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McLellan MA, Rosenthal NA, Pinto AR. Cre-loxP-Mediated Recombination: General Principles and Experimental Considerations. ACTA ACUST UNITED AC 2017; 7:1-12. [DOI: 10.1002/cpmo.22] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Micheal A. McLellan
- The Jackson Laboratory; Bar Harbor Maine
- Graduate Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University; Boston Massachusetts
| | - Nadia A. Rosenthal
- The Jackson Laboratory; Bar Harbor Maine
- Australian Regenerative Medicine Institute, Monash University; Melbourne Victoria Australia
- National Heart and Lung Institute, Imperial College London; London United Kingdom
| | - Alexander R. Pinto
- The Jackson Laboratory; Bar Harbor Maine
- Australian Regenerative Medicine Institute, Monash University; Melbourne Victoria Australia
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52
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Barger SW. Gene regulation and genetics in neurochemistry, past to future. J Neurochem 2016; 139 Suppl 2:24-57. [PMID: 27747882 DOI: 10.1111/jnc.13629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 03/01/2016] [Accepted: 03/30/2016] [Indexed: 12/14/2022]
Abstract
Ask any neuroscientist to name the most profound discoveries in the field in the past 60 years, and at or near the top of the list will be a phenomenon or technique related to genes and their expression. Indeed, our understanding of genetics and gene regulation has ushered in whole new systems of knowledge and new empirical approaches, many of which could not have even been imagined prior to the molecular biology boon of recent decades. Neurochemistry, in the classic sense, intersects with these concepts in the manifestation of neuropeptides, obviously dependent upon the central dogma (the established rules by which DNA sequence is eventually converted into protein primary structure) not only for their conformation but also for their levels and locales of expression. But, expanding these considerations to non-peptide neurotransmitters illustrates how gene regulatory events impact neurochemistry in a much broader sense, extending beyond the neurochemicals that translate electrical signals into chemical ones in the synapse, to also include every aspect of neural development, structure, function, and pathology. From the beginning, the mutability - yet relative stability - of genes and their expression patterns were recognized as potential substrates for some of the most intriguing phenomena in neurobiology - those instances of plasticity required for learning and memory. Near-heretical speculation was offered in the idea that perhaps the very sequence of the genome was altered to encode memories. A fascinating component of the intervening progress includes evidence that the central dogma is not nearly as rigid and consistent as we once thought. And this mutability extends to the potential to manipulate that code for both experimental and clinical purposes. Astonishing progress has been made in the molecular biology of neurochemistry during the 60 years since this journal debuted. Many of the gains in conceptual understanding have been driven by methodological progress, from automated high-throughput sequencing instruments to recombinant-DNA vectors that can convey color-coded genetic modifications in the chromosomes of live adult animals. This review covers the highlights of these advances, both theoretical and technological, along with a brief window into the promising science ahead. This article is part of the 60th Anniversary special issue.
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Affiliation(s)
- Steven W Barger
- Department of Geriatrics, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA. .,Geriatric Research Education and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, USA.
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Kunii M, Ohara-Imaizumi M, Takahashi N, Kobayashi M, Kawakami R, Kondoh Y, Shimizu T, Simizu S, Lin B, Nunomura K, Aoyagi K, Ohno M, Ohmuraya M, Sato T, Yoshimura SI, Sato K, Harada R, Kim YJ, Osada H, Nemoto T, Kasai H, Kitamura T, Nagamatsu S, Harada A. Opposing roles for SNAP23 in secretion in exocrine and endocrine pancreatic cells. J Cell Biol 2016; 215:121-138. [PMID: 27697926 PMCID: PMC5057288 DOI: 10.1083/jcb.201604030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 08/26/2016] [Indexed: 12/17/2022] Open
Abstract
Kunii et al. reveal that the SNARE protein SNAP23 plays distinct roles in the secretion of amylase in exocrine cells and of insulin in endocrine cells the pancreas and show that MF286, a novel inhibitor of SNAP23, may be a new drug candidate for diabetes. The membrane fusion of secretory granules with plasma membranes is crucial for the exocytosis of hormones and enzymes. Secretion disorders can cause various diseases such as diabetes or pancreatitis. Synaptosomal-associated protein 23 (SNAP23), a soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor (SNARE) molecule, is essential for secretory granule fusion in several cell lines. However, the in vivo functions of SNAP23 in endocrine and exocrine tissues remain unclear. In this study, we show opposing roles for SNAP23 in secretion in pancreatic exocrine and endocrine cells. The loss of SNAP23 in the exocrine and endocrine pancreas resulted in decreased and increased fusion of granules to the plasma membrane after stimulation, respectively. Furthermore, we identified a low molecular weight compound, MF286, that binds specifically to SNAP23 and promotes insulin secretion in mice. Our results demonstrate opposing roles for SNAP23 in the secretion mechanisms of the endocrine and exocrine pancreas and reveal that the SNAP23-binding compound MF286 may be a promising drug for diabetes treatment.
