PMC3377097 DOI: 10.1002/emmm.201100158] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/01/2011] [Accepted: 06/08/2011] [Indexed: 02/06/2023] Open
Abstract
Acute and chronic inflammatory disorders are characterized by detrimental cytokine and chemokine expression. Frequently, the chemotactic activity of cytokines depends on a modified N-terminus of the polypeptide. Among those, the N-terminus of monocyte chemoattractant protein 1 (CCL2 and MCP-1) is modified to a pyroglutamate (pE-) residue protecting against degradation in vivo. Here, we show that the N-terminal pE-formation depends on glutaminyl cyclase activity. The pE-residue increases stability against N-terminal degradation by aminopeptidases and improves receptor activation and signal transduction in vitro. Genetic ablation of the glutaminyl cyclase iso-enzymes QC (QPCT) or isoQC (QPCTL) revealed a major role of isoQC for pE1-CCL2 formation and monocyte infiltration. Consistently, administration of QC-inhibitors in inflammatory models, such as thioglycollate-induced peritonitis reduced monocyte infiltration. The pharmacologic efficacy of QC/isoQC-inhibition was assessed in accelerated atherosclerosis in ApoE3*Leiden mice, showing attenuated atherosclerotic pathology following chronic oral treatment. Current strategies targeting CCL2 are mainly based on antibodies or spiegelmers. The application of small, orally available inhibitors of glutaminyl cyclases represents an alternative therapeutic strategy to treat CCL2-driven disorders such as atherosclerosis/restenosis and fibrosis.
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15
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Wagner S, Calzada-Wack J, Rosemann M, Becker L, Tost M, Silva-Buttkus P, Klein-Rodewald T, Fuchs H, Neff F, Hrabé de Angelis M, Esposito I. [Characterization of ENU-mutant mice. Animal models for human diseases using morphological and molecular methods]. DER PATHOLOGE 2011; 31 Suppl 2:147-52. [PMID: 20835709 DOI: 10.1007/s00292-010-1347-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Following sequencing of the human genome there are new challenges to decipher the knowledge concerning gene function and the role of gene interactions and pathways leading to disease. Mouse models have proven to be an ideal tool for this purpose. Point mutations induced by chemical mutagenesis by N-ethyl-N-nitrosourea (ENU) offer possibilities for the analysis of the phenotypic outcome of a single base pair exchange on the entire organism. The Munich ENU mouse mutagenesis project is part of the worldwide efforts to obtain mutations for each gene. The generation of new alleles or allelic series offers relevant insights into the relevance of single gene sections. Various mouse models for human diseases have been generated by a systematic large-scale genome-wide phenotyping screen in the last decade. This work illustrates how the implementation of the ENU mouse mutagenesis project with gene identification and parallel high-throughput screening is taking advantage of local cooperation with experienced phenotyping groups at the Helmholtz Zentrum München, leading to major advances in the functional analysis of the mammalian genome.
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Affiliation(s)
- S Wagner
- Institut für Experimentelle Genetik, München
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16
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Abstract
The generation of genetically modified animals using N-ethyl-N-nitrosourea (ENU) mutagenesis is a fast and highly effective method. The technique is based on treating male animals with the supermutagen ENU, which randomly introduces mutations in the spermatogonial stem cells. By breeding these animals with untreated females, an F1 population is generated in which each individual carries unique random ENU-induced mutations, which can be retrieved using either genotype-driven or phenotype-driven approaches. No complicated cell culturing techniques are required and since no foreign DNA is introduced, the mutant animals that are generated are not transgenic. Here, we describe the detailed protocols for ENU mutagenesis and for mutant retrieval.
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17
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Spyroglou A, Wagner S, Gomez-Sanchez C, Rathkolb B, Wolf E, Manolopoulou J, Reincke M, Bidlingmaier M, Hrabé de Angelis M, Beuschlein F. Utilization of a mutagenesis screen to generate mouse models of hyperaldosteronism. Endocrinology 2011; 152:326-31. [PMID: 21068155 DOI: 10.1210/en.2010-1081] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Primary aldosteronism is considered to be responsible for almost 10% of all cases of arterial hypertension. The genetic background of this common disease, however, has been elucidated only for the rare familial types, whereas in the large majority of sporadic cases, underlying mechanisms still remain unclear. In an attempt to define novel genetic loci involved in the pathophysiology of primary aldosteronism, a mutagenesis screen after treatment of mice with the alkylating agent N-ethyl-N-nitrosourea was established for the parameter aldosterone. As the detection method we used a time-resolved fluorescence immunoassay that allows the measurement of aldosterone in very small murine sample volumes. Based on this assay, we first determined the normal aldosterone values for wild-type C3HeB/FeJ mice under baseline conditions [92 ± 6 pg/ml for females (n = 69) and 173 ± 16 pg/ml for males (n = 55)]. Subsequently, aldosterone measurement was carried out in more than 2800 F(1) offspring of chemically mutagenized C3HeB/FeJ mice, and values were compared with aldosterone levels from untreated animals. Persistent hyperaldosteronism (defined as levels +3 sd above the mean of untreated animals) upon repeated measurements was present in seven female and two male F(1) offspring. Further breeding of these founders gave rise to F(2) pedigrees from which eight lines with different patterns of inheritance of hyperaldosteronism could be established. These animals will serve for detailed phenotypic and genetic characterization in the future. Taken together, our data demonstrate the feasibility of a phenotype-driven mutagenesis screen to detect and establish mutant mouse lines with a phenotype of chronic hyperaldosteronism.
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Affiliation(s)
- Ariadni Spyroglou
- Department of Medicine, Endocrine Research, University Hospital Innenstadt, Ziemssenstr. 1, D-80336 Munich, Germany
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18
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Nguyen N, Judd LM, Kalantzis A, Whittle B, Giraud AS, van Driel IR. Random mutagenesis of the mouse genome: a strategy for discovering gene function and the molecular basis of disease. Am J Physiol Gastrointest Liver Physiol 2011; 300:G1-11. [PMID: 20947703 PMCID: PMC3774088 DOI: 10.1152/ajpgi.00343.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mutagenesis of mice with N-ethyl-N-nitrosourea (ENU) is a phenotype-driven approach to unravel gene function and discover new biological pathways. Phenotype-driven approaches have the advantage of making no assumptions about the function of genes and their products and have been successfully applied to the discovery of novel gene-phenotype relationships in many physiological systems. ENU mutagenesis of mice is used in many large-scale and more focused projects to generate and identify novel mouse models for the study of gene functions and human disease. This review examines the strategies and tools used in ENU mutagenesis screens to efficiently generate and identify functional mutations.
