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Sheardown E, Mech AM, Petrazzini MEM, Leggieri A, Gidziela A, Hosseinian S, Sealy IM, Torres-Perez JV, Busch-Nentwich EM, Malanchini M, Brennan CH. Translational relevance of forward genetic screens in animal models for the study of psychiatric disease. Neurosci Biobehav Rev 2022; 135:104559. [PMID: 35124155 PMCID: PMC9016269 DOI: 10.1016/j.neubiorev.2022.104559] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 12/10/2021] [Accepted: 02/01/2022] [Indexed: 12/16/2022]
Abstract
Psychiatric disorders represent a significant burden in our societies. Despite the convincing evidence pointing at gene and gene-environment interaction contributions, the role of genetics in the etiology of psychiatric disease is still poorly understood. Forward genetic screens in animal models have helped elucidate causal links. Here we discuss the application of mutagenesis-based forward genetic approaches in common animal model species: two invertebrates, nematodes (Caenorhabditis elegans) and fruit flies (Drosophila sp.); and two vertebrates, zebrafish (Danio rerio) and mice (Mus musculus), in relation to psychiatric disease. We also discuss the use of large scale genomic studies in human populations. Despite the advances using data from human populations, animal models coupled with next-generation sequencing strategies are still needed. Although with its own limitations, zebrafish possess characteristics that make them especially well-suited to forward genetic studies exploring the etiology of psychiatric disorders.
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Affiliation(s)
- Eva Sheardown
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Aleksandra M Mech
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | | | - Adele Leggieri
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Agnieszka Gidziela
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Saeedeh Hosseinian
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Ian M Sealy
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK
| | - Jose V Torres-Perez
- UK Dementia Research Institute at Imperial College London and Department of Brain Sciences, Imperial College London, 86 Wood Lane, London W12 0BZ, UK
| | - Elisabeth M Busch-Nentwich
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Margherita Malanchini
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Caroline H Brennan
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK.
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2
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Li C, Zheng Z, Zhang X, Asatrian G, Chen E, Song R, Culiat C, Ting K, Soo C. Nfatc1 Is a Functional Transcriptional Factor Mediating Nell-1-Induced Runx3 Upregulation in Chondrocytes. Int J Mol Sci 2018; 19:ijms19010168. [PMID: 29316655 PMCID: PMC5796117 DOI: 10.3390/ijms19010168] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 12/19/2017] [Accepted: 01/05/2018] [Indexed: 01/01/2023] Open
Abstract
Neural EGFL like 1 (Nell-1) is essential for chondrogenic differentiation, maturation, and regeneration. Our previous studies have demonstrated that Nell-1's pro-chondrogenic activities are predominantly reliant upon runt-related transcription factor 3 (Runx3)-mediated Indian hedgehog (Ihh) signaling. Here, we identify the nuclear factor of activated T-cells 1 (Nfatc1) as the key transcriptional factor mediating the Nell-1 → Runx3 signal transduction in chondrocytes. Using chromatin immunoprecipitation assay, we were able to determine that Nfatc1 binds to the -833--810 region of the Runx3-promoter in response to Nell-1 treatment. By revealing the Nell-1 → Nfatc1 → Runx3 → Ihh cascade, we demonstrate the involvement of Nfatc1, a nuclear factor of activated T-cells, in chondrogenesis, while providing innovative insights into developing a novel therapeutic strategy for cartilage regeneration and other chondrogenesis-related conditions.
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Affiliation(s)
- Chenshuang Li
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Zhong Zheng
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Xinli Zhang
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Greg Asatrian
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Eric Chen
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Richard Song
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Cymbeline Culiat
- NellOne Therapeutics, Inc., 99 Midway Ln # E, Oak Ridge, TN 37830, USA.
| | - Kang Ting
- Division of Growth and Development, Section of Orthodontics, School of Dentistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Chia Soo
- Division of Plastic and Reconstructive Surgery and Department of Orthopaedic Surgery, the Orthopaedic Hospital Research Center, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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Li C, Jiang J, Zheng Z, Lee KS, Zhou Y, Chen E, Culiat CT, Qiao Y, Chen X, Ting K, Zhang X, Soo C. Neural EGFL-Like 1 Is a Downstream Regulator of Runt-Related Transcription Factor 2 in Chondrogenic Differentiation and Maturation. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:963-972. [PMID: 28302495 PMCID: PMC5417045 DOI: 10.1016/j.ajpath.2016.12.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/21/2016] [Accepted: 12/22/2016] [Indexed: 10/20/2022]
Abstract
Recent studies indicate that neural EGFL-like 1 (Nell-1), a secretive extracellular matrix molecule, is involved in chondrogenic differentiation. Herein, we demonstrated that Nell-1 serves as a key downstream target of runt-related transcription factor 2 (Runx2), a central regulator of chondrogenesis. Unlike in osteoblast lineage cells where Nell-1 and Runx2 demonstrate mutual regulation, further studies in chondrocytes revealed that Runx2 tightly regulates the expression of Nell-1; however, Nell-1 does not alter the expression of Runx2. More important, Nell-1 administration partially restored Runx2 deficiency-induced impairment of chondrocyte differentiation and maturation in vitro, ex vivo, and in vivo. Mechanistically, although the expression of Nell-1 is highly reliant on Runx2, the prochondrogenic function of Nell-1 persisted in Runx2-/- scenarios. The biopotency of Nell-1 is independent of the nuclear import and DNA binding functions of Runx2 during chondrogenesis. Nell-1 is a key functional mediator of chondrogenesis, thus opening up new possibilities for the application of Nell-1 in cartilage regeneration.
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Affiliation(s)
- Chenshuang Li
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California; Department of Orthodontics, Peking University, School and Hospital of Stomatology, Beijing, China
| | - Jie Jiang
- UCLA Division of Plastic and Reconstructive Surgery, Department of Orthopaedic Surgery, Orthopaedic Hospital Research Center, University of California, Los Angeles, Los Angeles, California
| | - Zhong Zheng
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California
| | - Kevin S Lee
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California
| | - Yanheng Zhou
- Department of Orthodontics, Peking University, School and Hospital of Stomatology, Beijing, China
| | - Eric Chen
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California
| | | | - Yiqiang Qiao
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California; Department of Orthodontics, School of Stomatology, Zhengzhou University, Zhengzhou, China
| | - Xuepeng Chen
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California; Department of Orthodontics, Hospital of Stomatology, Zhejiang University, Hangzhou, China
| | - Kang Ting
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California; UCLA Division of Plastic and Reconstructive Surgery, Department of Orthopaedic Surgery, Orthopaedic Hospital Research Center, University of California, Los Angeles, Los Angeles, California
| | - Xinli Zhang
- Section of Orthodontics, Division of Growth and Development, School of Dentistry, University of California, Los Angeles, Los Angeles, California.
| | - Chia Soo
- UCLA Division of Plastic and Reconstructive Surgery, Department of Orthopaedic Surgery, Orthopaedic Hospital Research Center, University of California, Los Angeles, Los Angeles, California.
