151
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Vitelli F, Lindsay EA, Baldini A. Genetic dissection of the DiGeorge syndrome phenotype. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2003; 67:327-32. [PMID: 12858556 DOI: 10.1101/sqb.2002.67.327] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- F Vitelli
- Department of Pediatrics (Cardiology), Baylor College of Medicine, Houston, Texas 77030, USA
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152
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Xiao HD, Fuchs S, Frenzel K, Cole JM, Bernstein KE. Newer approaches to genetic modeling in mice: tissue-specific protein expression as studied using angiotensin-converting enzyme (ACE). THE AMERICAN JOURNAL OF PATHOLOGY 2003; 163:807-17. [PMID: 12937122 PMCID: PMC1868276 DOI: 10.1016/s0002-9440(10)63441-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Hong D Xiao
- Department of Pathology, Emory University, Atlanta, GA 30322, USA
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153
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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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154
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Kaczmarczyk SJ, Green JE. Induction of cre recombinase activity using modified androgen receptor ligand binding domains: a sensitive assay for ligand-receptor interactions. Nucleic Acids Res 2003; 31:e86. [PMID: 12888538 PMCID: PMC169976 DOI: 10.1093/nar/gng087] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Novel systems of inducible gene expression are presented in which CRE-M, an altered form of cre recombinase (cre), is fused to and activated by ligand binding to two forms of the androgen receptor (AR) ligand binding domain (LBD). Selective activation or inactivation of gene transcription is induced upon the addition of appropriate ligand. The coupling of this cre-LBD system with our previously reported highly sensitive assay to measure cre activity in vitro using a dual fluorescent gene switch reporter provides a novel, high-throughput assay system for identifying compounds that bind to and activate various forms of the LBD of androgen receptor. This method can similarly be applied to screen compounds for their activating properties on other steroid hormone LBDs. Three different forms of the AR-LBD were fused to CRE-M, including the wild-type AR-LBD (wt), a non-ligand binding truncated form, LBD (T), and a mutated form (Thr-->Ala substitution) identified in the LNCaP prostate cancer cell line, LBD (LNCaP). We demonstrate a 10-fold induction of cre activity by the addition of androgen agonists to the CRE-M-AR-LBD(wt) fusion protein, but not in the presence of the anti-androgen, flutamide. However, cre activity can be induced by flutamide with the CRE-M-AR-LBD(LNCaP) fusion protein. Similar activation properties were obtained when these fusion proteins were expressed using adenoviral vectors. When combined with our previously reported cre-lox gene switch system, the CRE-M-AR-LBD system can be utilized in gene therapy systems in which a therapeutic product may be initially expressed, replaced by a second product, or turned-off following exposure to ligand. This provides an important, additional level of regulation to gene therapy systems.
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Affiliation(s)
- Stanislaw J Kaczmarczyk
- Transgenic Oncogenesis Group, Laboratory of Cell Regulation and Carcinogenesis, National Cancer Institute, Bethesda, MD 20892, USA
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155
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Hadjantonakis AK, Dickinson ME, Fraser SE, Papaioannou VE. Technicolour transgenics: imaging tools for functional genomics in the mouse. Nat Rev Genet 2003; 4:613-25. [PMID: 12897773 DOI: 10.1038/nrg1126] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the past decade, a battery of powerful tools that encompass forward and reverse genetic approaches have been developed to dissect the molecular and cellular processes that regulate development and disease. The advent of genetically-encoded fluorescent proteins that are expressed in wild type and mutant mice, together with advances in imaging technology, make it possible to study these biological processes in many dimensions. Importantly, these technologies allow direct visual access to complex events as they happen in their native environment, which provides greater insights into mammalian biology than ever before.
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Affiliation(s)
- Anna-Katerina Hadjantonakis
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York 10032, USA
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156
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Abstract
The prospect of specifically controlling gene activities in vivo has become a defining hallmark of many model organisms of biological research. Where once the aim was to gain control over gene activities using endogenous control elements, new technologies have emerged that owe their remarkable specificity to heterologous components derived from evolutionarily distant species. This review highlights inducible transcriptional systems and site-specific recombination. Their quantitative and qualitative characteristics are discussed, with examples of how recent developments have expanded the spectrum of cells and organisms that are now accessible to genetic dissection of unprecedented precision. Transgenesis has already converted the mouse into a prime model for mammalian genetics. Combined with the new approaches of conditional activation or inactivation of genes, this model has opened up new horizons for the analysis of gene function in mammals.