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Affiliation(s)
- Masataka Kunii
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma 371-8512, Japan Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Mica Ohara-Imaizumi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo 181-8611, Japan
| | - Noriko Takahashi
- Laboratory of Structural Physiology, Graduate School of Medicine, Center for Disease Biology and Integrative Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Masaki Kobayashi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma 371-8512, Japan
| | - Ryosuke Kawakami
- Laboratory of Molecular and Cellular Biophysics, Research Institute for Electronic Science, Hokkaido University, Hokkaido 001-0020, Japan
| | - Yasumitsu Kondoh
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan
| | - Takeshi Shimizu
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan
| | - Siro Simizu
- Department of Applied Chemistry, Faculty of Science and Technology, Keio University, Kanagawa 223-8522, Japan
| | - Bangzhong Lin
- Drug Discovery Team, Office for University-Industry Collaboration Planning and Promotion, Osaka University, Osaka 565-0871, Japan
| | - Kazuto Nunomura
- Drug Discovery Team, Office for University-Industry Collaboration Planning and Promotion, Osaka University, Osaka 565-0871, Japan
| | - Kyota Aoyagi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo 181-8611, Japan
| | - Mitsuyo Ohno
- Laboratory of Structural Physiology, Graduate School of Medicine, Center for Disease Biology and Integrative Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Masaki Ohmuraya
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan
| | - Takashi Sato
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma 371-8512, Japan
| | - Shin-Ichiro Yoshimura
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Ken Sato
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma 371-8512, Japan
| | - Reiko Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan Department of Judo Therapy, Takarazuka University of Medical and Health Care, Hyogo 666-0152, Japan
| | - Yoon-Jeong Kim
- Drug Discovery Team, Office for University-Industry Collaboration Planning and Promotion, Osaka University, Osaka 565-0871, Japan
| | - Hiroyuki Osada
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan
| | - Tomomi Nemoto
- Laboratory of Molecular and Cellular Biophysics, Research Institute for Electronic Science, Hokkaido University, Hokkaido 001-0020, Japan
| | - Haruo Kasai
- Laboratory of Structural Physiology, Graduate School of Medicine, Center for Disease Biology and Integrative Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Tadahiro Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma 371-8512, Japan
| | - Shinya Nagamatsu
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo 181-8611, Japan
| | - Akihiro Harada
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma 371-8512, Japan Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
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"Cre/loxP plus BAC": a strategy for direct cloning of large DNA fragment and its applications in Photorhabdus luminescens and Agrobacterium tumefaciens. Sci Rep 2016; 6:29087. [PMID: 27364376 PMCID: PMC4929569 DOI: 10.1038/srep29087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/14/2016] [Indexed: 01/23/2023] Open
Abstract
Heterologous expression has been proven to be a valid strategy for elucidating the natural products produced by gene clusters uncovered by genome sequencing projects. Efforts have been made to efficiently clone gene clusters directly from genomic DNA and several approaches have been developed. Here, we present an alternative strategy based on the site-specific recombinase system Cre/loxP for direct cloning gene clusters. A type three secretion system (T3SS) gene cluster (~32 kb) from Photorhabdus luminescens TT01 and DNA fragment (~78 kb) containing the siderophore biosynthetic gene cluster from Agrobacterium tumefaciens C58 have been successfully cloned into pBeloBAC11 with “Cre/loxP plus BAC” strategy. Based on the fact that Cre/loxP system has successfully used for genomic engineering in a wide range of organisms, we believe that this strategy could be widely used for direct cloning of large DNA fragment.
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Ye Z, Sun L, Li R, Han M, Zhuang Y, Wu X, Xu T. Generation of a Mouse Full-length Balancer with Versatile Cassette-shuttling Selection Strategy. Int J Biol Sci 2016; 12:911-6. [PMID: 27489495 PMCID: PMC4971730 DOI: 10.7150/ijbs.15172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/20/2016] [Indexed: 11/22/2022] Open
Abstract
Balancer chromosomes are important tools for a variety of genetic manipulations in lower model organisms, owing to their ability to suppress recombination. In mouse, however, such effort has not been accomplished, mostly due to the size of the chromosomes and the complexity of multiple step chromosomal engineering. We developed an effective and versatile cassette-shuttling selection (CASS) strategy involving only two selection markers to achieve the sequential production of multiple large inversions along the chromosome. Using this strategy, we successfully generated the first full-length balancer in mice and showed that Balancer 17M-GFP can efficiently suppress recombination. Our study has not only generated a useful genetic resource, but also provided a strategy for constructing mammalian balancer chromosomes.