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Prokopuk L, Stringer JM, Hogg K, Elgass KD, Western PS. PRC2 is required for extensive reorganization of H3K27me3 during epigenetic reprogramming in mouse fetal germ cells. Epigenetics Chromatin 2017; 10:7. [PMID: 28239420 PMCID: PMC5319108 DOI: 10.1186/s13072-017-0113-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/01/2017] [Indexed: 11/18/2022] Open
Abstract
Background Defining how epigenetic information is established in the germline during fetal development is key to understanding how epigenetic information is inherited and impacts on evolution and human health and disease. Results Here, we show that Polycomb Repressive Complex 2 is transiently localized in the nucleus of mouse fetal germ cells, while DNA methylation is removed from the germline. This coincides with significant enrichment of trimethylated lysine 27 on histone 3 near the nuclear lamina that is dependent on activity of the essential PRC2 catalytic proteins, Enhancer of Zeste 1 and/or 2. Conclusions Combined, these data reveal a role for Polycomb Repressive Complex 2 and trimethylated lysine 27 on histone 3 during germline epigenetic programming that we speculate is required to repress target sequences while DNA methylation is removed. Electronic supplementary material The online version of this article (doi:10.1186/s13072-017-0113-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lexie Prokopuk
- Department of Molecular and Translational Science, Centre for Genetic Diseases, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168 Australia
| | - Jessica M Stringer
- Department of Molecular and Translational Science, Centre for Genetic Diseases, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168 Australia
| | - Kirsten Hogg
- Department of Molecular and Translational Science, Centre for Genetic Diseases, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168 Australia
| | - Kirstin D Elgass
- Monash Micro Imaging, Monash University, Clayton, VIC 3800 Australia
| | - Patrick S Western
- Department of Molecular and Translational Science, Centre for Genetic Diseases, Hudson Institute of Medical Research, Monash University, Clayton, VIC 3168 Australia
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5
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Abstract
Much of what we know about the role of epigenetics in the determination of phenotype has come from studies of inbred mice. Some unusual expression patterns arising from endogenous and transgenic murine alleles, such as the Agouti coat color alleles, have allowed the study of variegation, variable expressivity, transgenerational epigenetic inheritance, parent-of-origin effects, and position effects. These phenomena have taught us much about gene silencing and the probabilistic nature of epigenetic processes. Based on some of these alleles, large-scale mutagenesis screens have broadened our knowledge of epigenetic control by identifying and characterizing novel genes involved in these processes.
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Affiliation(s)
- Marnie Blewitt
- Walter and Eliza Hall Institute, Melbourne, 3052 Victoria, Australia
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6
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The Mouse House: A brief history of the ORNL mouse-genetics program, 1947–2009. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2013; 753:69-90. [DOI: 10.1016/j.mrrev.2013.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/12/2013] [Indexed: 11/20/2022]
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Nakamura H, Cook RN, Justice MJ. Mouse Tenm4 is required for mesoderm induction. BMC DEVELOPMENTAL BIOLOGY 2013; 13:9. [PMID: 23521771 PMCID: PMC3614540 DOI: 10.1186/1471-213x-13-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 03/19/2013] [Indexed: 11/10/2022]
Abstract
Background Tenm4 is a mouse homolog of the Drosophila gene Tenascin-m (Ten-m (Odd oz)), which functions in motor neuron routing. Recently, a genome-wide association analysis for bipolar disorder identified a new susceptibility locus at TENM4 increasing the importance of understanding Tenm4. A series of Tenm4 mouse alleles showing a broad range of phenotypes were isolated after ENU mutagenesis. Here, we examine the timing and features of gastrulation failure in a loss of function allele. Results Embryonic mesoderm did not form in loss of function Tenm4m1/m1 mutant embryos. Genes normally expressed in embryonic mesoderm were not expressed in the mutant, the primitive streak did not form, and markers of the anteroposterior axis were not expressed or were mislocalized. The lack of embryonic mesoderm could not be attributed to poor proliferation of the epiblast, as normal numbers of dividing cells were observed. Epiblast cells maintained expression of Pou5f1 suggesting that they remain pluripotent, but they did not have the capacity to form any germ layer derivatives in teratomas, showing that the inability to induce mesoderm is cell autonomous. Misexpression of E-cadherin and N-cadherin suggest that the embryos did not undergo an epithelial-to-mesenchymal transition. In addition, Wnt signaling did not occur in the mutants, as assessed by the TOPGAL reporter assay, while a GSK3β inhibitor partially rescued the mutant embryos, and rescued TOPGAL reporter expression. Conclusions These data demonstrate that Tenm4 mutants fail to form a primitive streak and to induce embryonic mesoderm. Markers of anterior posterior patterning fail to be expressed or are mislocalized. Further, Tenm4 mutants lack the ability to differentiate in a cell autonomous manner. Together, our data suggest that embryos become impaired prior to E6.5 and as a result, Wnt signaling fails to occur; however, the involvement of other signaling pathways remains to be examined.
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Affiliation(s)
- Hisashi Nakamura
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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8
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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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9
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A novel allele of myosin VIIa reveals a critical function for the C-terminal FERM domain for melanosome transport in retinal pigment epithelial cells. J Neurosci 2010; 29:15810-8. [PMID: 20016096 DOI: 10.1523/jneurosci.4876-09.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mutations in the head and tail domains of the motor protein myosin VIIA (MYO7A) cause deaf-blindness (Usher syndrome type 1B, USH1B) and nonsyndromic deafness (DFNB2, DFNA11). The head domain binds to F-actin and serves as the MYO7A motor domain, but little is known about the function of the tail domain. In a genetic screen, we have identified polka mice, which carry a mutation (c.5742 + 5G > A) that affects splicing of the MYO7A transcript and truncates the MYO7A tail domain at the C-terminal FERM domain. In the inner ear, expression of the truncated MYO7A protein is severely reduced, leading to defects in hair cell development. In retinal pigment epithelial (RPE) cells, the truncated MYO7A protein is expressed at comparative levels to wild-type protein but fails to associate with and transport melanosomes. We conclude that the C-terminal FERM domain of MYO7A is critical for melanosome transport in RPE cells. Our findings also suggest that MYO7A mutations can lead to tissue-specific effects on protein levels, which may explain why some mutations in MYO7A lead to deafness without retinal impairment.
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10
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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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Hagarman JA, O'Brien TP. An essential gene mutagenesis screen across the highly conserved piebald deletion region of mouse chromosome 14. Genesis 2009; 47:392-403. [PMID: 19391113 DOI: 10.1002/dvg.20510] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The piebald deletion complex is a set of overlapping chromosomal deficiencies on distal mouse chromosome 14. We surveyed the functional genetic content of the piebald deletion region in an essential gene mutagenesis screen of 952 genomes to recover seven lethal mutants. The ENU-induced mutations were mapped to define genetic intervals using the piebald deletion panel. Lethal mutations included loci required for establishment of the left-right embryonic axis and a loss-of-function allele of Phr1 resulting in respiratory distress at birth. A functional map of the piebald region integrates experimental genetic data from the deletion panel, mutagenesis screen, and the targeted disruption of specific genes. A comparison of several genomic intervals targeted in regional mutagenesis screens suggests that the piebald region is characterized by a low gene density and high essential gene density with a distinct genomic content and organization that supports complex regulatory interactions and promotes evolutionary stability.
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Affiliation(s)
- James A Hagarman
- Department of Biomedical Sciences, Cornell University, Ithaca, New York
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12
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Abstract
Forward genetics has led to many discoveries and particularly in the field of Toll-like receptors (TLRs), it has played an important role in identifying key components involved in the innate sensing of pathogens. With the mouse genome fully sequenced and the ability to generate many mutant phenotypes through random germline mutagenesis, forward genetics has become an efficient means by which to identify key components involved in our immune response. In this chapter I provide a practical guide for performing germline mutagenesis in mice. I focus on the application of this technology to the identification of genes involved in TLR signaling.