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Affiliation(s)
- Nhung Nguyen
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne;
| | - Louise M. Judd
- 2Gastrointestinal Research in Inflammation and Pathology Laboratory, Murdoch Children's Research Institute, Melbourne; and
| | - Anastasia Kalantzis
- 2Gastrointestinal Research in Inflammation and Pathology Laboratory, Murdoch Children's Research Institute, Melbourne; and
| | - Belinda Whittle
- 3Australian Phenomics Facility, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Andrew S. Giraud
- 2Gastrointestinal Research in Inflammation and Pathology Laboratory, Murdoch Children's Research Institute, Melbourne; and
| | - Ian R. van Driel
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne;
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19
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Lee YC, Chang CJ, Bali D, Chen YT, Yan YT. Glycogen-branching enzyme deficiency leads to abnormal cardiac development: novel insights into glycogen storage disease IV. Hum Mol Genet 2010; 20:455-65. [DOI: 10.1093/hmg/ddq492] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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20
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Jamsai D, O'Bryan MK. Genome-wide ENU mutagenesis for the discovery of novel male fertility regulators. Syst Biol Reprod Med 2010; 56:246-59. [PMID: 20536324 DOI: 10.3109/19396361003706424] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The completion of genome sequencing projects has provided an extensive knowledge of the contents of the genomes of human, mouse, and many other organisms. Despite this, the function of most of the estimated 25,000 human genes remains largely unknown. Attention has now turned to elucidating gene function and identifying biological pathways that contribute to human diseases, including male infertility. Our understanding of the genetic regulation of male fertility has been accelerated through the use of genetically modified mouse models including knockout, knock-in, gene-trapped, and transgenic mice. Such reverse genetic approaches however, require some fore-knowledge of a gene's function and, as such, bias against the discovery of completely novel genes and biological pathways. To facilitate high throughput gene discovery, genome-wide mouse mutagenesis via the use of a potent chemical mutagen, N-ethyl-N-nitrosourea (ENU), has been developed over the past decade. This forward genetic, or phenotype-driven, approach relies upon observing a phenotype first, then subsequently defining the underlining genetic defect. Mutations are randomly introduced into the mouse genome via ENU exposure. Through a controlled breeding scheme, mutations causing a phenotype of interest (e.g., male infertility) are then identified by linkage analysis and candidate gene sequencing. This approach allows for the possibility of revealing comprehensive phenotype-genotype relationships for a range of genes and pathways i.e. in addition to null alleles, mice containing partial loss of function or gain-of-function mutations, can be recovered. Such point mutations are likely to be more reflective of those that occur within the human population. Many research groups have successfully used this approach to generate infertile mouse lines and some novel male fertility genes have been revealed. In this review, we focus on the utility of ENU mutagenesis for the discovery of novel male fertility regulators.
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Affiliation(s)
- Duangporn Jamsai
- The Department of Anatomy and Developmental Biology and The Australian Research Council (ARC) Centre of Excellence in Biotechnology and Development, Monash University, Melbourne, Victoria, Australia
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21
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Now and future of mouse mutagenesis for human disease models. J Genet Genomics 2010; 37:559-72. [DOI: 10.1016/s1673-8527(09)60076-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/30/2010] [Accepted: 07/31/2010] [Indexed: 11/20/2022]
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22
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Lu P, Hankel IL, Knisz J, Marquardt A, Chiang MY, Grosse J, Constien R, Meyer T, Schroeder A, Zeitlmann L, Al-Alem U, Friedman AD, Elliott EI, Meyerholz DK, Waldschmidt TJ, Rothman PB, Colgan JD. The Justy mutation identifies Gon4-like as a gene that is essential for B lymphopoiesis. ACTA ACUST UNITED AC 2010; 207:1359-67. [PMID: 20530203 PMCID: PMC2901076 DOI: 10.1084/jem.20100147] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A recessive mutation named Justy was found that abolishes B lymphopoiesis but does not impair other major aspects of hematopoiesis. Transplantation experiments showed that homozygosity for Justy prevented hematopoietic progenitors from generating B cells but did not affect the ability of bone marrow stroma to support B lymphopoiesis. In bone marrow from mutant mice, common lymphoid progenitors and pre-pro–B cells appeared normal, but cells at subsequent stages of B lymphopoiesis were dramatically reduced in number. Under culture conditions that promoted B lymphopoiesis, mutant pre-pro–B cells remained alive and began expressing the B cell marker CD19 but failed to proliferate. In contrast, these cells were able to generate myeloid or T/NK precursors. Genetic and molecular analysis demonstrated that Justy is a point mutation within the Gon4-like (Gon4l) gene, which encodes a protein with homology to transcriptional regulators. This mutation was found to disrupt Gon4l pre-mRNA splicing and dramatically reduce expression of wild-type Gon4l RNA and protein. Consistent with a role for Gon4l in transcriptional regulation, the levels of RNA encoding C/EBPα and PU.1 were abnormally high in mutant B cell progenitors. Our findings indicate that the Gon4l protein is required for B lymphopoiesis and may function to regulate gene expression during this process.
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Affiliation(s)
- Ping Lu
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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23
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Beckers J, Wurst W, de Angelis MH. Towards better mouse models: enhanced genotypes, systemic phenotyping and envirotype modelling. Nat Rev Genet 2010; 10:371-80. [PMID: 19434078 DOI: 10.1038/nrg2578] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The mouse is the leading mammalian model organism for basic genetic research and for studying human diseases. Coordinated international projects are currently in progress to generate a comprehensive map of mouse gene functions - the first for any mammalian genome. There are still many challenges ahead to maximize the value of the mouse as a model, particularly for human disease. These involve generating mice that are better models of human diseases at the genotypic level, systemic (assessing all organ systems) and systematic (analysing all mouse lines) phenotyping of existing and new mouse mutant resources, and assessing the effects of the environment on phenotypes.
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Affiliation(s)
- Johannes Beckers
- Institute of Experimental Genetics, Helmholtz Zentrum München, GmbH, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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24
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Brown SDM, Wurst W, Kühn R, Hancock JM. The functional annotation of mammalian genomes: the challenge of phenotyping. Annu Rev Genet 2009; 43:305-33. [PMID: 19689210 DOI: 10.1146/annurev-genet-102108-134143] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mouse is central to the goal of establishing a comprehensive functional annotation of the mammalian genome that will help elucidate various human disease genes and pathways. The mouse offers a unique combination of attributes, including an extensive genetic toolkit that underpins the creation and analysis of models of human disease. An international effort to generate mutations for every gene in the mouse genome is a first and essential step in this endeavor. However, the greater challenge will be the determination of the phenotype of every mutant. Large-scale phenotyping for genome-wide functional annotation presents numerous scientific, infrastructural, logistical, and informatics challenges. These include the use of standardized approaches to phenotyping procedures for the population of unified databases with comparable data sets. The ultimate goal is a comprehensive database of molecular interventions that allows us to create a framework for biological systems analysis in the mouse on which human biology and disease networks can be revealed.
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Affiliation(s)
- Steve D M Brown
- MRC Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire OX11 0RD, United Kingdom.