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Affiliation(s)
- Zhisheng Ye
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China
| | - Lei Sun
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China
| | - Rongbo Li
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China
| | - Min Han
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China.; 2. Howard Hughes Medical Institute, Department of Molecular, Cellular, Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Yuan Zhuang
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China.; 3. Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
| | - Xiaohui Wu
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China
| | - Tian Xu
- 1. State Key Laboratory of Genetic Engineering and National Center for International Research of Development and Disease, Collaborative Innovation Center for Genetics and Development, Fudan-Yale Biomedical Research Center, Institute of Developmental Biology and Molecular Medicine, Fudan University, Shanghai 200433, China.; 4. Howard Hughes Medical Institute, Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
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56
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Lake JI, Avetisyan M, Zimmermann AG, Heuckeroth RO. Neural crest requires Impdh2 for development of the enteric nervous system, great vessels, and craniofacial skeleton. Dev Biol 2015; 409:152-165. [PMID: 26546974 DOI: 10.1016/j.ydbio.2015.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 11/02/2015] [Accepted: 11/03/2015] [Indexed: 10/22/2022]
Abstract
Mutations that impair the proliferation of enteric neural crest-derived cells (ENCDC) cause Hirschsprung disease, a potentially lethal birth defect where the enteric nervous system (ENS) is absent from distal bowel. Inosine 5' monophosphate dehydrogenase (IMPDH) activity is essential for de novo GMP synthesis, and chemical inhibition of IMPDH induces Hirschsprung disease-like pathology in mouse models by reducing ENCDC proliferation. Two IMPDH isoforms are ubiquitously expressed in the embryo, but only IMPDH2 is required for life. To further understand the role of IMPDH2 in ENS and neural crest development, we characterized a conditional Impdh2 mutant mouse. Deletion of Impdh2 in the early neural crest using the Wnt1-Cre transgene produced defects in multiple neural crest derivatives including highly penetrant intestinal aganglionosis, agenesis of the craniofacial skeleton, and cardiac outflow tract and great vessel malformations. Analysis using a Rosa26 reporter mouse suggested that some or all of the remaining ENS in Impdh2 conditional-knockout animals was derived from cells that escaped Wnt1-Cre mediated DNA recombination. These data suggest that IMPDH2 mediated guanine nucleotide synthesis is essential for normal development of the ENS and other neural crest derivatives.
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Affiliation(s)
- Jonathan I Lake
- Department of Pediatrics and Department of Developmental Regenerative and Stem Cell Biology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8208, St. Louis, MO 63021, USA
| | - Marina Avetisyan
- Department of Pediatrics and Department of Developmental Regenerative and Stem Cell Biology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8208, St. Louis, MO 63021, USA
| | - Albert G Zimmermann
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 125 Mason Farm Rd, Chapel Hill, NC 27599, USA
| | - Robert O Heuckeroth
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania and The Children's Hospital of Philadelphia Research Institute, 3615 Civic Center Blvd, Philadelphia, PA 19104, USA.
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57
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Nelson RK, Gould KA. An Lck-cre transgene accelerates autoantibody production and lupus development in (NZB × NZW)F1 mice. Lupus 2015; 25:137-54. [PMID: 26385218 DOI: 10.1177/0961203315603139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 07/29/2015] [Indexed: 11/16/2022]
Abstract
Lupus is an autoimmune disease characterized by the development of antinuclear autoantibodies and immune complex-mediated tissue damage. T cells in lupus patients appear to undergo apoptosis at an increased rate, and this enhanced T cell apoptosis has been postulated to contribute to lupus pathogenesis by increasing autoantigen load. However, there is no direct evidence to support this hypothesis. In this study, we show that an Lck-cre transgene, which increases T cell apoptosis as a result of T cell-specific expression of cre recombinase, accelerates the development of autoantibodies and nephritis in lupus-prone (NZB × NZW)F1 mice. Although the enhanced T cell apoptosis in Lck-cre transgenic mice resulted in an overall decrease in the relative abundance of splenic CD4(+) and CD8(+) T cells, the proportion of activated CD4(+) T cells was increased and no significant change was observed in the relative abundance of suppressive T cells. We postulate that the Lck-cre transgene promoted lupus by enhancing T cell apoptosis, which, in conjunction with the impaired clearance of apoptotic cells in lupus-prone mice, increased the nuclear antigen load and accelerated the development of anti-nuclear autoantibodies. Furthermore, our results also underscore the importance of including cre-only controls in studies using the cre-lox system.