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13
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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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14
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Tchekneva EE, Khuchua Z, Davis LS, Kadkina V, Dunn SR, Bachman S, Ishibashi K, Rinchik EM, Harris RC, Dikov MM, Breyer MD. Single amino acid substitution in aquaporin 11 causes renal failure. J Am Soc Nephrol 2008; 19:1955-64. [PMID: 18701606 DOI: 10.1681/asn.2008030296] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A screen of recessive mutations generated by the chemical mutagen n-ethyl-n-nitrosourea (ENU) mapped a new mutant locus (5772SB) termed sudden juvenile death syndrome (sjds) to chromosome 7 in mice. These mutant mice, which exhibit severe proximal tubule injury and formation of giant vacuoles in the renal cortex, die from renal failure, a phenotype that resembles aquaporin 11 (Aqp11) knockout mice. In this report, the ENU-induced single-nucleotide variant (sjds mutation) is identified. To determine whether this variant, which causes an amino acid substitution (Cys227Ser) in the predicted E-loop region of aquaporin 11, is responsible for the sjds lethal renal phenotype, Aqp11-/sjds compound heterozygous mice were generated from Aqp11 +/sjds and Aqp11 +/- intercrosses. The compound heterozygous Aqp11 -/sjds offspring exhibited a lethal renal phenotype (renal failure by 2 wk), similar to the Aqp11 sjds/sjds and Aqp11-/- phenotypes. These results demonstrate that the identified mutation causes renal failure in Aqp11 sjds/sjds mutant mice, providing a model for better understanding of the structure and function of aquaporin 11 in renal physiology.
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Affiliation(s)
- Elena E Tchekneva
- Division of Nephrology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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15
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Georgel P, Du X, Hoebe K, Beutler B. ENU mutagenesis in mice. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008; 415:1-16. [PMID: 18370145 DOI: 10.1007/978-1-59745-570-1_1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Forward genetics has led to many "breakthrough" discoveries, and with the mouse genome almost fully sequenced, the creation of phenotypes through random germline mutagenesis has become an efficient means by which to find the function of yet undescribed genes. In this chapter, we will provide a practical guideline for performing germline mutagenesis in mice. In particular, we will focus on the application of this technology to identify genes that are essential to innate immune defense.
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Affiliation(s)
- Philippe Georgel
- Laboratoire d'Immunogénétique Moléculaire Humaine, Centre de Recherche en Immunologie et Hématologie, Faculté de Médecine, Strasbourg Cedex, France
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16
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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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17
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Caspary T, Anderson KV. Uncovering the uncharacterized and unexpected: unbiased phenotype-driven screens in the mouse. Dev Dyn 2006; 235:2412-23. [PMID: 16724327 DOI: 10.1002/dvdy.20853] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Phenotype-based chemical mutagenesis screens for mouse mutations have undergone a transformation in the past five years from a potential approach to a practical tool. This change has been driven by the relative ease of identifying causative mutations now that the complete genome sequence is available. These unbiased screens make it possible to identify genes, gene functions and processes that are uniquely important to mammals. In addition, because chemical mutagenesis generally induces point mutations, these alleles often uncover previously unappreciated functions of known proteins. Here we provide examples of the success stories from forward genetic screens, emphasizing the examples that illustrate the discovery of mammalian-specific processes that could not be discovered in other model organisms. As the efficiency of sequencing and mutation detection continues to improve, it is likely that forward genetic screens will provide an even more important part of the repertoire of mouse genetics in the future.
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Affiliation(s)
- Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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18
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Papathanasiou P, Goodnow CC. Connecting mammalian genome with phenome by ENU mouse mutagenesis: gene combinations specifying the immune system. Annu Rev Genet 2006; 39:241-62. [PMID: 16053407 DOI: 10.1146/annurev.genet.39.110304.095817] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human and mouse genome sequences bring closer the goal of understanding how characteristics of adult mammalian physiology and pathology are encoded by DNA. Here we review the challenge of understanding how genes specify mammalian traits, with particular focus on the cells and behavior of the immune system. Summarized is the emerging experience, advantages, and limitations of using ethylnitrosourea (ENU) to modify the mouse genome and select informative variants by phenotypic screens, yielding two main conclusions. First, ENU-induced variation provides an eminently feasible route to understanding how the genome encodes important mammalian processes without any prior assumptions about genes, their chromosomal locations, or expression patterns. Second, ENU alleles match those arising by natural variation. By changing individual protein domains or splice products, these alleles reveal separate gene functions specified through protein combinations.
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Affiliation(s)
- Peter Papathanasiou
- Australian Cancer Research Foundation Genetics Laboratory and Australian Phenomics Facility, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601 Australia.
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19
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Kennedy CL, O'Bryan MK. N-ethyl-N-nitrosourea (ENU) mutagenesis and male fertility research. Hum Reprod Update 2006; 12:293-301. [PMID: 16436467 DOI: 10.1093/humupd/dmk004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Male infertility affects about 1 in 25 men in the western world. Conversely, there is an urgent requirement for additional male-based contraceptives, yet progress in both areas has been severely hampered by a lack of knowledge of the biochemistry and physiology of male reproductive function. It is only through a thorough knowledge of these processes that we can hope to insightfully regulate male reproductive function. Without doubt, mouse models will form an important foundation in any future process. In recent years, the chemical mutagen N-ethyl-N-nitrosourea (ENU) has been used widely to identify genes essential for a range of biological systems including male infertility. These studies have shown random mutagenesis is an attractive means of identifying key genes for male fertility. This technique has distinct, but complementary advantages compared to knockout technologies. Specifically, it allows the removal of researcher bias whereby only pre-conceived genes are tested for function; it produces mice with a guaranteed phenotype and allows for the production of allelic series of mice to dissect all aspects of gene function. ENU mouse mutagenesis programs will enable advances in the diagnosis and treatment of human male infertility and ultimately aid in the development of novel male-based contraceptives.
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Affiliation(s)
- C L Kennedy
- The Centre for Reproduction and Development, Monash Institute of Medical Research and the ARC Centre of Excellence in Biotechnology and Development, Monash University, Melbourne, Australia
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20
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Abstract
In the mouse, random mutagenesis with N-ethyl-N-nitrosourea (ENU) has been used since the 1970s in forward mutagenesis screens. However, only in the last decade has ENU mutagenesis been harnessed to generate a myriad of new mouse mutations in large-scale genetic screens and focused, smaller efforts. The development of additional genetic tools, such as balancer chromosomes, refinements in genetic mapping strategies, and evolution of specialized assays, has allowed these screens to achieve new levels of sophistication. The impressive productivity of these screens has led to a deluge of mouse mutants that wait to be harnessed. Here the basic large- and small-scale strategies are described, as are the basics of screen design. Finally, and importantly, this review describes the mechanisms by which such mutants may be accessed now and in the future. Thus, this review should serve both as an overview of the power of forward mutagenesis in the mouse and as a resource for those interested in developing their own screens, adding onto existing efforts, or obtaining specific mouse mutants that have already been generated.
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Affiliation(s)
- Sabine P Cordes
- Samuel Lunenfeld Research Institute, Room 865, Mt. Sinai Hospital, Toronto, Ontario M5G 1X5, Canada.