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25
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Gondo Y, Fukumura R, Murata T, Makino S. Next-generation gene targeting in the mouse for functional genomics. BMB Rep 2009; 42:315-23. [PMID: 19558788 DOI: 10.5483/bmbrep.2009.42.6.315] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to elucidate ultimate biological function of the genome, the model animal system carrying mutations is indispensable. Recently, large-scale mutagenesis projects have been launched in various species. Especially, the mouse is considered to be an ideal model to human because it is a mammalian species accompanied with well-established genetic as well as embryonic technologies. In 1990's, large-scale mouse mutagenesis projects firstly initiated with a potent chemical mutagen, N-ethyl-N-nitrosourea (ENU) by the phenotype-driven approach or forward genetics. The knockout mouse mutagenesis projects with trapping/conditional mutagenesis have then followed as Phase II since 2006 by the gene-driven approach or reverse genetics. Recently, the next-generation gene targeting system has also become available to the research community, which allows us to establish and analyze mutant mice carrying an allelic series of base substitutions in target genes as another reverse genetics. Overall trends in the large-scale mouse mutagenesis will be reviewed in this article particularly focusing on the new advancement of the next-generation gene targeting system. The drastic expansion of the mutant mouse resources altogether will enhance the systematic understanding of the life. The construction of the mutant mouse resources developed by the forward and reverse genetic mutagenesis is just the beginning of the annotation of mammalian genome. They provide basic infrastructure to understand the molecular mechanism of the gene and genome and will contribute to not only basic researches but also applied sciences such as human disease modelling, genomic medicine and personalized medicine.
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Affiliation(s)
- Yoichi Gondo
- Mutagenesis and Genomics Team, RIKEN BioResource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
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26
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Dll1 haploinsufficiency in adult mice leads to a complex phenotype affecting metabolic and immunological processes. PLoS One 2009; 4:e6054. [PMID: 19562077 PMCID: PMC2699037 DOI: 10.1371/journal.pone.0006054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/26/2009] [Indexed: 11/19/2022] Open
Abstract
Background The Notch signaling pathway is an evolutionary conserved signal transduction pathway involved in embryonic patterning and regulation of cell fates during development and self-renewal. Recent studies have demonstrated that this pathway is integral to a complex system of interactions, involving as well other signal transduction pathways, and implicated in distinct human diseases. Delta-like 1 (Dll1) is one of the known ligands of the Notch receptors. The role of the Notch ligands is less well understood. Loss-of-function of Dll1 leads to embryonic lethality, but reduction of Delta-like 1 protein levels has not been studied in adult stage. Methodology/Principal Findings Here we present the haploinsufficient phenotype of Dll1 and a missense mutant Dll1 allele (Dll1C413Y). Haploinsufficiency leads to a complex phenotype with several biological processes altered. These alterations reveal the importance of Dll1 mainly in metabolism, energy balance and in immunology. The animals are smaller, lighter, with altered fat to lean ratio and have increased blood pressure and a slight bradycardia. The animals have reduced cholesterol and triglyceride levels in blood. At the immunological level a subtle phenotype is observed due to the effect and fine-tuning of the signaling network at the different levels of differentiation, proliferation and function of lymphocytes. Moreover, the importance of the proteolytic regulation of the Notch signaling network emphasized. Conclusions/Significance In conclusion, slight alterations in one player of Notch signaling alter the entire organism, emphasizing the fine-tuning character of this pathway in a high number of processes.
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27
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ENU-induced mutant mice for a next-generation gene-targeting system. PROGRESS IN BRAIN RESEARCH 2009. [PMID: 20302815 DOI: 10.1016/s0079-6123(09)17904-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
By the N-ethyl-N-nitrosourea (ENU)-based gene-driven mutagenesis, it is now possible to obtain allelic series of mutant mouse strains, each of which carries a different base substitution in any target gene. This new reverse genetic tool has become available based on the ENU mutant mouse library. The ENU mutant mouse library consists of dual archives of frozen sperm and corresponding genomic DNA derived from Generation-1 (G1) male mice, each of which carries thousands of ENU-induced base substitutions. Firstly, ENU-induced mutations in the target gene are screened from the genomic DNA archive by using one of the high-throughput mutation discovery systems. The identified mutations are then revived as live mice by the in vitro fertilization (IVF) and embryo transfer (ET) technology. Just like the knockout (KO) mouse system, the revived mutant strains are finally subjected to the three-generation scheme to reveal the gene function(s) of the target gene. This new reverse genetics or "next-generation gene-targeting system" allows us to elucidate the biological roles of the mouse genome in terms of single base-pair effects not only for the protein-coding sequences but also for any genomic sequences.
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28
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Acevedo-Arozena A, Wells S, Potter P, Kelly M, Cox RD, Brown SDM. ENU mutagenesis, a way forward to understand gene function. Annu Rev Genomics Hum Genet 2008; 9:49-69. [PMID: 18949851 DOI: 10.1146/annurev.genom.9.081307.164224] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Arguably, the main challenge for contemporary genetics is to understand the function of every gene in a mammalian genome. The mouse has emerged as a model for this task because its genome can be manipulated in a number of ways to study gene function or mimic disease states. Two complementary genetic approaches can be used to generate mouse models. A reverse genetics or gene-driven approach (gene to phenotype) starts from a known gene and manipulates the genome to create genetically modified mice, such as knockouts. Alternatively, a forward genetics or phenotype-driven approach (phenotype to gene) involves screening mice for mutant phenotypes without previous knowledge of the genetic basis of the mutation. N-ethyl-N-nitrosourea (ENU) mutagenesis has been widely used for both approaches to generate mouse mutants. Here we review progress in ENU mutagenesis screening, with an emphasis on creating mouse models for human disorders.
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29
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Cheng CH, Kikuchi T, Chen YH, Sabbagha NGAAA, Lee YC, Pan HJ, Chang C, Chen YT. Mutations in the SLC2A10 gene cause arterial abnormalities in mice. Cardiovasc Res 2008; 81:381-8. [DOI: 10.1093/cvr/cvn319] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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30
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Smith APL, Polley S, Wells S, Stewart M, Vizor L, Humphreys J, Warren MV, Dear N, Cheeseman MT. Analysis of breeding and pathology helps refine management practices of a large-scale N'-ethyl-N'-nitrosourea mouse mutagenesis programme. Lab Anim 2008; 43:1-10. [PMID: 18987059 DOI: 10.1258/la.2008.007072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
N'-ethyl-N'-nitrosourea (ENU) is a powerful germline mutagen used in conjunction with phenotype-driven screens to generate novel mouse mutants. ENU also induces genetic lesions in somatic cells and dosage requires optimization between maximum germline mutation rate versus induced sterility and tumourigenesis that compromise the welfare and fecundity of the ENU-treated males. Here, we present our experience with BALB/cAnNCrl and C57BL/6J mice in terms of the pathology induced by ENU and its impact on breeding. In both mouse strains, morbidity and mortality rises with ENU dose. In more than 75% of C57BL/6J males, morbidity and mortality were attributable to the development of malignant T-lymphoblastic lymphoma. Approximately 50% of ENU-treated BALB/cAnNCrl males develop early malignant T-lymphoblastic lymphoma, but the cohort that survives develops late-onset lung carcinoma. Within strains, the latency of these clinically important tumour(s) was not dosage-dependent, but the proportion of mice developing tumours and consequently removed from the breeding programme increased with ENU dosage. The median number of offspring per ENU-treated C57BL/6J male in standard matings with C3H/HeH females decreased with increasing dosage. The two most important underlying causes for lower male fecundity were increased infertility in the highest dosage group and reduced numbers of litters born to the remaining fertile C57BL/6J males due to a higher incidence of morbidity. These findings have allowed us to refine breeding strategy. To maximize the number of offspring from each ENU-treated male, we now rotate productive males between two cages to expose them to more females. This optimizes the number of mutation carrying offspring while reducing the number of ENU-treated males that must be generated.