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Affiliation(s)
- R K Nelson
- Department of Genetics, Cell Biology & Anatomy, Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - K A Gould
- Department of Genetics, Cell Biology & Anatomy, Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, USA
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58
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Li J, Shou J, Guo Y, Tang Y, Wu Y, Jia Z, Zhai Y, Chen Z, Xu Q, Wu Q. Efficient inversions and duplications of mammalian regulatory DNA elements and gene clusters by CRISPR/Cas9. J Mol Cell Biol 2015; 7:284-98. [PMID: 25757625 PMCID: PMC4524425 DOI: 10.1093/jmcb/mjv016] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/02/2015] [Indexed: 12/26/2022] Open
Abstract
The human genome contains millions of DNA regulatory elements and a large number of gene clusters, most of which have not been tested experimentally. The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9) programed with a synthetic single-guide RNA (sgRNA) emerges as a method for genome editing in virtually any organisms. Here we report that targeted DNA fragment inversions and duplications could easily be achieved in human and mouse genomes by CRISPR with two sgRNAs. Specifically, we found that, in cultured human cells and mice, efficient precise inversions of DNA fragments ranging in size from a few tens of bp to hundreds of kb could be generated. In addition, DNA fragment duplications and deletions could also be generated by CRISPR through trans-allelic recombination between the Cas9-induced double-strand breaks (DSBs) on two homologous chromosomes (chromatids). Moreover, junctions of combinatorial inversions and duplications of the protocadherin (Pcdh) gene clusters induced by Cas9 with four sgRNAs could be detected. In mice, we obtained founders with alleles of precise inversions, duplications, and deletions of DNA fragments of variable sizes by CRISPR. Interestingly, we found that very efficient inversions were mediated by microhomology-mediated end joining (MMEJ) through short inverted repeats. We showed for the first time that DNA fragment inversions could be transmitted through germlines in mice. Finally, we applied this CRISPR method to a regulatory element of the Pcdhα cluster and found a new role in the regulation of members of the Pcdhγ cluster. This simple and efficient method should be useful in manipulating mammalian genomes to study millions of regulatory DNA elements as well as vast numbers of gene clusters.
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Affiliation(s)
- Jinhuan Li
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Jia Shou
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Ya Guo
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Yuanxiao Tang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Yonghu Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Zhilian Jia
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Yanan Zhai
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Zhifeng Chen
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Quan Xu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
| | - Qiang Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Center for Comparative Biomedicine, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Center, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China Collaborative Innovation Center of Systems Biomedicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China
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Saunders A, Sabatini BL. Cre Activated and Inactivated Recombinant Adeno-Associated Viral Vectors for Neuronal Anatomical Tracing or Activity Manipulation. ACTA ACUST UNITED AC 2015; 72:1.24.1-1.24.15. [PMID: 26131660 DOI: 10.1002/0471142301.ns0124s72] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recombinant adeno-associated viruses (rAAVs) transcriptionally activated by Cre recombinase (Cre-On) are powerful tools for determining the anatomy and function of genetically defined neuronal types in transgenic Cre driver mice. Here we describe how rAAVs transcriptionally inactivated by Cre (Cre-Off) can be used in conjunction with Cre-On rAAVs or genomic Cre-reporter alleles to study brain circuits. Intracranial injection of Cre-On/Cre-Off rAAVs into spatially intermingled Cre(+) and Cre(-) neurons allows these populations to be differentially labeled or manipulated within individual animals. This comparison helps define the unique properties of Cre(+) neurons, highlighting the specialized role they play in their constituent brain circuits. This protocol touches on the conceptual and experimental background of Cre-Off rAAV systems, including caveats and methods of validation.
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Affiliation(s)
- Arpiar Saunders
- Department of Neurobiology, Harvard Medical School, Howard Hughes Medical Institute, Boston, Massachusetts
| | - Bernardo L Sabatini
- Department of Neurobiology, Harvard Medical School, Howard Hughes Medical Institute, Boston, Massachusetts
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60
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Larsen RS, Smith IT, Miriyala J, Han JE, Corlew RJ, Smith SL, Philpot BD. Synapse-specific control of experience-dependent plasticity by presynaptic NMDA receptors. Neuron 2014; 83:879-93. [PMID: 25144876 DOI: 10.1016/j.neuron.2014.07.039] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2014] [Indexed: 12/15/2022]
Abstract
Sensory experience orchestrates the development of cortical circuitry by adaptively modifying neurotransmission and synaptic connectivity. However, the mechanisms underlying these experience-dependent modifications remain elusive. Here we demonstrate that visual experience suppresses a presynaptic NMDA receptor (preNMDAR)-mediated form of timing-dependent long-term depression (tLTD) at visual cortex layer (L) 4-2/3 synapses. This tLTD can be maintained during development, or reinstated in adulthood, by sensory deprivation. The changes in tLTD are mirrored by changes in glutamate release; visual deprivation enhances both tLTD and glutamate release. These effects require the GluN3A NMDAR subunit, the levels of which are increased by visual deprivation. Further, by coupling the pathway-specific optogenetic induction of tLTD with cell-type-specific NMDAR deletion, we find that visual experience modifies preNMDAR-mediated plasticity specifically at L4-L2/3 synapses.
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Affiliation(s)
- Rylan S Larsen
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ikuko T Smith
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jayalakshmi Miriyala
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ji Eun Han
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Rebekah J Corlew
- Neurobiology Curriculum, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Spencer L Smith
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Neurobiology Curriculum, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Benjamin D Philpot
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA; Neurobiology Curriculum, University of North Carolina, Chapel Hill, NC 27599, USA; UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC 27599, USA.