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Affiliation(s)
- Manfred Gossen
- Max Delbrück Centrum, Robert-Rössle-Strasse 10, D-13125 Berlin, Germany.
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157
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Puente XS, Sánchez LM, Overall CM, López-Otín C. Human and mouse proteases: a comparative genomic approach. Nat Rev Genet 2003; 4:544-58. [PMID: 12838346 DOI: 10.1038/nrg1111] [Citation(s) in RCA: 639] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The availability of the human and mouse genome sequences has allowed the identification and comparison of their respective degradomes--the complete repertoire of proteases that are produced by these organisms. Because of the essential roles of proteolytic enzymes in the control of cell behaviour, survival and death, degradome analysis provides a useful framework for the global exploration of these protease-mediated functions in normal and pathological conditions.
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Affiliation(s)
- Xose S Puente
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología, Universidad de Oviedo, 33006 Oviedo, Spain
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158
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Kiehn O, Butt SJB. Physiological, anatomical and genetic identification of CPG neurons in the developing mammalian spinal cord. Prog Neurobiol 2003; 70:347-61. [PMID: 12963092 DOI: 10.1016/s0301-0082(03)00091-1] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The basic motor patterns underlying rhythmic limb movements during locomotion are generated by neuronal networks located within the spinal cord. These networks are called Central Pattern Generators (CPGs). Isolated spinal cord preparations from newborn rats and mice have become increasingly important for understanding the organization of the CPG in the mammalian spinal cord. Early studies using these preparations have focused on the overall network structure and the localization of the CPG. In this review we concentrate on recent experiments aimed at identifying and characterizing CPG-interneurons in the rodent. These experiments include the organization and function of descending commissural interneurons (dCINs) in the hindlimb CPG of the neonatal rat, as well as the role of Ephrin receptor A4 (EphA4) and its Ephrin ligand B3 (EphrinB3), in the construction of the mammalian locomotor network. These latter experiments have defined EphA4 as a molecular marker for mammalian excitatory hindlimb CPG neurons. We also review genetic approaches that can be applied to the mouse spinal cord. These include methods for identifying sub-populations of neurons by genetically encoded reporters, techniques to trace network connectivity with cell-specific genetically encoded tracers, and ways to selectively ablate or eliminate neuron populations from the CPG. We propose that by applying a multidisciplinary approach it will be possible to understand the network structure of the mammalian locomotor CPG. Such an understanding will be instrumental in devising new therapeutic strategies for patients with spinal cord injury.
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Affiliation(s)
- Ole Kiehn
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden.
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159
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Butt SJB, Kiehn O. Functional identification of interneurons responsible for left-right coordination of hindlimbs in mammals. Neuron 2003; 38:953-63. [PMID: 12818180 DOI: 10.1016/s0896-6273(03)00353-2] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Local neuronal networks that are responsible for walking are poorly characterized in mammals. Using an innovative approach to identify interneuron inputs onto motorneuron populations in a neonatal rodent spinal cord preparation, we have investigated the network responsible for left-right coordination of the hindlimbs. We demonstrate how commissural interneurons (CINs), whose axons traverse the midline to innervate contralateral neurons, are organized such that distinct flexor and extensor centers in the rostral lumbar spinal cord define activity in both flexor and extensor caudal motor pools. In addition, the nature of some connections are reconfigured on switching from rest to locomotion via a mechanism that might be associated with synaptic plasticity in the spinal cord. These results from identified pattern-generating interneurons demonstrate how interneuron populations create an effective network to underlie behavior in mammals.