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Affiliation(s)
- A P L Smith
- Mary Lyon Centre, Medical Research Council, Harwell, Oxfordshire OX11 0RD, UK
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van Boxtel R, Toonen PW, Verheul M, van Roekel HS, Nijman IJ, Guryev V, Cuppen E. Improved generation of rat gene knockouts by target-selected mutagenesis in mismatch repair-deficient animals. BMC Genomics 2008; 9:460. [PMID: 18840264 PMCID: PMC2567347 DOI: 10.1186/1471-2164-9-460] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 10/07/2008] [Indexed: 01/15/2023] Open
Abstract
Background The laboratory rat (Rattus norvegicus) is one of the preferred model organisms in physiological and pharmacological research, although the availability of specific genetic models, especially gene knockouts, is limited. N-ethyl-N-nitrosourea (ENU)-driven target-selected mutagenesis is currently the most successful method in rats, although it is still very laborious and expensive. Results As ENU-induced DNA damage is normally recognized by the mismatch repair (MMR) system, we hypothesized that the effectiveness of the target-selected mutagenesis approach could be improved by using a MMR-deficient genetic background. Indeed, Msh6 knockout rats were found to be more sensitive to ENU treatment and the germ line mutation rate was boosted more than two-fold to 1 mutation per 585 kb. In addition, the molecular mutation spectrum was found to be changed in favor of generating knockout-type alleles by ~20%, resulting in an overall increase in efficiency of ~2.5 fold. The improved effectiveness was demonstrated by high throughput mutation discovery in 70 Mb of sequence in a set of only 310 mutant F1 rats. This resulted in the identification of 89 mutations of which four introduced a premature stopcodon and 64 resulted in amino acid changes. Conclusion Taken together, we show that the use of a MMR-deficient background considerably improves ENU-driven target-selected mutagenesis in the rat, thereby reducing animal use as well as screening costs. The use of a mismatch repair-deficient genetic background for improving mutagenesis and target-selected knockout efficiency is in principle applicable to any organism of interest.
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Affiliation(s)
- Ruben van Boxtel
- Hubrecht Institute for Developmental Biology and Stem Cell Research, Cancer Genomics Center, Royal Netherlands Academy of Sciences, Utrecht, The Netherlands.
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Gondo Y. Trends in large-scale mouse mutagenesis: from genetics to functional genomics. Nat Rev Genet 2008; 9:803-10. [DOI: 10.1038/nrg2431] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Callewaert B, Loeys B, Casteleyn C, Willaert A, Dewint P, De Backer J, Sedlmeier R, Simoens P, De Paepe A, Coucke P. Absence of arterial phenotype in mice with homozygousslc2A10missense substitutions. Genesis 2008; 46:385-9. [DOI: 10.1002/dvg.20409] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Dokmanovic-Chouinard M, Chung WK, Chevre JC, Watson E, Yonan J, Wiegand B, Bromberg Y, Wakae N, Wright CV, Overton J, Ghosh S, Sathe GM, Ammala CE, Brown KK, Ito R, LeDuc C, Solomon K, Fischer SG, Leibel RL. Positional cloning of "Lisch-Like", a candidate modifier of susceptibility to type 2 diabetes in mice. PLoS Genet 2008; 4:e1000137. [PMID: 18654634 PMCID: PMC2464733 DOI: 10.1371/journal.pgen.1000137] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 06/20/2008] [Indexed: 12/17/2022] Open
Abstract
In 404 Lepob/ob F2 progeny of a C57BL/6J (B6) x DBA/2J (DBA) intercross, we mapped a DBA-related quantitative trait locus (QTL) to distal Chr1 at 169.6 Mb, centered about D1Mit110, for diabetes-related phenotypes that included blood glucose, HbA1c, and pancreatic islet histology. The interval was refined to 1.8 Mb in a series of B6.DBA congenic/subcongenic lines also segregating for Lepob. The phenotypes of B6.DBA congenic mice include reduced β-cell replication rates accompanied by reduced β-cell mass, reduced insulin/glucose ratio in blood, reduced glucose tolerance, and persistent mild hypoinsulinemic hyperglycemia. Nucleotide sequence and expression analysis of 14 genes in this interval identified a predicted gene that we have designated “Lisch-like” (Ll) as the most likely candidate. The gene spans 62.7 kb on Chr1qH2.3, encoding a 10-exon, 646–amino acid polypeptide, homologous to Lsr on Chr7qB1 and to Ildr1 on Chr16qB3. The largest isoform of Ll is predicted to be a transmembrane molecule with an immunoglobulin-like extracellular domain and a serine/threonine-rich intracellular domain that contains a 14-3-3 binding domain. Morpholino knockdown of the zebrafish paralog of Ll resulted in a generalized delay in endodermal development in the gut region and dispersion of insulin-positive cells. Mice segregating for an ENU-induced null allele of Ll have phenotypes comparable to the B.D congenic lines. The human ortholog, C1orf32, is in the middle of a 30-Mb region of Chr1q23-25 that has been repeatedly associated with type 2 diabetes. Type 2 diabetes (T2D) accounts for over 90% of instances of diabetes and is a leading cause of medical morbidity and mortality. Twin studies indicate a strong polygenic contribution to susceptibility within the context of obesity. Although approximately ten genes making important contributions to individual risk have been identified, it is clear that others remain to be identified. In this study, we intercrossed obese, diabetes-resistant and diabetes-prone mouse strains to implicate a genetic interval on mouse Chr1 associated with reduced β-cell numbers and elevated blood glucose. We narrowed the region using molecular genetics and computational approaches to identify a novel gene we designated “Lisch-like” (Ll). The orthologous human genetic interval has been repeatedly implicated in T2D. Mice with an induced mutation that reduces Ll expression are impaired in both β-cell development and glucose metabolism, and reduced expression of the homologous gene in zebrafish disrupts islet development. Ll is expressed in organs implicated in the pathophysiology of T2D (hypothalamus, islets, liver, and skeletal muscle) and is predicted to encode a transmembrane protein that could mediate cholesterol transport and/or convey signals related to cell division. Either mechanism could mediate effects on β-cell mass that would predispose to T2D.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blood Glucose/genetics
- Chromosomes, Mammalian
- Cloning, Molecular
- Crosses, Genetic
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Type 2/genetics
- Genetic Predisposition to Disease
- Glucose Tolerance Test/methods
- Haplotypes
- Homozygote
- Insulin/blood
- Male
- Mice
- Mice, Congenic
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Obese
- Molecular Sequence Data
- Mutation
- Protein Isoforms/chemistry
- Protein Isoforms/genetics
- Quantitative Trait Loci
- Receptors, Cell Surface/genetics
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Affiliation(s)
| | - Wendy K. Chung
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Jean-Claude Chevre
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Elizabeth Watson
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Jason Yonan
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Beebe Wiegand
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Yana Bromberg
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Nao Wakae
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Chris V. Wright