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21
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Michaud EJ, Culiat CT, Klebig ML, Barker PE, Cain KT, Carpenter DJ, Easter LL, Foster CM, Gardner AW, Guo ZY, Houser KJ, Hughes LA, Kerley MK, Liu Z, Olszewski RE, Pinn I, Shaw GD, Shinpock SG, Wymore AM, Rinchik EM, Johnson DK. Efficient gene-driven germ-line point mutagenesis of C57BL/6J mice. BMC Genomics 2005; 6:164. [PMID: 16300676 PMCID: PMC1325271 DOI: 10.1186/1471-2164-6-164] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Accepted: 11/21/2005] [Indexed: 11/24/2022] Open
Abstract
Background Analysis of an allelic series of point mutations in a gene, generated by N-ethyl-N-nitrosourea (ENU) mutagenesis, is a valuable method for discovering the full scope of its biological function. Here we present an efficient gene-driven approach for identifying ENU-induced point mutations in any gene in C57BL/6J mice. The advantage of such an approach is that it allows one to select any gene of interest in the mouse genome and to go directly from DNA sequence to mutant mice. Results We produced the Cryopreserved Mutant Mouse Bank (CMMB), which is an archive of DNA, cDNA, tissues, and sperm from 4,000 G1 male offspring of ENU-treated C57BL/6J males mated to untreated C57BL/6J females. Each mouse in the CMMB carries a large number of random heterozygous point mutations throughout the genome. High-throughput Temperature Gradient Capillary Electrophoresis (TGCE) was employed to perform a 32-Mbp sequence-driven screen for mutations in 38 PCR amplicons from 11 genes in DNA and/or cDNA from the CMMB mice. DNA sequence analysis of heteroduplex-forming amplicons identified by TGCE revealed 22 mutations in 10 genes for an overall mutation frequency of 1 in 1.45 Mbp. All 22 mutations are single base pair substitutions, and nine of them (41%) result in nonconservative amino acid substitutions. Intracytoplasmic sperm injection (ICSI) of cryopreserved spermatozoa into B6D2F1 or C57BL/6J ova was used to recover mutant mice for nine of the mutations to date. Conclusions The inbred C57BL/6J CMMB, together with TGCE mutation screening and ICSI for the recovery of mutant mice, represents a valuable gene-driven approach for the functional annotation of the mammalian genome and for the generation of mouse models of human genetic diseases. The ability of ENU to induce mutations that cause various types of changes in proteins will provide additional insights into the functions of mammalian proteins that may not be detectable by knockout mutations.
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Affiliation(s)
- Edward J Michaud
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
- The University of Tennessee-Oak Ridge National Laboratory Graduate School of Genome Science and Technology, Oak Ridge, TN 37830, USA
| | - Cymbeline T Culiat
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
- The University of Tennessee-Oak Ridge National Laboratory Graduate School of Genome Science and Technology, Oak Ridge, TN 37830, USA
| | - Mitchell L Klebig
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
- The University of Tennessee-Oak Ridge National Laboratory Graduate School of Genome Science and Technology, Oak Ridge, TN 37830, USA
- Department of Biochemistry, Cellular, and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
| | - Paul E Barker
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - KT Cain
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Debra J Carpenter
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Lori L Easter
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Carmen M Foster
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Alysyn W Gardner
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - ZY Guo
- SpectruMedix, 2124 Old Gatesburg Road, State College, PA 16803, USA
| | - Kay J Houser
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Lori A Hughes
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Marilyn K Kerley
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Zhaowei Liu
- SpectruMedix, 2124 Old Gatesburg Road, State College, PA 16803, USA
| | - Robert E Olszewski
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Irina Pinn
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Ginger D Shaw
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Sarah G Shinpock
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Ann M Wymore
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
| | - Eugene M Rinchik
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
- The University of Tennessee-Oak Ridge National Laboratory Graduate School of Genome Science and Technology, Oak Ridge, TN 37830, USA
- Department of Biochemistry, Cellular, and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA
- Taconic, 273 Hover Avenue, Germantown, NY 12526, USA
| | - Dabney K Johnson
- Life Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831, USA
- The University of Tennessee-Oak Ridge National Laboratory Graduate School of Genome Science and Technology, Oak Ridge, TN 37830, USA
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22
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Chick WSH, Mentzer SE, Carpenter DA, Rinchik EM, Johnson D, You Y. X-ray-induced deletion complexes in embryonic stem cells on mouse chromosome 15. Mamm Genome 2005; 16:661-71. [PMID: 16245023 DOI: 10.1007/s00335-005-0011-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Accepted: 05/31/2005] [Indexed: 12/20/2022]
Abstract
Chromosomal deletions have long been used as genetic tools in dissecting the functions of complex genomes, and new methodologies are still being developed to achieve the maximum coverage. In the mouse, where the chromosomal deletion coverage is far less extensive than that in Drosophila, substantial coverage of the genome with deletions is strongly desirable. This article reports the generation of three deletion complexes in the distal part of mouse Chromosome (Chr) 15. Chromosomal deletions were efficiently induced by X rays in embryonic stem (ES) cells around the Otoconin 90 (Oc 90), SRY-box-containing gene 10 (Sox 10), and carnitine palmitoyltransferase 1b (Cpt 1 b) loci. Deletions encompassing the Oc 90 and Sox 10 loci were transmitted to the offspring of the chimeric mice that were generated from deletion-bearing ES cells. Whereas deletion complexes encompassing the Sox 10 and the Cpt 1 b loci overlap each other, no overlap of the Oc 90 complex with the Sox 10 complex was found, possibly indicating the existence of a haploinsufficient gene located between Oc 90 and Sox 10. Deletion frequency and size induced by X rays depend on the selective locus, possibly reflecting the existence of haplolethal genes in the vicinity of these loci that yield fewer and smaller deletions. Deletions induced in ES cells by X rays vary in size and location of breakpoints, which makes them desirable for mapping and for functional genomics studies.
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Affiliation(s)
- Wallace S H Chick
- Graduate School of Genome Sciences and Technology, The University of Tennessee, Knoxville, Tennessee 37996, USA
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23
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Hoebe K, Beutler B. Unraveling innate immunity using large scale N-ethyl-N-nitrosourea mutagenesis. ACTA ACUST UNITED AC 2005; 65:395-401. [PMID: 15853894 DOI: 10.1111/j.1399-0039.2005.00369.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
With the mouse genome almost entirely sequenced and readily accessible to all who wish to examine it, the challenge across most biological disciplines now lies in the decipherment of gene and protein function rather than in the realm of gene identification per se. In the field of innate immunity, forward genetic methods have repeatedly been applied to identify key sensors, adapters, and effector molecules. However, most spontaneous mutations that affect innate immune function have been mapped and cloned, and the need for new monogenic phenotypes has been felt evermore keenly. N-Ethyl-N-nitrosourea (ENU) mutagenesis is an efficient tool for the creation of aberrant monogenic innate immune response phenotypes. In this review, we will discuss the potential of the forward genetic approach and ENU mutagenesis to identify new genes and new functions of known genes related to innate immunity.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport/genetics
- Adaptor Proteins, Vesicular Transport/physiology
- Animals
- Antigens, Differentiation/genetics
- Antigens, Differentiation/physiology
- CD36 Antigens/genetics
- CD36 Antigens/physiology
- Ethylnitrosourea/pharmacology
- Gene Targeting
- Genes, Recessive
- Genetic Techniques
- Humans
- Immunity, Innate/genetics
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Mice
- Mice, Knockout
- Models, Immunological
- Mutagenesis
- Mutagens/pharmacology
- Myeloid Differentiation Factor 88
- Phenotype
- Receptors, Cell Surface/physiology
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Receptors, Interleukin-1/genetics
- Receptors, Interleukin-1/physiology
- Toll-Like Receptors
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Affiliation(s)
- K Hoebe
- Department of Immunology IMM-31, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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24
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Fernández-Valdivia R, Zhang Y, Pai S, Metzker ML, Schumacher A. l7Rn6 encodes a novel protein required for clara cell function in mouse lung development. Genetics 2005; 172:389-99. [PMID: 16157679 PMCID: PMC1456166 DOI: 10.1534/genetics.105.048736] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The highly secretory Clara cells play a pivotal role in protecting the lung against inflammation and oxidative stress. This study reports the positional cloning of a novel protein required for Clara cell physiology in mouse lung development. The perinatal lethal N-ethyl-N-nitrosourea-induced l7Rn6(4234SB) allele contained a nonsense mutation in the previously hypothetical gene NM_026304 on chromosome 7. Whereas l7Rn6 mRNA levels were indistinguishable from wild type, l7Rn6(4234SB) homozygotes exhibited decreased expression of the truncated protein, suggesting protein instability. During late gestation, l7Rn6 was widely expressed in the cytoplasm of lung epithelial cells, whereas perinatal expression was restricted to the bronchiolar epithelium. Homozygosity for the l7Rn6(4234SB) allele did not affect early steps in lung patterning, growth, or cellular differentiation. Rather, mutant lungs demonstrated severe emphysematous enlargement of the distal respiratory sacs at birth. Clara cell pathophysiology was evident from decreased cytoplasmic CCSP and SP-B protein levels, enlargement and disorganization of the Golgi complex, and formation of aberrant vesicular structures. Additional support for a role in the secretory pathway derived from l7Rn6 localization to the endoplasmic reticulum. Thus, l7Rn6 represents a novel protein required for organization and/or function of the secretory apparatus in Clara cells in mouse lung.