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Affiliation(s)
- Simon J B Butt
- Mammalian Locomotor Laboratory, Department of Neuroscience, Karolinska Institutet, Retzius väg 8, 171 77, Stockholm, Sweden
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160
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Martin SS, Chu VC, Baldwin E. Modulation of the active complex assembly and turnover rate by protein-DNA interactions in Cre-LoxP recombination. Biochemistry 2003; 42:6814-26. [PMID: 12779336 PMCID: PMC2885442 DOI: 10.1021/bi0272306] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cre promotes recombination at the 34 bp LoxP sequence. Substitution of a critical C-G base pair in LoxP with an A-T base pair, to give LoxAT, reduced Cre binding in vitro and abolished recombination in vivo [Hartung, M., and Kisters-Woike, B. (1998) J. Biol. Chem. 273, 22884-22891].We demonstrated that LoxAT can be recombined in vitro. However, Cre discriminates against this substrate both before and after DNA binding. The preference for LoxP over LoxAT is the result of reduced binding and a slower turnover rate, amplified by changes in cooperativity of complex assembly. With LoxAT, similar levels of substrate turnover required 2-2.5-fold higher protein-DNA concentrations compared to LoxP, but the sigmoidal behavior of the concentration dependence was more pronounced. Further, the Cre-LoxAT complexes reacted 4-5-fold more slowly. In the 2.3 A resolution Cre-LoxAT complex structure, the major groove Arg259-guanine interaction was disrupted, explaining the reduced binding. Overall structural shifts and mobility changes indicate more favorable interactions between subunits, providing a hypothesis for the reduced turnover rate. Concomitant with the displacement of Arg259 from the DNA, adjacent charged residues Glu262 and Glu266 shifted to form salt bridges with the Arg259 guanidinium moiety. Substitution of Glu262 and Glu266 with glutamine increased Cre complex assembly efficiency and reaction rates with both LoxAT and LoxP, but diminished Cre's ability to distinguish them. The increased rate of this variant suggests that DNA substrate binding and turnover are coupled. The improved efficiency, made at some expense of sequence discrimination, may be useful for enhancing recombination in vivo.
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Affiliation(s)
- Shelley S. Martin
- Section of Molecular and Cellular Biology, University of California, 1 Shields Avenue, Davis, California 95616
| | - Victor C. Chu
- Section of Molecular and Cellular Biology, University of California, 1 Shields Avenue, Davis, California 95616
| | - Enoch Baldwin
- Section of Molecular and Cellular Biology, University of California, 1 Shields Avenue, Davis, California 95616
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, California 95616
- To whom correspondence should be addressed. . Phone: (530) 752-1108. Fax: (530) 752-3085
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161
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Delmas V, Martinozzi S, Bourgeois Y, Holzenberger M, Larue L. Cre-mediated recombination in the skin melanocyte lineage. Genesis 2003; 36:73-80. [PMID: 12820167 DOI: 10.1002/gene.10197] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Organ-specific expression of a Cre recombinase allows the analysis of gene function in a particular tissue or cell type. Using a 6.1 kb promoter from the mouse tyrosinase gene, we generated and characterized two lines of transgenic mice that express Cre recombinase in melanoblasts. Utilizing a Cre-responsive reporter mouse strain, genetic recombination was detected in the melanoblasts of the skin from embryonic day 11.5. In addition, Cre-expression was detected in the skin and eyes of mice. Cre transgene activity was occasionally detected in the brain and peripheral nerves but not in other tissues. When Tyr::Cre mice were crossed with mice carrying a homozygous loxP conditional mutation for the insulin-like growth factor receptor gene (Igf1r), Cre-melanoblast-specific recombination pattern was confirmed and no abnormal phenotype was observed. In conclusion, Tyr::Cre transgenic mice provide a valuable tool to follow the cell lineage and to examine gene function in melanocyte development and transformation.
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162
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Walz K, Caratini-Rivera S, Bi W, Fonseca P, Mansouri DL, Lynch J, Vogel H, Noebels JL, Bradley A, Lupski JR. Modeling del(17)(p11.2p11.2) and dup(17)(p11.2p11.2) contiguous gene syndromes by chromosome engineering in mice: phenotypic consequences of gene dosage imbalance. Mol Cell Biol 2003; 23:3646-55. [PMID: 12724422 PMCID: PMC154242 DOI: 10.1128/mcb.23.10.3646-3655.2003] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Contiguous gene syndromes (CGS) are a group of disorders associated with chromosomal rearrangements of which the phenotype is thought to result from altered copy numbers of physically linked dosage-sensitive genes. Smith-Magenis syndrome (SMS) is a CGS associated with a deletion within band p11.2 of chromosome 17. Recently, patients harboring the predicted reciprocal duplication product [dup(17)(p11.2p11.2)] have been described as having a relatively mild phenotype. By chromosomal engineering, we created rearranged chromosomes carrying the deletion [Df(11)17] or duplication [Dp(11)17] of the syntenic region on mouse chromosome 11 that spans the genomic interval commonly deleted in SMS patients. Df(11)17/+ mice exhibit craniofacial abnormalities, seizures, marked obesity, and male-specific reduced fertility. Dp(11)17/+ animals are underweight and do not have seizures, craniofacial abnormalities, or reduced fertility. Examination of Df(11)17/Dp(11)17 animals suggests that most of the observed phenotypes result from gene dosage effects. Our murine models represent a powerful tool to analyze the consequences of gene dosage imbalance in this genomic interval and to investigate the molecular genetic bases of both SMS and dup(17)(p11.2p11.2).