- Vanderbilt University, Nashville, Tennessee, United States of America
| | - John Overton
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Sujoy Ghosh
- Clinical Pharmacology and Discovery Medicine, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America
| | - Ganesh M. Sathe
- Discovery Technology Group, GlaxoSmithKline Pharmaceuticals, Collegeville, Pennsylvania, United States of America
| | - Carina E. Ammala
- Center of Excellence for Drug Discovery, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America
| | - Kathleen K. Brown
- Center of Excellence for Drug Discovery, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America
| | - Rokuro Ito
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Charles LeDuc
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Keely Solomon
- Vanderbilt University, Nashville, Tennessee, United States of America
| | - Stuart G. Fischer
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
| | - Rudolph L. Leibel
- Naomi Berrie Diabetes Center, Columbia University, New York, New York, United States of America
- * E-mail:
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Grosse J, Braun A, Varga-Szabo D, Beyersdorf N, Schneider B, Zeitlmann L, Hanke P, Schropp P, Mühlstedt S, Zorn C, Huber M, Schmittwolf C, Jagla W, Yu P, Kerkau T, Schulze H, Nehls M, Nieswandt B. An EF hand mutation in Stim1 causes premature platelet activation and bleeding in mice. J Clin Invest 2008; 117:3540-50. [PMID: 17965774 DOI: 10.1172/jci32312] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 08/15/2007] [Indexed: 12/31/2022] Open
Abstract
Changes in cytoplasmic Ca2+ levels regulate a variety of fundamental cellular functions in virtually all cells. In nonexcitable cells, a major pathway of Ca2+ entry involves receptor-mediated depletion of intracellular Ca2+ stores followed by the activation of store-operated calcium channels in the plasma membrane. We have established a mouse line expressing an activating EF hand motif mutant of stromal interaction molecule 1 (Stim1), an ER receptor recently identified as the Ca2+ sensor responsible for activation of Ca2+ release-activated (CRAC) channels in T cells, whose function in mammalian physiology is not well understood. Mice expressing mutant Stim1 had macrothrombocytopenia and an associated bleeding disorder. Basal intracellular Ca2+ levels were increased in platelets, which resulted in a preactivation state, a selective unresponsiveness to immunoreceptor tyrosine activation motif-coupled agonists, and increased platelet consumption. In contrast, basal Ca2+ levels, but not receptor-mediated responses, were affected in mutant T cells. These findings identify Stim1 as a central regulator of platelet function and suggest a cell type-specific activation or composition of the CRAC complex.
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Aigner B, Rathkolb B, Herbach N, Hrabé de Angelis M, Wanke R, Wolf E. Diabetes models by screen for hyperglycemia in phenotype-driven ENU mouse mutagenesis projects. Am J Physiol Endocrinol Metab 2008; 294:E232-40. [PMID: 18056790 DOI: 10.1152/ajpendo.00592.2007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
More than 150 million people suffer from diabetes mellitus worldwide, and this number is expected to rise substantially within the next decades. Despite its high prevalence, the pathogenesis of diabetes mellitus is not completely understood. Therefore, appropriate experimental models are essential tools to gain more insight into the genetics and pathogenesis of the disease. Here, we describe the current efforts to establish novel diabetes models derived from unbiased, phenotype-driven, large-scale N-ethyl-N-nitrosourea (ENU) mouse mutagenesis projects started a decade ago using hyperglycemia as a high-throughput screen parameter. Mouse lines were established according to their hyperglycemia phenotype over several generations, thereby revealing a mutation as cause for the aberrant phenotype. Chromosomal assignment of the causative mutation and subsequent candidate gene analysis led to the detection of the mutations that resulted in novel alleles of genes already known to be involved in glucose homeostasis, like glucokinase, insulin 2, and insulin receptor. Additional ENU-induced hyperglycemia lines are under genetic analysis. Improvements in screen for diabetic animals are implemented to detect more subtle phenotypes. Moreover, diet challenge assays are being employed to uncover interactions between genetic and environmental factors in the pathogenesis of diabetes mellitus. The new mouse mutants recovered in phenotype-driven ENU mouse mutagenesis projects complement the available models generated by targeted mutagenesis of candidate genes, all together providing the large resource of models required for a systematic dissection of the pathogenesis of diabetes mellitus.
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Affiliation(s)
- Bernhard Aigner
- Institute of Molecular Animal Breeding and Biotechnology, Hackerstrasse 27, Oberschleissheim, Germany.
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37
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Dobler T, Springauf A, Tovornik S, Weber M, Schmitt A, Sedlmeier R, Wischmeyer E, Döring F. TRESK two-pore-domain K+ channels constitute a significant component of background potassium currents in murine dorsal root ganglion neurones. J Physiol 2007; 585:867-79. [PMID: 17962323 PMCID: PMC2375503 DOI: 10.1113/jphysiol.2007.145649] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/27/2007] [Accepted: 10/22/2007] [Indexed: 12/13/2022] Open
Abstract
TRESK (TWIK-related spinal cord K(+) channel) is the most recently identified member of the two-pore-domain potassium channel (K(2P)) family, the molecular source of background potassium currents. Human TRESK channels are not affected by external acidification. However, the mouse orthologue displays moderate pH dependence isolated to a single histidine residue adjacent to the GYG selectivity filter. In the human protein, sequence substitution of tyrosine by histidine at this critical position generated a mutant that displays almost identical proton sensitivity compared with mouse TRESK. In contrast to human TRESK, which is specifically located in spinal cord, we detected mouse TRESK (mTRESK) mRNA in several epithelial and neuronal tissues including lung, liver, kidney, brain and spinal cord. As revealed by endpoint and quantitative RT-PCR, mTRESK channels are mainly expressed in dorsal root ganglia (DRG) and on the transcript level represent the most important background potassium channel in this tissue. DRG neurones of all sizes were labelled by in situ hybridizations with TRESK-specific probes. In DRG neurones of TRESK[G339R] functional knock-out (KO) mice the standing outward current IK(so) was significantly reduced compared with TRESK wild-type (WT) littermates. Different responses to K(2P) channel regulators such as bupivacaine, extracellular protons and quinidine corroborated the finding that approximately 20% of IK(so) is carried by TRESK channels. Unexpectedly, we found no difference in resting membrane potential between DRG neurones of TRESK[WT] and TRESK[G339R] functional KO mice. However, in current-clamp recordings we observed significant changes in action potential duration and amplitude of after-hyperpolarization. Most strikingly, cellular excitability of DRG neurones from functional KO mice was significantly augmented as revealed by reduced rheobase current to elicit action potentials.