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25
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Abstract
Humans are mammals, not bacteria or plants, yeast or nematodes, insects or fish. Mice are also mammals, but unlike gorilla and goat, fox and ferret, giraffe and jackal, they are suited perfectly to the laboratory environment and genetic experimentation. In this review, we will summarize the tools, tricks and techniques for executing forward genetic screens in the mouse and argue that this approach is now accessible to most biologists, rather than being the sole domain of large national facilities and specialized genetics laboratories.
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Affiliation(s)
- Benjamin T Kile
- Division of Cancer and Hematology, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3050, Victoria, Australia.
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26
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Lossie AC, Nakamura H, Thomas SE, Justice MJ. Mutation of l7Rn3 shows that Odz4 is required for mouse gastrulation. Genetics 2005; 169:285-99. [PMID: 15489520 PMCID: PMC1448887 DOI: 10.1534/genetics.104.034967] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2004] [Accepted: 10/08/2004] [Indexed: 11/18/2022] Open
Abstract
A mouse homolog of the Drosophila pair-rule gene Odd Oz (Odz4) maps to the critical region of the l7Rn3 locus on mouse chromosome 7. Here we show that Odz4 is an excellent candidate for this allelic series because (1) it spans the entire critical region, (2) the phenotypes correlate with embryonic expression, (3) the complex genetic inheritance of the alleles is consistent with complex transcriptional regulation, and (4) one allele has a mutation in a conserved amino acid. Odz4 uses five alternate promoters that encode both secreted and membrane-bound proteins. Intragenic complementation of the l7Rn3 alleles is consistent with these multiple-protein isoforms. Further, the allelic series shows that Odz4 is required to establish the anterior-posterior axis of the gastrulating mouse embryo and is necessary later for mesoderm-derived tissues such as somites, heart, and skeleton. Sequencing of RT-PCR products from five of the six alleles reveals a nonconservative amino acid change in the l7Rn3(m4) allele. This amino acid is important evolutionarily, as it is conserved to Drosophila. Together, our data indicate that Odz4 is mutated in the l7Rn3 allele series and performs roles in the mouse brain, heart, and embryonic patterning similar to those of its Drosophila counterpart.
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Affiliation(s)
- Amy C Lossie
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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27
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Ovcharenko I, Loots GG, Nobrega MA, Hardison RC, Miller W, Stubbs L. Evolution and functional classification of vertebrate gene deserts. Genome Res 2004; 15:137-45. [PMID: 15590943 PMCID: PMC540279 DOI: 10.1101/gr.3015505] [Citation(s) in RCA: 192] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Large tracts of the human genome, known as gene deserts, are devoid of protein-coding genes. Dichotomy in their level of conservation with chicken separates these regions into two distinct categories, stable and variable. The separation is not caused by differences in rates of neutral evolution but instead appears to be related to different biological functions of stable and variable gene deserts in the human genome. Gene Ontology categories of the adjacent genes are strongly biased toward transcriptional regulation and development for the stable gene deserts, and toward distinctively different functions for the variable gene deserts. Stable gene deserts resist chromosomal rearrangements and appear to harbor multiple distant regulatory elements physically linked to their neighboring genes, with the linearity of conservation invariant throughout vertebrate evolution.
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Affiliation(s)
- Ivan Ovcharenko
- Energy, Environment, Biology, and Institutional Computing, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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28
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29
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Bergstrom DE, Bergstrom RA, Munroe RJ, Lee BK, Browning VL, You Y, Eicher EM, Schimenti JC. Overlapping deletions spanning the proximal two-thirds of the mouse t complex. Mamm Genome 2004; 14:817-29. [PMID: 14724736 PMCID: PMC2583125 DOI: 10.1007/s00335-003-2298-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2003] [Accepted: 07/17/2003] [Indexed: 11/25/2022]
Abstract
Chromosome deletion complexes in model organisms serve as valuable genetic tools for the functional and physical annotation of complex genomes. Among their many roles, deletions can serve as mapping tools for simple or quantitative trait loci (QTLs), genetic reagents for regional mutagenesis experiments, and, in the case of mice, models of human contiguous gene deletion syndromes. Deletions also are uniquely suited for identifying regions of the genome containing haploinsufficient or imprinted loci. Here we describe the creation of new deletions at the proximal end of mouse Chromosome (Chr) 17 by using the technique of ES cell irradiation and the extensive molecular characterization of these and previously isolated deletions that, in total, cover much of the mouse t complex. The deletions are arranged in five overlapping complexes that collectively span about 25 Mbp. Furthermore, we have integrated each of the deletion complexes with physical data from public and private mouse genome sequences, and our own genetic data, to resolve some discrepancies. These deletions will be useful for characterizing several phenomena related to the t complex and t haplotypes, including transmission ratio distortion, male infertility, and the collection of t haplotype embryonic lethal mutations. The deletions will also be useful for mapping other loci of interest on proximal Chr 17, including T-associated sex reversal ( Tas) and head-tilt ( het). The new deletions have thus far been used to localize the recently identified t haplolethal ( Thl1) locus to an approximately 1.3-Mbp interval.
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Affiliation(s)
- David E Bergstrom
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
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30
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Curtis DJ. Modifier screens in the mouse: time to move forward with reverse genetics. Proc Natl Acad Sci U S A 2004; 101:7209-10. [PMID: 15128944 PMCID: PMC409896 DOI: 10.1073/pnas.0401969101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- David J Curtis
- Rotary Bone Marrow Research Laboratories, Royal Melbourne Hospital, Parkville, 3050 Victoria, Australia.
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31
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Abstract
The rapid development and characterization of the mouse genome sequence, coupled with comparative sequence analysis of human, has been paralleled by a reinforced enthusiasm for mouse functional genomics. The way to uncover the in vivo function of genes is to analyze the phenotypes of the mutant animals. From this standpoint, the mouse is a suitable and valuable model organism in the studies of functional genomics. Therefore, there have been enormous efforts to enrich the list of the mutant mice. Such a trend emphasizes the random mutagenesis, including ENU mutagenesis and gene-trap mutagenesis, to obtain a large stock of mutant mice. However, since various mutant alleles are needed to precisely characterize the role of a gene in vivo, mutations should be designed. The simplicity and utility of transgenic technology can satisfy this demand. The combination of RNA interference with transgenic technology will provide more opportunities for researchers. Nevertheless, gene targeting can solely define the in vivo function of a gene without a doubt. Thus, transgenesis and gene targeting will be the major strategies in the field of functional genomics.
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Affiliation(s)
- Young Hoon Sung
- Samsung Biomedical Research Institute and Department of Molecular Cell Biology, Sungkyunkwan University, School of Medicine, Suwon 440-746, Korea
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32
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Abstract
DNA and RNA quantifications are widely used in biological and biomedical research. In the last ten years, many technologies have been developed to enable automated and high-throughput analyses. In this review, we first give a brief overview of how DNA and RNA quantifications are carried out. Then, five technologies (microarrays, SAGE, differential display, real time PCR and real competitive PCR) are introduced, with an emphasis on how these technologies can be applied and what their limitations are. The technologies are also evaluated in terms of a few key aspects of nucleic acids quantification such as accuracy, sensitivity, specificity, cost and throughput.