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Affiliation(s)
- Katherina Walz
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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163
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Abstract
Autoimmune diseases are, in general, under complex genetic control and subject to strong interactions between genetics and the environment. Greater knowledge of the underlying genetics will provide immunologists with a framework for study of the immune dysregulation that occurs in such diseases. Ascertaining the number of genes that are involved and their characterization have, however, proven to be difficult. Improved methods of genetic analysis and the availability of a draft sequence of the complete mouse genome have markedly improved the outlook for such research, and they have emphasized the advantages of mice as a model system. In this review, we provide an overview of the genetic analysis of autoimmune diseases and of the crucial role of congenic and consomic mouse strains in such research.
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Affiliation(s)
- Ute C Rogner
- Institut Pasteur, Unité Génétique Moléculaire Murine, 25 rue du Docteur Roux, 75015 Paris, France
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164
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Kearney JB, Bautch VL. In Vitro Differentiation of Mouse ES Cells: Hematopoietic and Vascular Development. Methods Enzymol 2003; 365:83-98. [PMID: 14696339 DOI: 10.1016/s0076-6879(03)65006-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Joseph B Kearney
- Program in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, CB#3280, Chapel Hill, North Carolina 27599, USA
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165
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Abstract
Genomic rearrangements play a major role in the pathogenesis of human genetic diseases. Nonallelic homologous recombination (NAHR) between low-copy repeats (LCRs) that flank unique genomic segments results in changes of genome organization and can cause a loss or gain of genomic segments. These LCRs appear to have arisen recently during primate speciation via paralogous segmental duplication, thus making the human species particularly susceptible to genomic rearrangements. Genomic disorders are defined as a group of diseases that result from genomic rearrangements, mostly mediated by NAHR. Molecular investigations of genomic disorders have revealed genome architectural features associated with susceptibility to rearrangements and the recombination mechanisms responsible for such rearrangements. The human genome sequence project reveals that LCRs may account for 5% of the genome, suggesting that many novel genomic disorders might still remain to be recognized.
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Affiliation(s)
- Ken Inoue
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.
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166
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Waterston RH, Lindblad-Toh K, Birney E, Rogers J, Abril JF, Agarwal P, Agarwala R, Ainscough R, Alexandersson M, An P, Antonarakis SE, Attwood J, Baertsch R, Bailey J, Barlow K, Beck S, Berry E, Birren B, Bloom T, Bork P, Botcherby M, Bray N, Brent MR, Brown DG, Brown SD, Bult C, Burton J, Butler J, Campbell RD, Carninci P, Cawley S, Chiaromonte F, Chinwalla AT, Church DM, Clamp M, Clee C, Collins FS, Cook LL, Copley RR, Coulson A, Couronne O, Cuff J, Curwen V, Cutts T, Daly M, David R, Davies J, Delehaunty KD, Deri J, Dermitzakis ET, Dewey C, Dickens NJ, Diekhans M, Dodge S, Dubchak I, Dunn DM, Eddy SR, Elnitski L, Emes RD, Eswara P, Eyras E, Felsenfeld A, Fewell GA, Flicek P, Foley K, Frankel WN, Fulton LA, Fulton RS, Furey TS, Gage D, Gibbs RA, Glusman G, Gnerre S, Goldman N, Goodstadt L, Grafham D, Graves TA, Green ED, Gregory S, Guigó R, Guyer M, Hardison RC, Haussler D, Hayashizaki Y, Hillier LW, Hinrichs A, Hlavina W, Holzer T, Hsu F, Hua A, Hubbard T, Hunt A, Jackson I, Jaffe DB, Johnson LS, Jones M, Jones TA, Joy A, Kamal M, Karlsson EK, Karolchik D, Kasprzyk A, Kawai J, Keibler E, Kells C, Kent WJ, Kirby A, Kolbe DL, Korf I, Kucherlapati RS, Kulbokas EJ, Kulp D, Landers T, Leger JP, Leonard S, Letunic I, Levine R, Li J, Li M, Lloyd C, Lucas S, Ma B, Maglott DR, Mardis ER, Matthews L, Mauceli E, Mayer JH, McCarthy M, McCombie WR, McLaren