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Affiliation(s)
- Tina Dobler
- Institute of Physiology, University of Würzburg, Röntgenring 9, 97070 Würzburg, Germany
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38
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Schneider B, Koppius A, Sedlmeier R. Use of an exon-trapping vector for the evaluation of splice-site mutations. Mamm Genome 2007; 18:670-6. [PMID: 17687606 DOI: 10.1007/s00335-007-9047-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Accepted: 06/07/2007] [Indexed: 10/23/2022]
Abstract
Prediction of the effects of splice-site variations by sequence analysis is difficult. In this study we provide the means for a rapid evaluation of the potential for splice-site mutations to interfere with RNA processing. The system may be useful in reverse genetics or mapping studies when isolation and characterization of mRNA is arduous or not possible. In the assay we cloned wild-type and mutant sequences of murine splice-site mutations into an exon-trapping vector and characterized splicing of both recombinant transcripts in a transient cell culture system. Results from this artificial assay were compared with in vivo data from the respective mouse models. We found that the exon-trapping system allows one to confidently predict whether a splice-site variation is going to have a splicing effect in vivo, but the system does not always reflect in vivo splicing in detail. In summary, the exon-trapping system is a reliable and easy-to-use tool for a first evaluation of splice effects.
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Affiliation(s)
- Boris Schneider
- Ingenium Pharmaceuticals AG, Fraunhoferstr 13, 82152, Martinsried, Germany
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39
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Mutational pattern and frequency of induced nucleotide changes in mouse ENU mutagenesis. BMC Mol Biol 2007; 8:52. [PMID: 17584492 PMCID: PMC1914352 DOI: 10.1186/1471-2199-8-52] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 06/20/2007] [Indexed: 11/16/2022] Open
Abstract
Background With the advent of sequence-based approaches in the mutagenesis studies, it is now possible to directly evaluate the genome-wide pattern of experimentally induced DNA sequence changes for a diverse array of organisms. To gain a more comprehensive understanding of the mutational bias inherent in mouse ENU mutagenesis, this study describes a detailed evaluation of the induced mutational pattern obtained from a sequence-based screen of ENU-mutagenized mice. Results Based on a large-scale screening data, we derive the sequence-based estimates of the nucleotide-specific pattern and frequency of ENU-induced base replacement mutation in the mouse germline, which are then combined with the pattern of codon usage in the mouse coding sequences to infer the spectrum of amino acid changes obtained by ENU mutagenesis. We detect a statistically significant difference between the mutational patterns in phenotype- versus sequence-based screens, which presumably reflects differential phenotypic effects caused by different amino acid replacements. We also demonstrate that the mutations exhibit strong strand asymmetry, and that this imbalance is generated by transcription, most likely as a by-product of transcription-coupled DNA repair in the germline. Conclusion The results clearly illustrate the biased nature of ENU-induced mutations. We expect that a precise understanding of the mutational pattern and frequency of induced nucleotide changes would be of practical importance when designing sequence-based screening strategies to generate mutant mouse strains harboring amino acid variants at specific loci. More generally, by enhancing the collection of experimentally induced mutations in unambiguously defined genomic regions, sequence-based mutagenesis studies will further illuminate the molecular basis of mutagenic and repair mechanisms that preferentially produce a certain class of mutational changes over others.
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40
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Oliver PL, Bitoun E, Davies KE. Comparative genetic analysis: the utility of mouse genetic systems for studying human monogenic disease. Mamm Genome 2007; 18:412-24. [PMID: 17514509 PMCID: PMC1998876 DOI: 10.1007/s00335-007-9014-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 03/19/2007] [Accepted: 03/22/2007] [Indexed: 12/23/2022]
Abstract
One of the long-term goals of mutagenesis programs in the mouse has been to generate mutant lines to facilitate the functional study of every mammalian gene. With a combination of complementary genetic approaches and advances in technology, this aim is slowly becoming a reality. One of the most important features of this strategy is the ability to identify and compare a number of mutations in the same gene, an allelic series. With the advent of gene-driven screening of mutant archives, the search for a specific series of interest is now a practical option. This review focuses on the analysis of multiple mutations from chemical mutagenesis projects in a wide variety of genes and the valuable functional information that has been obtained from these studies. Although gene knockouts and transgenics will continue to be an important resource to ascertain gene function, with a significant proportion of human diseases caused by point mutations, identifying an allelic series is becoming an equally efficient route to generating clinically relevant and functionally important mouse models.
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Affiliation(s)
- Peter L. Oliver
- Department of Physiology, Anatomy and Genetics, MRC Functional Genetics Unit, University of Oxford, South Parks Road, Oxford, OX1 3QX UK
| | - Emmanuelle Bitoun
- Department of Physiology, Anatomy and Genetics, MRC Functional Genetics Unit, University of Oxford, South Parks Road, Oxford, OX1 3QX UK
| | - Kay E. Davies
- Department of Physiology, Anatomy and Genetics, MRC Functional Genetics Unit, University of Oxford, South Parks Road, Oxford, OX1 3QX UK
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Davies VJ, Hollins AJ, Piechota MJ, Yip W, Davies JR, White KE, Nicols PP, Boulton ME, Votruba M. Opa1 deficiency in a mouse model of autosomal dominant optic atrophy impairs mitochondrial morphology, optic nerve structure and visual function. Hum Mol Genet 2007; 16:1307-18. [PMID: 17428816 DOI: 10.1093/hmg/ddm079] [Citation(s) in RCA: 307] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
OPA1 is a ubiquitously expressed, nuclear dynamin-related GTPase, targeted to the inner mitochondrial membrane, which plays a role in mitochondrial fusion. Mutations in the OPA1 gene on chromosome 3q28-qter are associated with autosomal dominant optic atrophy (ADOA), the most common inherited optic neuropathy, in which retinal ganglion cells (RGCs) are lost and visual acuity is impaired from an early age. We have generated a novel ENU-induced mutant mouse carrying a protein-truncating nonsense mutation in opa1 in order to explore the pathophysiology of ADOA. The heterozygous mutation, B6; C3-Opa1(Q285STOP), located in exon 8 immediately before the central dynamin-GTPase, leads to approximately 50% reduction in opa1 protein in retina and all tissues on western analysis. The homozygous mutation is embryonic lethal by 13.5 days post coitum, demonstrating the importance of Opa1 during early development. Fibroblasts taken from adult heterozygous mutant mice show an apparent alteration in morphology, with an increase in mitochondrial fission and fragmentation. Heterozygous mutants show a slow onset of degeneration in the optic nerve electron microscopy. Furthermore, they demonstrate a functional reduction in visual function on testing with the optokinetic drum and the circadian running wheel. These findings indicate that the opa1 GTPase contains crucial information required for the survival of RGCs and that Opa1 is essential for early embryonic survival. The Opa1 +/- mice described here provide a means to directly investigate the cellular pathophysiology of OPA1 ADOA.