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Looso M. Opening the genetic toolbox of niche model organisms with high throughput techniques: novel proteins in regeneration as a case study. Bioessays 2014; 36:407-18. [PMID: 24741707 DOI: 10.1002/bies.201300093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Understanding in vivo regeneration of complex structures offers a fascinating perspective for translation into medical applications. Unfortunately, mammals in general lack large-scale regenerative capacity, whereas planarians, newts or Hydra can regenerate complete body parts. Such organisms are, however, poorly annotated because of the lack of sequence information. This leads to limited access for molecular biological investigations. In the last decade, high throughput technologies and new methods enabling the effective generation of transgenic animals have rapidly evolved. These developments have allowed the extensive use of niche model organisms as part of a trend towards the accessibility of a greater panel of model species for scientific research. The case study that follows provides an insight into the impact of high throughput techniques on the landscape of models of regeneration. The cases presented here give evidence of alternative stem cell maintenance pathways, the identification of new protein families and new stem cell markers.
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Kratochwil CF, Rijli FM. The Cre/Lox system to assess the development of the mouse brain. Methods Mol Biol 2014; 1082:295-313. [PMID: 24048942 DOI: 10.1007/978-1-62703-655-9_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Cre-mediated recombination has become a powerful tool to confine gene deletions (conditional knockouts) or overexpression of genes (conditional knockin/overexpression). By spatiotemporal restriction of genetic manipulations, major problems of classical knockouts such as embryonic lethality can be circumvented. Furthermore Cre-mediated recombination has broad applicability in the analysis of the cellular behavior of subpopulations and cell types as well as for genetic fate mapping. This chapter will give an overview about applications for the Cre/LoxP system and their execution.
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Precise and in situ genetic humanization of 6 Mb of mouse immunoglobulin genes. Proc Natl Acad Sci U S A 2014; 111:5147-52. [PMID: 24706858 DOI: 10.1073/pnas.1323896111] [Citation(s) in RCA: 272] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Genetic humanization, which involves replacing mouse genes with their human counterparts, can create powerful animal models for the study of human genes and diseases. One important example of genetic humanization involves mice humanized for their Ig genes, allowing for human antibody responses within a mouse background (HumAb mice) and also providing a valuable platform for the generation of fully human antibodies as therapeutics. However, existing HumAb mice do not have fully functional immune systems, perhaps because of the manner in which they were genetically humanized. Heretofore, most genetic humanizations have involved disruption of the endogenous mouse gene with simultaneous introduction of a human transgene at a new and random location (so-called KO-plus-transgenic humanization). More recent efforts have attempted to replace mouse genes with their human counterparts at the same genetic location (in situ humanization), but such efforts involved laborious procedures and were limited in size and precision. We describe a general and efficient method for very large, in situ, and precise genetic humanization using large compound bacterial artificial chromosome-based targeting vectors introduced into mouse ES cells. We applied this method to genetically humanize 3-Mb segments of both the mouse heavy and κ light chain Ig loci, by far the largest genetic humanizations ever described. This paper provides a detailed description of our genetic humanization approach, and the companion paper reports that the humoral immune systems of mice bearing these genetically humanized loci function as efficiently as those of WT mice.
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Bigda JJ, Koszałka P. Wacław Szybalski's contribution to immunotherapy: HGPRT mutation & HAT selection as first steps to gene therapy and hybrid techniques in mammalian cells. Gene 2013; 525:158-61. [DOI: 10.1016/j.gene.2013.03.099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Revised: 02/27/2013] [Accepted: 03/07/2013] [Indexed: 01/04/2023]
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65
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Gao J, Gu X, Mahuran DJ, Wang Z, Zhang H. Impaired glucose tolerance in a mouse model of sidt2 deficiency. PLoS One 2013; 8:e66139. [PMID: 23776622 PMCID: PMC3679015 DOI: 10.1371/journal.pone.0066139] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 05/02/2013] [Indexed: 11/18/2022] Open
Abstract
Sidt2 was identified as a novel integral lysosomal membrane protein recently. We generated global Sidt2 knockout mice by gene targeting. These mice have a comparatively higher random and fasting glucose concentration. Intraperitoneal and oral glucose tolerance tests in Sidt2 knockout mice indicated glucose intolerance and decreased serum insulin level. Notably, the Sidt2(-/-) mice had hypertrophic islets compared with control mice. By Western blot and immunofluorescence, Sidt2(-/-) mouse islets were shown to have increased insulin protein, which actually contained more insulin secretory granules than their controls, demonstrated by electromicroscopy. Consistent with the in vivo study, isolated islet culture from the Sidt2(-/-) mice produced less insulin when stimulated by a high concentration of glucose or a depolarizing concentration of KCl. Under electromicroscope less empty vesicles and more mature ones in Sidt2(-/-) mice islets were observed, supporting impaired insulin secretory granule release. In conclusion, Sidt2 may play a critical role in the regulation of mouse insulin secretory granule secretion.