S, McLay K, McPherson JD, Meldrim J, Meredith B, Mesirov JP, Miller W, Miner TL, Mongin E, Montgomery KT, Morgan M, Mott R, Mullikin JC, Muzny DM, Nash WE, Nelson JO, Nhan MN, Nicol R, Ning Z, Nusbaum C, O'Connor MJ, Okazaki Y, Oliver K, Overton-Larty E, Pachter L, Parra G, Pepin KH, Peterson J, Pevzner P, Plumb R, Pohl CS, Poliakov A, Ponce TC, Ponting CP, Potter S, Quail M, Reymond A, Roe BA, Roskin KM, Rubin EM, Rust AG, Santos R, Sapojnikov V, Schultz B, Schultz J, Schwartz MS, Schwartz S, Scott C, Seaman S, Searle S, Sharpe T, Sheridan A, Shownkeen R, Sims S, Singer JB, Slater G, Smit A, Smith DR, Spencer B, Stabenau A, Stange-Thomann N, Sugnet C, Suyama M, Tesler G, Thompson J, Torrents D, Trevaskis E, Tromp J, Ucla C, Ureta-Vidal A, Vinson JP, Von Niederhausern AC, Wade CM, Wall M, Weber RJ, Weiss RB, Wendl MC, West AP, Wetterstrand K, Wheeler R, Whelan S, Wierzbowski J, Willey D, Williams S, Wilson RK, Winter E, Worley KC, Wyman D, Yang S, Yang SP, Zdobnov EM, Zody MC, Lander ES. Initial sequencing and comparative analysis of the mouse genome. Nature 2002; 420:520-62. [PMID: 12466850 DOI: 10.1038/nature01262] [Citation(s) in RCA: 4823] [Impact Index Per Article: 219.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2002] [Accepted: 10/31/2002] [Indexed: 12/18/2022]
Abstract
The sequence of the mouse genome is a key informational tool for understanding the contents of the human genome and a key experimental tool for biomedical research. Here, we report the results of an international collaboration to produce a high-quality draft sequence of the mouse genome. We also present an initial comparative analysis of the mouse and human genomes, describing some of the insights that can be gleaned from the two sequences. We discuss topics including the analysis of the evolutionary forces shaping the size, structure and sequence of the genomes; the conservation of large-scale synteny across most of the genomes; the much lower extent of sequence orthology covering less than half of the genomes; the proportions of the genomes under selection; the number of protein-coding genes; the expansion of gene families related to reproduction and immunity; the evolution of proteins; and the identification of intraspecies polymorphism.
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MESH Headings
- Animals
- Base Composition
- Chromosomes, Mammalian/genetics
- Conserved Sequence/genetics
- CpG Islands/genetics
- Evolution, Molecular
- Gene Expression Regulation
- Genes/genetics
- Genetic Variation/genetics
- Genome
- Genome, Human
- Genomics
- Humans
- Mice/classification
- Mice/genetics
- Mice, Knockout
- Mice, Transgenic
- Models, Animal
- Multigene Family/genetics
- Mutagenesis
- Neoplasms/genetics
- Physical Chromosome Mapping
- Proteome/genetics
- Pseudogenes/genetics
- Quantitative Trait Loci/genetics
- RNA, Untranslated/genetics
- Repetitive Sequences, Nucleic Acid/genetics
- Selection, Genetic
- Sequence Analysis, DNA
- Sex Chromosomes/genetics
- Species Specificity
- Synteny
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167
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Bockamp E, Maringer M, Spangenberg C, Fees S, Fraser S, Eshkind L, Oesch F, Zabel B. Of mice and models: improved animal models for biomedical research. Physiol Genomics 2002; 11:115-32. [PMID: 12464688 DOI: 10.1152/physiolgenomics.00067.2002] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The ability to engineer the mouse genome has profoundly transformed biomedical research. During the last decade, conventional transgenic and gene knockout technologies have become invaluable experimental tools for modeling genetic disorders, assigning functions to genes, evaluating drugs and toxins, and by and large helping to answer fundamental questions in basic and applied research. In addition, the growing demand for more sophisticated murine models has also become increasingly evident. Good state-of-principle knowledge about the enormous potential of second-generation conditional mouse technology will be beneficial for any researcher interested in using these experimental tools. In this review we will focus on practice, pivotal principles, and progress in the rapidly expanding area of conditional mouse technology. The review will also present an internet compilation of available tetracycline-inducible mouse models as tools for biomedical research (http://www.zmg.uni-mainz.de/tetmouse/).