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Affiliation(s)
- Chunming Ding
- Bioinformatics Program and Center for Advanced Biotechnology, Boston University, Boston, MA 02215, USA.
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33
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Holme RH, Steel KP. Progressive hearing loss and increased susceptibility to noise-induced hearing loss in mice carrying a Cdh23 but not a Myo7a mutation. J Assoc Res Otolaryngol 2003; 5:66-79. [PMID: 14648237 PMCID: PMC2538366 DOI: 10.1007/s10162-003-4021-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2003] [Accepted: 09/03/2003] [Indexed: 02/07/2023] Open
Abstract
Exposure to intense noise can damage the stereocilia of sensory hair cells in the inner ear. Since stereocilia play a vital role in the transduction of sound from a mechanical stimulus into an electrical one, this pathology is thought to contribute to noise-induced hearing loss. Mice homozygous for null mutations in either the myosin VIIa ( Myo7a) or cadherin 23 ( Cdh23) genes are deaf and have disorganized stereocilia bundles. We show that mice heterozygous for a presumed null allele of Cdh23 ( Cdh23(v)) have low- and high-frequency hearing loss at 5-6 weeks of age, the high-frequency component of which worsens with increasing age. We also show that noise-induced hearing loss in 11-12-week-old Cdh23(v) heterozygotes is two times greater than for wild-type littermates. Interestingly, these effects are dependent upon the genetic background on which the Cdh23(v) mutation is carried. Noise-induced hearing loss in 11-12-week-old mice heterozygous for a null allele of Myo7a ( Myo7a(4626SB)) is not significantly different from wild-type littermates. CDH23 is the first gene known to cause deafness in the human population to be linked with predisposition to noise-induced hearing loss.
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Affiliation(s)
- Ralph H. Holme
- MRC Institute of Hearing Research, University Park, Nottingham, NG7 2RD, UK
| | - Karen P. Steel
- MRC Institute of Hearing Research, University Park, Nottingham, NG7 2RD, UK
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34
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Abstract
More than ten large-scale mutagenesis projects are now generating hundreds of novel mouse mutants. Projects employ a wide variety of strategies and screens: targeting as much as the whole genome, part of a chromosome or just single genes. In this commentary, we consider the pros and cons of different tactics. We highlight issues of cost, efficiency and defend the impact of this mutagenesis program in an era of sophisticated conditional knockouts and advanced transgenic lines. Given the significant difficulties of adequately phenotyping and mapping randomly generated mutations that cover the whole genome, we tend to favor regional and gene-targeted screens. Whatever the choice of method, whole genome sequence data combined with detailed transcriptome and proteome surveys promise to significantly improve the efficiency with which series of mutations in a large subset of mammalian genes can be generated and cloned.
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Affiliation(s)
- R W Williams
- Center for Genomics and Bioinformatics, University of Tennessee Health Science Center, Madison Avenue, Memphis, TN 38163, USA.
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35
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Klebig ML, Wall MD, Potter MD, Rowe EL, Carpenter DA, Rinchik EM. Mutations in the clathrin-assembly gene Picalm are responsible for the hematopoietic and iron metabolism abnormalities in fit1 mice. Proc Natl Acad Sci U S A 2003; 100:8360-5. [PMID: 12832620 PMCID: PMC166234 DOI: 10.1073/pnas.1432634100] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recessive N-ethyl-N-nitrosourea (ENU)-induced mutations recovered at the fitness-1 (fit1) locus in mouse chromosome 7 cause hematopoietic abnormalities, growth retardation, and shortened life span, with varying severity of the defects in different alleles. Abnormal iron distribution and metabolism and frequent scoliosis have also been associated with an allele of intermediate severity (fit14R). We report that fit14R, as well as the most severe fit15R allele, are nonsense point mutations in the mouse ortholog of the human phosphatidylinositol-binding clathrin assembly protein (PICALM) gene, whose product is involved in clathrin-mediated endocytosis. A variety of leukemias and lymphomas have been associated with translocations that fuse human PICALM with the putative transcription factor gene AF10. The Picalmfit1-5R and Picalmfit1-4R mutations are splice-donor alterations resulting in transcripts that are less abundant than normal and missing exons 4 and 17, respectively. These exon deletions introduce premature termination codons predicted to truncate the proteins near the N and C termini, respectively. No mutations in the genes encoding Picalm, clathrin, or components of the adaptor protein complex 2 (AP2) have been previously described in which the suite of disorders present in the Picalmfit1 mutant mice is apparent. These mutants thus provide unique models for exploring how the endocytic function of mouse Picalm and the transport processes mediated by clathrin and the AP2 complex contribute to normal hematopoiesis, iron metabolism, and growth.
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Affiliation(s)
- Mitchell L Klebig
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
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36
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Abstract
In the postgenomic era the mouse will be central to the challenge of ascribing a function to the 40,000 or so genes that constitute our genome. In this review, we summarize some of the classic and modern approaches that have fueled the recent dramatic explosion in mouse genetics. Together with the sequencing of the mouse genome, these tools will have a profound effect on our ability to generate new and more accurate mouse models and thus provide a powerful insight into the function of human genes during the processes of both normal development and disease.
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37
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Russ A, Stumm G, Augustin M, Sedlmeier R, Wattler S, Nehls M. Random mutagenesis in the mouse as a tool in drug discovery. Drug Discov Today 2002; 7:1175-83. [PMID: 12547018 DOI: 10.1016/s1359-6446(02)02515-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The flood of raw information generated by large-scale data acquisition technologies in genomics, microarrays and proteomics is changing the early stages of the drug discovery process. Although many more potential drug targets are now available compared with the pre-genomics era, knowledge about the physiological context in which these targets act--information crucial to both discovery and development--is scarce. Random mutagenesis strategies in the mouse provide scalable approaches for both the gene-driven validation of candidate targets in vivo and the discovery of new physiological pathways by phenotype-driven screens.
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Affiliation(s)
- Andreas Russ
- Ingenium Pharmaceuticals, Fraunhoferstrasse 13, D-82152 Martinsried, Germany.
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38
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Abstract
Mutations in myosin VIIa (Myo7a) and cadherin 23 (Cdh23) cause deafness in shaker1 (sh1) and waltzer (v) mouse mutants respectively. In humans, mutations in these genes cause Usher's syndrome type 1B and D respectively, as well as certain forms of non-syndromic deafness. Examination of the organ of Corti from shaker1 and waltzer mice has shown that these genes are required for the proper organisation of hair cell stereocilia. Here we show that at embryonic day 18.5, the outer hair cells of Cdh23(v) homozygote mutant mice appear immature, projecting fewer recognisable stereocilia than heterozygote controls, and by post-natal day (P) 4 their stereocilia are arranged in a disorganised pattern rather than in the regular 'V'-shape seen in heterozygotes. Inner hair cell stereocilia are also disorganised in Cdh23(v) mutant homozygotes. Myo7a was expressed normally in the hair cells of P0 Cdh23(v2J) mutants demonstrating that cadherin 23 is not required for Myo7a expression at this stage. No stereocilia defects were observed in P4 Cdh23(v)/Myo7a(4626SB) double heterozygotes (+/Cdh23(v) +/Myo7a(4626SB)) and neither the Cdh23(v) nor Myo7a(4626SB) homozygote phenotypes were affected by the presence of one mutant copy of Myo7a or Cdh23 respectively. The hair cell phenotype of double homozygote mutant mice did not differ from single Myo7a(4626SB) homozygote mutants. Finally, we found no significant correlation between loss of hearing and double heterozygosity for mutations in Cdh23 and Myo7a in mice aged between 7.5 and 10 months. These findings suggest that Cdh23 and Myo7a are both required for establishing and/or maintaining the proper organisation of the stereocilia bundle and that they do not genetically interact to affect this process nor to cause age-related hearing loss.