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Affiliation(s)
- Jialin Gao
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuefan Gu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (XG); (HZ)
| | - Don J. Mahuran
- Department of Laboratory Medicine & Pathobiology, Research Institute, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Zhugang Wang
- Shanghai Research Centre for Model Organisms, Shanghai, China
| | - Huiwen Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (XG); (HZ)
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Abstract
Pancreatic cancer is critical for developed countries, where its rate of diagnosis has been increasing steadily annually. In the past decade, the advances of pancreatic cancer research have not contributed to the decline in mortality rates from pancreatic cancer-the overall 5-year survival rate remains about 5% low. This number only underscores an obvious urgency for us to better understand the biological features of pancreatic carcinogenesis, to develop early detection methods, and to improve novel therapeutic treatments. To achieve these goals, animal modeling that faithfully recapitulates the whole process of human pancreatic cancer is central to making the advancements. In this review, we summarize the currently available animal models for pancreatic cancer and the advances in pancreatic cancer animal modeling. We compare and contrast the advantages and disadvantages of three major categories of these models: (1) carcinogen-induced; (2) xenograft and allograft; and (3) genetically engineered mouse models. We focus more on the genetically engineered mouse models, a category which has been rapidly expanded recently for their capacities to mimic human pancreatic cancer and metastasis, and highlight the combinations of these models with various newly developed strategies and cell-lineage labeling systems.
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Affiliation(s)
- Wanglong Qiu
- Department of Otolaryngology and Head and Neck Surgery, Columbia University Medical Center, 1130 St. Nicholas Ave, ICRC 10-04, New York, NY 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
| | - Gloria H. Su
- Department of Otolaryngology and Head and Neck Surgery, Columbia University Medical Center, 1130 St. Nicholas Ave, ICRC 10-04, New York, NY 10032, USA
- Department of Pathology, Columbia University Medical Center, New York, NY 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
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67
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Sung LY, Chen CL, Lin SY, Hwang SM, Lu CH, Li KC, Lan AS, Hu YC. Enhanced and prolonged baculovirus-mediated expression by incorporating recombinase system and in cis elements: a comparative study. Nucleic Acids Res 2013; 41:e139. [PMID: 23716635 PMCID: PMC3737544 DOI: 10.1093/nar/gkt442] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Baculovirus (BV) is a promising gene vector but mediates transient expression. To prolong the expression, we developed a binary system whereby the transgene in the substrate BV was excised by the recombinase (ΦC31o, Cre or FLPo) expressed by a second BV and recombined into smaller minicircle. The recombination efficiency was lower by ΦC31o (≈40–75%), but approached ≈90–95% by Cre and FLPo in various cell lines and stem cells [e.g. human adipose-derived stem cells (hASCs)]. Compared with FLPo, Cre exerted higher expression level and lower negative effects; thus, we incorporated additional cis-acting element [oriP/Epstein–Barr virus nuclear antigen 1 (EBNA1), scaffold/matrix attached region or human origin of replication (ori)] into the Cre-based BV system. In proliferating cells, only oriP/EBNA1 prolonged the transgene expression and maintained the episomal minicircles for 30 days without inadvertent integration, whereas BV genome was degraded in 10 days. When delivering bmp2 or vegf genes, the efficient recombination/minicircle formation prolonged and enhanced the growth factor expression in hASCs. The prolonged bone morphogenetic protein 2 expression ameliorated the osteogenesis of hASCs, a stem cell with poor osteogenesis potential. Altogether, this BV vector exploiting Cre-mediated recombination and oriP/EBNA1 conferred remarkably high recombination efficiency, which prolonged and enhanced the transgene expression in dividing and non-dividing cells, thereby broadening the applications of BV.
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Affiliation(s)
- Li-Yu Sung
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
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Murata M, Shibata F, Hironaka A, Kashihara K, Fujimoto S, Yokota E, Nagaki K. Generation of an artificial ring chromosome in Arabidopsis by Cre/LoxP-mediated recombination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:363-371. [PMID: 23360080 DOI: 10.1111/tpj.12128] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/21/2013] [Accepted: 01/24/2013] [Indexed: 06/01/2023]
Abstract
A eukaryotic chromosome consists of a centromere, two telomeres and a number of replication origins, and 'artificial chromosomes' may be created in yeast and mammals when these three elements are artificially joined and introduced into cells. Plant artificial chromosomes (PACs) have been suggested as new vectors for the development of new crops and as tools for basic research on chromosomes. However, indisputable PAC formation has not yet been confirmed. Here, we present a method for generating PACs in the model plant Arabidopsis thaliana using the Cre/LoxP and Activator/Dissociation element systems. The successfully generated PAC, designated AtARC1 (A. thaliana artificial ring chromosome 1), originated from a centromeric edge of the long arm of chromosome 2, but its size (2.85 Mb) is much smaller than that of the original chromosome (26.3 Mb). Although AtARC1 contains only a short centromere domain consisting of 180 bp repeats approximately 250 kb in length, compared with the 3 Mb domain on the original chromosome 2, centromere-specific histone H3 (HTR12) was detected on the centromeric region. This result supported the observed stability of the PAC during mitosis in the absence of selection, and transmission of the PAC to the next generation through meiosis. Because AtARC1 contains a unique LoxP site driven by the CaMV 35S promoter, it is possible to introduce a selectable marker and desired transgenes into AtARC1 at the LoxP site using Cre recombinase. Therefore, AtARC1 meets the criteria for a PAC and is a promising vector.