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Affiliation(s)
- Ernesto Bockamp
- Laboratory of Molecular Mouse Genetics, Institute of Toxicology, Johannes Gutenberg-University Mainz, D-55131 Mainz, Germany.
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168
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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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169
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170
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Schaller E, Macfarlane AJ, Rupec RA, Gordon S, McKnight AJ, Pfeffer K. Inactivation of the F4/80 glycoprotein in the mouse germ line. Mol Cell Biol 2002; 22:8035-43. [PMID: 12391169 PMCID: PMC134735 DOI: 10.1128/mcb.22.22.8035-8043.2002] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Macrophages play a crucial role in the defense against pathogens. Distinct macrophage populations can be defined by the expression of restricted cell surface proteins. Resident tissue macrophages, encompassing Kupffer cells of the liver and red pulp macrophages of the spleen, characteristically express the F4/80 molecule, a cell surface glycoprotein related to the seven transmembrane-spanning family of hormone receptors. In this study, gene targeting was used to simultaneously inactivate the F4/80 molecule in the germ line of the mouse and to produce a mouse line that expresses the Cre recombinase under the direct control of the F4/80 promoter (F4/80-Cre knock-in). F4/80-deficient mice are healthy and fertile. Macrophage populations in tissues can develop in the absence of F4/80 expression. Functional analysis revealed that the generation of T-cell-independent B-cell responses and macrophage antimicrobial defense after infection with Listeria monocytogenes are not impaired in the absence of F4/80. Interestingly, tissues of F4/80-deficient mice could not be labeled with anti-BM8, another macrophage subset-specific marker with hitherto undefined molecular antigenic structure. Recombinant expression of a F4/80 cDNA in heterologous cells confirmed this observation, indicating that the targets recognized by the F4/80 and BM8 monoclonal antibodies are identical.
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Affiliation(s)
- Evelyne Schaller
- Institute of Medical Microbiology, Immunology and Hygiene, Technical University of Munich, D-81675 Munich, Germany
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171
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Koval M. Sharing signals: connecting lung epithelial cells with gap junction channels. Am J Physiol Lung Cell Mol Physiol 2002; 283:L875-93. [PMID: 12376339 DOI: 10.1152/ajplung.00078.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gap junction channels enable the direct flow of signaling molecules and metabolites between cells. Alveolar epithelial cells show great variability in the expression of gap junction proteins (connexins) as a function of cell phenotype and cell state. Differential connexin expression and control by alveolar epithelial cells have the potential to enable these cells to regulate the extent of intercellular coupling in response to cell stress and to regulate surfactant secretion. However, defining the precise signals transmitted through gap junction channels and the cross talk between gap junctions and other signaling pathways has proven difficult. Insights from what is known about roles for gap junctions in other systems in the context of the connexin expression pattern by lung cells can be used to predict potential roles for gap junctional communication between alveolar epithelial cells.
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Affiliation(s)
- Michael Koval
- Department of Physiology and Institute for Environmental Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
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172
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Rijnkels M. Multispecies comparison of the casein gene loci and evolution of casein gene family. J Mammary Gland Biol Neoplasia 2002; 7:327-45. [PMID: 12751895 DOI: 10.1023/a:1022808918013] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Caseins, the major milk proteins, are present in a genomic cluster spanning 250-350 kb. The divergence at the coding level between human, rodent, and cattle sequences is rather extensive for most of the genes in this region. Nevertheless, comparative analysis of genomic sequences harboring the casein gene cluster region of these species (with equal evolutionary distances 79-88 Myr) shows that the organization and orientation of the genes is highly conserved. The conserved gene structure indicates that the molecular diversity of the casein genes is achieved through variable use of exons in different species and high evolutionary divergence. Comparative analysis also revealed the presence within two species of uncharacterized casein family members and ruled out the previously held notion that another gene family, located in this region, is primate-specific. Several other new genes as well as conserved noncoding sequences with potential regulatory functions were identified. All genes identified in this region are, or are predicted to be, secreted proteins involved in mineral homeostasis, nutrition, and/or host defense, and are mostly expressed in the mammary and/or salivary glands. These observations suggest a possible common ancestry for the genes in this region.