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Affiliation(s)
- Ralph H Holme
- MRC Institute of Hearing Research, University of Nottingham, Nottingham NG7 2RD, UK
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39
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Beckers J, Hrabé de Angelis M. Large-scale mutational analysis for the annotation of the mouse genome. Curr Opin Chem Biol 2002; 6:17-23. [PMID: 11827818 DOI: 10.1016/s1367-5931(01)00277-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
After sequencing the human and mouse genomes, the annotation of these sequences with biological functions is an important challenge in genomic research. A major tool to analyse gene function on the organismal level is the analysis of mutant phenotypes. Because of its genetic and physiological similarity to man, the mouse has become the model organism of choice for the study of genetic diseases. In addition, there is at the moment no other vertebrate for which versatile techniques to manipulate the genome are as well developed. Several mouse mutagenesis projects have provided the proof-of-principle that a systematic and comprehensive mutagenesis of every gene in the mammalian genome will be feasible. An exhaustive functional annotation of the mammalian genome can only be achieved in a combination of phenotype- and gene-driven approaches in large- and small-scale academic and private projects. Major challenges will be to develop standardised phenotyping protocols for the clinical and pathological characterisation of mouse mutants, the improvement of mutation detection methods and the dissemination of resources and data. Beyond gene annotation, it will be necessary to understand how gene functions are integrated into the complex network of regulatory interactions in the cell.
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Affiliation(s)
- Johannes Beckers
- Institute of Experimental Genetics, GSF-National Research Center for Environment and Health, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.
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40
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Rinchik EM, Carpenter DA, Johnson DK. Functional annotation of mammalian genomic DNA sequence by chemical mutagenesis: a fine-structure genetic mutation map of a 1- to 2-cM segment of mouse chromosome 7 corresponding to human chromosome 11p14-p15. Proc Natl Acad Sci U S A 2002; 99:844-9. [PMID: 11792855 PMCID: PMC117393 DOI: 10.1073/pnas.022628199] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eleven independent, recessive, N-ethyl-N-nitrosourea-induced mutations that map to a approximately 1- to 2-cM region of mouse chromosome (Chr) 7 homologous to human Chr 11p14-p15 were recovered from a screen of 1,218 gametes. These mutations were initially identified in a hemizygous state opposite a large p-locus deletion and subsequently were mapped to finer genomic intervals by crosses to a panel of smaller p deletions. The 11 mutations also were classified into seven complementation groups by pairwise crosses. Four complementation groups were defined by seven prenatally lethal mutations, including a group (l7R3) comprised of two alleles of obvious differing severity. Two allelic mutations (at the psrt locus) result in a severe seizure and runting syndrome, but one mutation (at the fit2 locus) results in a more benign runting phenotype. This experiment has added seven loci, defined by phenotypes of presumed point mutations, to the genetic map of a small (1-2 cM) region of mouse Chr 7 and will facilitate the task of functional annotation of DNA sequence and transcription maps both in the mouse and the corresponding human 11p14-p15 homology region.
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Affiliation(s)
- Eugene M Rinchik
- Life Sciences Division, Oak Ridge National Laboratory, P. O. Box 2009, Oak Ridge, TN 37831-8077, USA.
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41
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Abstract
Hereditary isolated hearing loss is genetically highly heterogeneous. Over 100 genes are predicted to cause this disorder in humans. Sixty loci have been reported and 24 genes underlying 28 deafness forms have been identified. The present epistemic stage in the realm consists in a preliminary characterization of the encoded proteins and the associated defective biological processes. Since for several of the deafness forms we still only have fuzzy notions of their pathogenesis, we here adopt a presentation of the various deafness forms based on the site of the primary defect: hair cell defects, nonsensory cell defects, and tectorial membrane anomalies. The various deafness forms so far studied appear as monogenic disorders. They are all rare with the exception of one, caused by mutations in the gene encoding the gap junction protein connexin26, which accounts for between one third to one half of the cases of prelingual inherited deafness in Caucasian populations.
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Affiliation(s)
- C Petit
- Unité de Génétique des Déficits Sensoriels, CNRS URA 1968, Institut Pasteur, 25 rue du Dr Roux, Paris cedex 15, 75724 France.
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42
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Richie ER, Schumacher A, Angel JM, Holloway M, Rinchik EM, Magnuson T. The Polycomb-group gene eed regulates thymocyte differentiation and suppresses the development of carcinogen-induced T-cell lymphomas. Oncogene 2002; 21:299-306. [PMID: 11803473 DOI: 10.1038/sj.onc.1205051] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2001] [Revised: 09/25/2001] [Accepted: 10/09/2001] [Indexed: 11/08/2022]
Abstract
The mouse Polycomb-group gene, embryonic ectoderm development (eed), appears to regulate cellular growth and differentiation in a developmental and tissue specific manner. During embryogenesis, eed regulates axial patterning, whereas in the adult eed represses proliferation of myeloid and B cell precursors. The present report demonstrates two novel functional activities of eed: alteration of thymocyte maturation and suppression of thymic lymphoma development. Mice that inherit the viable hypomorphic 17Rn5(1989SB) eed allele sustain a partial developmental block at or before the CD4(-)CD8(-)CD44(-)CD25(+) stage of thymocyte differentiation. Furthermore, mice that are homozygous or heterozygous for the hypomorphic eed allele have an increased incidence and decreased latency of N-methyl-N-nitrosourea-induced thymic lymphoma compared to wild-type littermates. These findings support the notion that Polycomb-group genes exert pleiotropic effects dictated by developmental stage and cellular context.
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Affiliation(s)
- Ellen R Richie
- Department of Carcinogenesis, The University of Texas, M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957, USA.
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Abstract
Usher syndrome (USH) is defined by the association of sensorineural deafness and visual impairment due to retinitis pigmentosa. The syndrome has three distinct clinical subtypes, referred to as USH1, USH2, and USH3. Each subtype is genetically heterogeneous, and 12 loci have been detected so far. Four genes have been identified, namely, USH1B, USH1C, USH1D, and USH2A. USH1B, USH1C, and USH1D encode an unconventional myosin (myosin VIIA), a PDZ domain-containing protein (harmonin), and a cadherin-like protein (cadherin-23), respectively. Mutations of these genes cause primary defects of the sensory cells in the inner ear, and probably also in the retina. In the inner ear, the USH1 genes, I propose, are involved in the same signaling pathway, which may control development and/or maintenance of the hair bundles of sensory cells via an adhesion force (a) at the junctions between these cells and supporting cells and (b) at the level of the lateral links that interconnect the stereocilia. In contrast, the molecular pathogenesis of USH2A, which is owing to a defect of a novel extracellular matrix protein, is likely to be different from that of USH1.
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Affiliation(s)
- C Petit
- Unité de Génétique des Déficits Sensoriels, CNRS URA 1968 Institut Pasteur, Paris, Cedex 15, 75724 France.
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Abstract
With the completion of the human genome, sequence analysis of gene function will move into the center of future genome research. One of the key strategies for studying gene function involves the genetic dissection of biological processes in animal models. Mouse mutants are of particular importance for the analysis of disease pathogenesis and transgenic techniques, and gene targeting have become routine tools. Recently, phenotype-driven strategies using chemical mutagenesis have been the target of increasing interest. In this review, the current state of ENU mutagenesis and its application as a systematic tool of genome analysis are examined.
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Affiliation(s)
- R Balling
- German Research Centre for Biotechnology, D-38124 Braunschweig, Germany.