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Affiliation(s)
- Minoru Murata
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan.
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69
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Abstract
Gene targeting in embryonic stem (ES) cells coupled with the site-specific Cre/loxP recombination system offers unique opportunities to identify and analyze the roles of cis-acting sequences in the regulation of imprinted gene expression. Although several different approaches have been described to engineer large chromosomal rearrangements in ES cells, these strategies can be labor-intensive and often require several subcloning of the original stem cells, therefore limiting the chances of obtaining germ line transmission of the mutation introduced. Here we describe an alternative approach which is based on in vivo recombination, therefore limiting the number of steps performed in ES cells and allowing to take advantage of the growing number of loxP insertional mutations already available in transgenic mice.
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Cox BC, Liu Z, Lagarde MMM, Zuo J. Conditional gene expression in the mouse inner ear using Cre-loxP. J Assoc Res Otolaryngol 2012; 13:295-322. [PMID: 22526732 PMCID: PMC3346893 DOI: 10.1007/s10162-012-0324-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/19/2012] [Indexed: 10/28/2022] Open
Abstract
In recent years, there has been significant progress in the use of Cre-loxP technology for conditional gene expression in the inner ear. Here, we introduce the basic concepts of this powerful technology, emphasizing the differences between Cre and CreER. We describe the creation and Cre expression pattern of each Cre and CreER mouse line that has been reported to have expression in auditory and vestibular organs. We compare the Cre expression patterns between Atoh1-CreER(TM) and Atoh1-CreER(T2) and report a new line, Fgfr3-iCreER(T2), which displays inducible Cre activity in cochlear supporting cells. We also explain how results can vary when transgenic vs. knock-in Cre/CreER alleles are used to alter gene expression. We discuss practical issues that arise when using the Cre-loxP system, such as the use of proper controls, Cre efficiency, reporter expression efficiency, and Cre leakiness. Finally, we introduce other methods for conditional gene expression, including Flp recombinase and the tetracycline-inducible system, which can be combined with Cre-loxP mouse models to investigate conditional expression of more than one gene.
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Affiliation(s)
- Brandon C. Cox
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
| | - Zhiyong Liu
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
| | - Marcia M. Mellado Lagarde
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
| | - Jian Zuo
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105 USA
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Chen MR, Kao VYY, Liu SW, Wu TC, Yu HC, Hsu CH, Chen CT, Lin KM. NONINVASIVE OPTICAL IMAGING FOR TRACKING GENE DELIVERY AND RECOMBINATION IN TUMOR. BIOMEDICAL ENGINEERING-APPLICATIONS BASIS COMMUNICATIONS 2012. [DOI: 10.4015/s1016237209001441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here, we report the generation of optical imaging reporter breast tumor cells that allow the longitudinal, in vivo, noninvasive imaging of gene recombination in tumor. Tumor-gene targeting is a promising approach of treating cancers, and a suitable gene delivery method is the criteria for success. By using the cre lox genetic engineering tool, we targeted stable green fluorescent protein expression in metastatic-prone human breast cancer MDA-MB231 cells that switch to express firefly luciferase upon the exogenous delivery and expression of cre DNA recombinase. We tested this model in vivo by intratumor injection of cre adenovirus and demonstrated the usefulness of this model to achieve longitudinal bioluminescence imaging of DNA recombination in tumor. This optical imaging vector and tumor model will facilitate the research for biomaterial solutions for carriers in gene therapy, and in studies on tumor targeting, tracking for tumor metastasis and migration of tumor stem cells, and for determining the anticancer drug efficacy.