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Affiliation(s)
- Monique Rijnkels
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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173
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Abstract
Cre is a DNA recombinase that recognizes 34 base-pair loxP sites of recombination. We have developed a cell-permeable Cre recombinase, TATCre, that is capable of mediating deletion of loxP-flanked targets by simply adding TATCre to cell cultures. Thus, TATCre allows efficient induced DNA recombination without the use of a Cre recombinase transgene or any other genetic material and should prove useful for the genetic manipulation of a wide variety of cell types that have been engineered to possess loxP sites.
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Affiliation(s)
- Sunil K Joshi
- Institute of Molecular Medicine & Genetics and Department of Medicine, Medical College of Georgia, Augusta 30912, USA
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174
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McDermid HE, Morrow BE. Genomic disorders on 22q11. Am J Hum Genet 2002; 70:1077-88. [PMID: 11925570 PMCID: PMC447586 DOI: 10.1086/340363] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2002] [Accepted: 02/18/2002] [Indexed: 11/03/2022] Open
Abstract
The 22q11 region is involved in chromosomal rearrangements that lead to altered gene dosage, resulting in genomic disorders that are characterized by mental retardation and/or congenital malformations. Three such disorders-cat-eye syndrome (CES), der(22) syndrome, and velocardiofacial syndrome/DiGeorge syndrome (VCFS/DGS)-are associated with four, three, and one dose, respectively, of parts of 22q11. The critical region for CES lies centromeric to the deletion region of VCFS/DGS, although, in some cases, the extra material in CES extends across the VCFS/DGS region. The der(22) syndrome region overlaps both the CES region and the VCFS/DGS region. Molecular approaches have revealed a set of common chromosome breakpoints that are shared between the three disorders, implicating specific mechanisms that cause these rearrangements. Most VCFS/DGS and CES rearrangements are likely to occur by homologous recombination events between blocks of low-copy repeats (e.g., LCR22), whereas nonhomologous recombination mechanisms lead to the constitutional t(11;22) translocation. Meiotic nondisjunction events in carriers of the t(11;22) translocation can then lead to offspring with der(22) syndrome. The molecular basis of the clinical phenotype of these genomic disorders has also begun to be addressed. Analysis of both the genomic sequence for the 22q11 interval and the orthologous regions in the mouse has identified >24 genes that are shared between VCFS/DGS and der(22) syndrome and has identified 14 putative genes that are shared between CES and der(22) syndrome. The ability to manipulate the mouse genome aids in the identification of candidate genes in these three syndromes. Research on genomic disorders on 22q11 will continue to expand our knowledge of the mechanisms of chromosomal rearrangements and the molecular basis of their phenotypic consequences.
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Affiliation(s)
- Heather E. McDermid
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta; and Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, NY
| | - Bernice E. Morrow
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta; and Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, NY
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175
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Kwan KM. Conditional alleles in mice: practical considerations for tissue-specific knockouts. Genesis 2002; 32:49-62. [PMID: 11857777 DOI: 10.1002/gene.10068] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kin-Ming Kwan
- Department of Molecular Genetics, University of Texas, M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
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176
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Abstract
Identifying the genes that underlie the pathogenesis of chromosome deletion and duplication syndromes is a challenge because the affected chromosomal segment can contain many genes. The identification of genes that are relevant to these disorders often requires the analysis of individuals that carry rare, small deletions, translocations or single-gene mutations. Research into the chromosome 22 deletion (del22q11) syndrome, which encompasses DiGeorge and velocardiofacial syndrome, has taken a different path in recent years, using mouse models to circumvent the paucity of informative human material. These mouse models have provided new insights into the pathogenesis of del22q11 syndrome and have established strategies for research into chromosomal-deletion and -duplication syndromes.
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Affiliation(s)
- E A Lindsay
- Division of Cardiology, Department of Pediatrics, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas 77030, USA.
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177
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Alfred J. Breaking into imprinted regions. Nat Rev Genet 2001. [DOI: 10.1038/35093511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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