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Abstract
A complete list of molecular components for immune system function is now available with the completion of the human and mouse genome sequences. However, identification and functional annotation of genes involved in immunological processes require a discovery methodology that can efficiently and broadly analyze the complex interplay of these components in vivo. Our recent experience indicates that genome-wide chemical mutagenesis in the mouse is an extremely powerful methodology for the identification of genes required for complex immunological processes.
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Affiliation(s)
- K A Nelms
- Australian Cancer Research Foundation Genetics Laboratory, Medical Genome Centre, John Curtin School of Medical Research, Canberra ACT 2601, Australia
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46
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Balling R, Hrabé de Angelis M. From developmental biology to developmental toxicology. Ann N Y Acad Sci 2001; 919:239-45. [PMID: 11083114 DOI: 10.1111/j.1749-6632.2000.tb06884.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Progress derived from the human genome project will have tremendous impact on toxicology. Questions concerning genetic susceptibility or resistance to toxic compound exposure and the dissection of the molecular mechanisms involved will be at the forefront of future toxicological research. In recent years, it was recognized that many of the molecular control mechanisms of embryogenesis have been conserved during evolution. The relevance of these observations for toxicology and the application of genetic approaches using mouse mutants as a tool for functional genome analysis are discussed.
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Affiliation(s)
- R Balling
- Institute of Mammalian Genetics, GSF-Research Center for Environment and Health, Neuherberg, Germany.
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Roix JJ, Hagge-Greenberg A, Bissonnette DM, Rodick S, Russell LB, O'Brien TP. Molecular and functional mapping of the piebald deletion complex on mouse chromosome 14. Genetics 2001; 157:803-15. [PMID: 11156998 PMCID: PMC1461538 DOI: 10.1093/genetics/157.2.803] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The piebald deletion complex is a set of overlapping chromosomal deficiencies surrounding the endothelin receptor B locus collected during the Oak Ridge specific-locus-test mutagenesis screen. These chromosomal deletions represent an important resource for genetic studies to dissect the functional content of a genomic region, and several developmental defects have been associated with mice homozygous for distinct piebald deletion alleles. We have used molecular markers to order the breakpoints for 20 deletion alleles that span a 15.7-18-cM region of distal mouse chromosome 14. Large deletions covering as much as 11 cM have been identified that will be useful for regionally directed mutagenesis screens to reveal recessive mutations that disrupt development. Deletions identified as having breakpoints positioned within previously described critical regions have been used in complementation studies to further define the functional intervals associated with the developmental defects. This has focused our efforts to isolate genes required for newborn respiration and survival, skeletal patterning and morphogenesis, and central nervous system development.
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Affiliation(s)
- J J Roix
- The Jackson Laboratory, 600 Main St., Bar Harbor, ME 04609, USA
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48
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Aponte JL, Sega GA, Hauser LJ, Dhar MS, Withrow CM, Carpenter DA, Rinchik EM, Culiat CT, Johnson DK. Point mutations in the murine fumarylacetoacetate hydrolase gene: Animal models for the human genetic disorder hereditary tyrosinemia type 1. Proc Natl Acad Sci U S A 2001; 98:641-5. [PMID: 11209059 PMCID: PMC14641 DOI: 10.1073/pnas.98.2.641] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/1999] [Accepted: 11/21/2000] [Indexed: 11/18/2022] Open
Abstract
Hereditary tyrosinemia type 1 (HT1) is a severe autosomal recessive metabolic disease associated with point mutations in the human fumarylacetoacetate hydrolase (FAH) gene that disrupt tyrosine catabolism. An acute form of HT1 results in death during the first months of life because of hepatic failure, whereas a chronic form leads to gradual development of liver disease often accompanied by renal dysfunction, childhood rickets, neurological crisis, and hepatocellular carcinoma. Mice homozygous for certain chromosome 7 deletions of the albino Tyr; c locus that also include Fah die perinatally as a result of liver dysfunction and exhibit a complex syndrome characterized by structural abnormalities and alterations in gene expression in the liver and kidney. Here we report that two independent, postnatally lethal mutations induced by N-ethyl-N-nitrosourea and mapped near Tyr are alleles of Fah. The Fah(6287SB) allele is a missense mutation in exon 6, and Fah(5961SB) is a splice mutation causing loss of exon 7, a subsequent frameshift in the resulting mRNA, and a severe reduction of Fah mRNA levels. Increased levels of the diagnostic metabolite succinylacetone in the urine of the Fah(6287SB) and Fah(5961SB) mutants indicate that these mutations cause a decrease in Fah enzymatic activity. Thus, the neonatal phenotype present in both mutants is due to a deficiency in Fah caused by a point mutation, and we propose Fah(5961SB) and Fah(6287SB) as mouse models for acute and chronic forms of human HT1, respectively.
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MESH Headings
- Acute Disease
- Alleles
- Amino Acid Substitution
- Animals
- Animals, Newborn
- Base Sequence
- Biomarkers
- Chronic Disease
- Crosses, Genetic
- DNA, Complementary/genetics
- Enzyme Induction
- Ethylnitrosourea
- Exons/genetics
- Female
- Frameshift Mutation
- Genes
- Genes, Lethal
- Heptanoates/urine
- Humans
- Hydrolases/deficiency
- Hydrolases/genetics
- Kidney/enzymology
- Liver/enzymology
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Models, Animal
- Molecular Sequence Data
- Mutagenesis
- Mutation, Missense
- Point Mutation
- RNA Splicing/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Tyrosinemias/enzymology
- Tyrosinemias/genetics
- Tyrosinemias/urine
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Affiliation(s)
- J L Aponte
- Division of Biology, University of Tennessee, Knoxville, TN 37996-0910, USA
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Hasson T, Walsh J, Cable J, Mooseker MS, Brown SD, Steel KP. Effects of shaker-1 mutations on myosin-VIIa protein and mRNA expression. CELL MOTILITY AND THE CYTOSKELETON 2000; 37:127-38. [PMID: 9186010 DOI: 10.1002/(sici)1097-0169(1997)37:2<127::aid-cm5>3.0.co;2-5] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Numerous mammalian diseases have been found to be due to mutations in components of the actin cytoskeleton. Recently, mutations in the gene for an unconventional myosin, myosin-VIIa, were found to be the basis for the deafness and vestibular dysfunction observed in shaker-1 (sh1) mice and for a human deafness-blindness syndrome, Usher syndrome type 1B. Seven alleles of sh1 mice were analyzed to assess the affects of different myosin-VIIa mutations on both gene expression and tissue function. Myosin-VIIa is expressed in the inner ear and the retina, as well as the kidney, lung, and testis. Northern blot analysis indicated that myosin-VIIa mRNA expression, size, and stability were unaffected in the seven sh1 alleles. Immunoblot analysis showed that all seven alleles expressed some full-length myosin-VIIa protein. The range of expression, however, ran from sh1 [original], which expressed wild-type levels of protein, to two strains, sh1(4494SB) and sh1(4626SB), which expressed less than 1% of the normal level of myosin-VIIa protein. For the three alleles of sh1 that have been characterized and that have mutations in the motor domain, sh1 [original], sh1(816SB) and sh1(6J), the level of protein expression observed in these sh1 alleles correlated well with the predicted effects of the mutations on motor function. No change in retinal or testicular structure was observed at the light microscopic level during the life span of the seven sh1 alleles. Myosin-VIIa protein, when detectable, was observed to locate properly in the sh1 mice. On the basis of these results, we propose that the mutations in myosin-VIIa in the sh1 alleles leads to both motor dysfunction and to a protein destabilization phenotype.
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Affiliation(s)
- T Hasson
- Department of Biology, Yale University, New Haven, Connecticut 06520, USA.
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50
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