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Affiliation(s)
- Vanessa J Davies
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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42
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Barbaric I, Wells S, Russ A, Dear TN. Spectrum of ENU-induced mutations in phenotype-driven and gene-driven screens in the mouse. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2007; 48:124-42. [PMID: 17295309 DOI: 10.1002/em.20286] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
N-ethyl-N-nitrosourea (ENU) mutagenesis in mice has become a standard tool for (i) increasing the pool of mutants in many areas of biology, (ii) identifying novel genes involved in physiological processes and disease, and (iii) in assisting in assigning functions to genes. ENU is assumed to cause random mutations throughout the mouse genome, but this presumption has never been analyzed. This is a crucial point, especially for large-scale mutagenesis, as a bias would reflect a constraint on identifying possible genetic targets. There is a significant body of published data now available from both phenotype-driven and gene-driven ENU mutagenesis screens in the mouse that can be used to reveal the effectiveness and limitations of an ENU mutagenesis approach. Analysis of the published data is presented in this paper. As expected for a randomly acting mutagen, ENU-induced mutations identified in phenotype-driven screens were in genes that had higher coding sequence length and higher exon number than the average for the mouse genome. Unexpectedly, the data showed that ENU-induced mutations were more likely to be found in genes that had a higher G + C content and neighboring base analysis revealed that the identified ENU mutations were more often directly flanked by G or C nucleotides. ENU mutations from phenotype-driven and gene-driven screens were dominantly A:T to T:A transversions or A:T to G:C transitions. Knowledge of the spectrum of mutations that ENU elicits will assist in positional cloning of ENU-induced mutations by allowing prioritization of candidate genes based on some of their inherent features.
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Affiliation(s)
- Ivana Barbaric
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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Rhodes JS, Ford MM, Yu CH, Brown LL, Finn DA, Garland T, Crabbe JC. Mouse inbred strain differences in ethanol drinking to intoxication. GENES BRAIN AND BEHAVIOR 2007; 6:1-18. [PMID: 17233637 DOI: 10.1111/j.1601-183x.2006.00210.x] [Citation(s) in RCA: 272] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recently, we described a simple procedure, Drinking in the Dark (DID), in which C57BL/6J mice self-administer ethanol to a blood ethanol concentration (BEC) above 1 mg/ml. The test consists of replacing the water with 20% ethanol in the home cage for 4 h early during the dark phase of the light/dark cycle. Three experiments were conducted to explore this high ethanol drinking model further. In experiment 1, a microanalysis of C57BL/6J behavior showed that the pattern of ethanol drinking was different from routine water intake. In experiment 2, drinking impaired performance of C57BL/6J on the accelerating rotarod and balance beam. In experiment 3, 12 inbred strains were screened to estimate genetic influences on DID and correlations with other traits. Large, reliable differences in intake and BEC were detected among the strains, with C57BL/6J showing the highest values. Strain means were positively correlated with intake and BEC in the standard (24 h) and a limited (4 h) two-bottle ethanol vs. water test, but BECs reached higher levels for DID. Strain mean correlations with other traits in the Mouse Phenome Project database supported previously reported genetic relationships of high ethanol drinking with low chronic ethanol withdrawal severity and low ethanol-conditioned taste aversion. We extend these findings by showing that the correlation estimates remain relatively unchanged even after correcting for phylogenetic relatedness among the strains, thus relaxing the assumption that the strain means are statistically independent. We discuss applications of the model for finding genes that predispose pharmacologically significant drinking in mice.
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Affiliation(s)
- J S Rhodes
- Department of Psychology, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
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44
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Silver JD, Hilton DJ, Bahlo M, Kile BT. Probabilistic analysis of recessive mutagenesis screen strategies. Mamm Genome 2007; 18:5-22. [PMID: 17245609 DOI: 10.1007/s00335-006-0057-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Accepted: 09/15/2006] [Indexed: 11/27/2022]
Abstract
Random mutagenesis screens for recessive phenotypes require three generations of breeding, using either a backcross (BC) or intercross (IC) strategy. Hence, they are more costly and technically demanding than those for dominant phenotypes. Maximizing the return from these screens requires maximizing the number of mutations that are bred to homozyosity in the G(3) generation. Using a probabilistic approach, we compare different designs of screens for recessive phenotypes and the impact each one has on the number of mutations that can be effectively screened. We address the issue of BC versus IC strategies and consider genome-wide, region-specific screens and suppressor screens. We find that optimally designed BC and IC screens allow the screening of, on average, similar numbers of mutations but that interpedigree variation is more pronounced when the IC strategy is employed. By conducting a retrospective analysis of published mutagenesis screens, we show that, depending on the strategy, a threefold difference in the numbers of mutations screened per animal used could be expected. This method allows researchers to contrast, for a range of experimental designs, the cost per mutation screened and to maximize the number of mutations that one can expect to screen in a given experiment.
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Affiliation(s)
- Jeremy D Silver
- Division of Molecular Medicine and the Division of Bioinformatics, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
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Rudelius M, Osanger A, Kohlmann S, Augustin M, Piontek G, Heinzmann U, Jennen G, Russ A, Matiasek K, Stumm G, Schlegel J. A missense mutation in the WD40 domain of murine Lyst is linked to severe progressive Purkinje cell degeneration. Acta Neuropathol 2006; 112:267-76. [PMID: 16791600 DOI: 10.1007/s00401-006-0092-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2006] [Revised: 05/22/2006] [Accepted: 05/23/2006] [Indexed: 11/29/2022]
Abstract
Disturbance of intracellular trafficking plays a major role in several neurodegenerative disorders including Alzheimer or Parkinson's disease. The Chediak-Higashi syndrome (CHS), a life-threatening autosomal recessive disease with frequent mutations in the LYST gene, and its animal model, the beige mouse, are both characterized by lysosomal defects with accumulation of giant lysosomes. Clinically they manifest as hypopigmentation, abnormal bleeding and increased susceptibility to infection with various degrees of involvement of the nervous system. In the course of a recessive N-ethyl-N-nitrosurea (ENU) mutagenesis screen, we identified the first murine missense mutation in the lysosomal trafficking regulator gene (Lyst(Ing3618)) located at a highly conserved position in the WD40 protein domain. Nearly all described human Lyst alleles lead to protein truncation and fatal childhood CHS. Only four different missense mutations have been reported in patients with adolescent or adult forms of CHS involving the nervous system. Interestingly, the Lyst(Ing3618) model presents with a predominant neurodegenerative phenotype with progressive degeneration and loss of Purkinje cells and lacks severe impairment of the immune system. Therefore, the Lyst(Ing3618 )allele could represent a new model for adult CHS with neurological impairment. It could also provide an important tool to elucidate the role of neuronal lysosomal trafficking in the pathophysiology of neurodegeneration.
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Affiliation(s)
- Martina Rudelius
- Division of Neuropathology, Institute of Pathology, Technical University of Munich, Ismaninger Strasse 22, 81675 Munich, Germany
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Cook MC, Vinuesa CG, Goodnow CC. ENU-mutagenesis: insight into immune function and pathology. Curr Opin Immunol 2006; 18:627-33. [PMID: 16889948 DOI: 10.1016/j.coi.2006.07.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Accepted: 07/20/2006] [Indexed: 12/25/2022]
Abstract
In random chemical mutagenesis, gene discovery is driven by phenotypes rather than by hypotheses. A standard dose of N-ethyl-N-nitrosourea results in approximately 30 coding mutations in male G1 mice, of which approximately 4 can be propagated to homozygosity in 3 generations. In recent years, large-scale screens of such G3 mice for phenotypes of interest to immunologists have revealed clues to the number of genes responsible for key immune responses, such as innate recognition of pathogens and autoantibody production. More than 20 of the phenotypes that exhibit a simple (Mendelian) pattern of inheritance have been mapped. Novel alleles have revealed new pathways of host defense, allergy and autoimmunity.
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Affiliation(s)
- Matthew C Cook
- Frank Fenner Building, Australian National University, Canberra ACT 0200, Australia.
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Reue K, Vergnes L. Approaches to lipid metabolism gene identification and characterization in the postgenomic era. J Lipid Res 2006; 47:1891-907. [PMID: 16835441 DOI: 10.1194/jlr.r600020-jlr200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The availability of genomic resources has already had a tremendous impact on biomedical research. In this review, we describe how whole genome sequence and high-throughput functional genomics projects have facilitated the identification and characterization of important genes in lipid metabolism and disease. We review key approaches and lipid genes identified in the first years of this century and discuss how genomic resources are likely to streamline gene identification and functional characterization in the future.
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Affiliation(s)
- Karen Reue
- Department of Human Genetics and Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
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Grosse J, Tarnow P, Römpler H, Schneider B, Sedlmeier R, Huffstadt U, Korthaus D, Nehls M, Wattler S, Schöneberg T, Biebermann H, Augustin M. N-ethyl-N-nitrosourea-based generation of mouse models for mutant G protein-coupled receptors. Physiol Genomics 2006; 26:209-17. [PMID: 16720677 DOI: 10.1152/physiolgenomics.00289.2005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chemical random mutagenesis techniques with the germ line supermutagen N-ethyl-N-nitrosourea (ENU) have been established to provide comprehensive collections of mouse models, which were then mined and analyzed in phenotype-driven studies. Here, we applied ENU mutagenesis in a high-throughput fashion for a gene-driven identification of new mutations. Selected members of the large superfamily of G protein-coupled receptors (GPCR), melanocortin type 3 (Mc3r) and type 4 (Mc4r) receptors, and the orphan chemoattractant receptor GPR33, were used as model targets to prove the feasibility of this approach. Parallel archives of DNA and sperm from mice mutagenized with ENU were screened for mutations in these GPCR, and in vitro assays served as a preselection step before in vitro fertilization was performed to generate the appropriate mouse model. For example, mouse models for inherited obesity were established by selecting fully or partially inactivating mutations in Mc4r. Our technology described herein has the potential to provide mouse models for a GPCR dysfunction of choice within <4 mo and can be extended to other gene classes of interest.
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MESH Headings
- Alkylating Agents/toxicity
- Animals
- COS Cells
- Chlorocebus aethiops
- DNA Mutational Analysis/methods
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Ethylnitrosourea/toxicity
- Female
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mutagenesis/drug effects
- Mutation/genetics
- Phylogeny
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/physiology
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/physiology
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Signal Transduction/physiology
- Transfection
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Grosse J, Chitu V, Marquardt A, Hanke P, Schmittwolf C, Zeitlmann L, Schropp P, Barth B, Yu P, Paffenholz R, Stumm G, Nehls M, Stanley ER. Mutation of mouse Mayp/Pstpip2 causes a macrophage autoinflammatory disease. Blood 2006; 107:3350-8. [PMID: 16397132 PMCID: PMC1895761 DOI: 10.1182/blood-2005-09-3556] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Accepted: 11/30/2005] [Indexed: 02/02/2023] Open
Abstract
Macrophage actin-associated tyrosine phosphorylated protein (MAYP)/PSTPIP2, a PCH protein, is involved in the regulation of macrophage motility. Mutations in a closely related gene, PSTPIP1/CD2BP1, cause a dominantly inherited autoinflammatory disorder known as PAPA syndrome. A mutant mouse obtained by chemical mutagenesis exhibited an autoinflammatory disorder characterized by macrophage infiltration and inflammation, leading to osteolysis and necrosis in paws and necrosis of ears. Positional cloning of this recessive mutation, termed Lupo, identified a T to A nucleotide exchange leading to an amino acid substitution (I282N) in the sequence of MAYP. Mayp(Lp/Lp) disease was transferable by bone marrow transplantation and developed in the absence of lymphocytes. Consistent with the involvement of macrophages, lesion development could be prevented by the administration of clodronate liposomes. MAYP is expressed in monocytes/macrophages and in a Mac1+ subfraction of granulocytes. LPS stimulation increases its expression in macrophages. Because of the instability of the mutant protein, MAYP expression is reduced 3-fold in Mayp(Lp/Lp) macrophages and, on LPS stimulation, does not rise above the level of unstimulated wild-type (WT) cells. Mayp(Lp/Lp) mice expressed elevated circulating levels of several cytokines, including MCP-1; their macrophages exhibited altered cytokine production in vitro. These studies suggest that MAYP plays an anti-inflammatory role in macrophages.
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Abstract
The house mouse has been used as a privileged model organism since the early days of genetics, and the numerous experiments made with this small mammal have regularly contributed to enrich our knowledge of mammalian biology and pathology, ranging from embryonic development to metabolic disease, histocompatibility, immunology, behavior, and cancer. Over the past two decades, a number of large-scale integrated and concerted projects have been undertaken that will probably open a new era in the genetics of the species. The sequencing of the genome, which will allow researchers to make comparisons with other mammals and identify regions conserved by evolution, is probably the most important project, but many other initiatives, such as the massive production of point or chromosomal mutations associated with comprehensive and standardized phenotyping of the mutant phenotypes, will help annotation of the approximately 25,000 genes packed in the mouse genome. In the same way, and as another consequence of the sequencing, the discovery of many single nucleotide polymorphisms and the development of new tools and resources, like the Collaborative Cross, will contribute to the development of modern quantitative genetics. It is clear that mouse genetics has changed dramatically over the last 10-15 years and its future looks promising.
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Affiliation(s)
- Jean Louis Guénet
- Département de Biologie du Développement, Institut Pasteur, 75724 Paris Cedex 15, France.
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