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Affiliation(s)
- Mei-Ru Chen
- Division of Medical Engineering Research, National Health Research Institutes, Zhunan Town, Miaoli, Taiwan
| | - Vivia Yu-Ying Kao
- Department of Biotechnology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Shan-Wen Liu
- Division of Medical Engineering Research, National Health Research Institutes, Zhunan Town, Miaoli, Taiwan
- Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Tzu-Chin Wu
- Division of Medical Engineering Research, National Health Research Institutes, Zhunan Town, Miaoli, Taiwan
| | - Hsiao-Chi Yu
- Division of Medical Engineering Research, National Health Research Institutes, Zhunan Town, Miaoli, Taiwan
| | - Chin-Han Hsu
- Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Chin-Tu Chen
- Department of Radiology and Committee on Medical Physics, University of Chicago, IL, USA
| | - Kurt M. Lin
- Division of Medical Engineering Research, National Health Research Institutes, Zhunan Town, Miaoli, Taiwan
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72
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Price BA, Sandoval IM, Chan F, Simons DL, Wu SM, Wensel TG, Wilson JH. Mislocalization and degradation of human P23H-rhodopsin-GFP in a knockin mouse model of retinitis pigmentosa. Invest Ophthalmol Vis Sci 2011; 52:9728-36. [PMID: 22110080 PMCID: PMC3341127 DOI: 10.1167/iovs.11-8654] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/08/2011] [Accepted: 11/08/2011] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To engineer a knockin mouse model that can be used to monitor the effects of treatments on degradation and mislocalization of proline-to-histidine change at codon 23 (P23H) rhodopsin, a common cause of autosomal dominant retinitis pigmentosa (ADRP). The goal was to introduce a gene that expressed rhodopsin at low levels to avoid rapid retinal degeneration, and with a readily visible tag to make it easy to distinguish from wild type rhodopsin. METHODS One copy of the endogenous mouse rhodopsin gene was replaced with a mutant human rhodopsin gene that encodes P23H-rhodopsin fused to enhanced green fluorescent protein (GFP) at its C terminus. The gene includes a LoxP site in the sequence corresponding to the 5'-untranslated region, which greatly reduces translation efficiency. Characterized are the resulting heterozygous and homozygous P23H-hRho-GFP mouse lines for mRNA and protein expression, P23H-rhodopsin localization in rod cells, effects on visual function, and retinal degeneration. RESULTS The retinas of heterozygous P23H-hRho-GFP mice are morphologically and functionally very similar to those of wild type mice, and they display little cell death over time. P23H-hRho-GFP mice transcribe the knockin gene as efficiently as the endogenous mouse allele, but they contain much less of the protein product than do knockin mice expressing nonmutant hRho-GFP, indicating that substantial degradation of P23H-rRho-GFP occurs in mouse rod cells. The remaining P23H-hRho-GFP mislocalizes to the inner segment and outer nuclear layer, with only approximately 20% in rod outer segments. CONCLUSIONS P23H-hRho-GFP mice provide a valuable tool for evaluating the efficacy of potential therapies for ADRP that influence the levels or localization of P23H-rhodopsin.
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Affiliation(s)
- Brandee A. Price
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, and
- the Departments of Molecular and Human Genetics and
| | - Ivette M. Sandoval
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, and
| | - Fung Chan
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, and
| | | | - Samuel M. Wu
- Ophthalmology, Baylor College of Medicine, Houston, Texas
| | - Theodore G. Wensel
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, and
| | - John H. Wilson
- From the Verna and Marrs McLean Department of Biochemistry and Molecular Biology, and
- the Departments of Molecular and Human Genetics and
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73
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Husse J, Zhou X, Shostak A, Oster H, Eichele G. Synaptotagmin10-Cre, a driver to disrupt clock genes in the SCN. J Biol Rhythms 2011; 26:379-89. [PMID: 21921292 DOI: 10.1177/0748730411415363] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Surgical lesion of the suprachiasmatic nuclei (SCN) profoundly affects the circadian timing system. A complication of SCN ablations is the concomitant scission of SCN afferents and efferents. Genetic disruption of the molecular clockwork in the SCN provides a complementary, less invasive experimental approach. The authors report the generation and functional analysis of a new Cre recombinase driver mouse that evokes homologous recombination with high efficiency in the SCN. They inserted the Cre recombinase cDNA into the Synaptotagmin10 (Syt10) locus, a gene strongly expressed in the SCN. Heterozygous Synaptotagmin10-Cre (Syt10(Cre)) mice have no obvious circadian locomotor phenotype, and homozygous animals show slightly reduced light-induced phase delays. Crosses of Syt10(Cre) mice with β-galactosidase reporter animals revealed strong Cre activity in the vast majority of SCN cells. Cre activity is not detected in nonneuronal tissues with the exception of the testis. The authors demonstrate that conditionally deleting the clock gene Bmal1 using the Syt10(Cre) driver renders animals arrhythmic.
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Affiliation(s)
- Jana Husse
- Genes and Behavior Department, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany
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74
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Hérault Y, Duchon A, Maréchal D, Raveau M, Pereira PL, Dalloneau E, Brault V. Controlled somatic and germline copy number variation in the mouse model. Curr Genomics 2011; 11:470-80. [PMID: 21358991 PMCID: PMC3018727 DOI: 10.2174/138920210793176038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 05/24/2010] [Accepted: 05/27/2010] [Indexed: 12/20/2022] Open
Abstract
Changes in the number of chromosomes, but also variations in the copy number of chromosomal regions have been described in various pathological conditions, such as cancer and aneuploidy, but also in normal physiological condition. Our classical view of DNA replication and mitotic preservation of the chromosomal integrity is now challenged as new technologies allow us to observe such mosaic somatic changes in copy number affecting regions of chromosomes with various sizes. In order to go further in the understanding of copy number influence in normal condition we could take advantage of the novel strategy called Targeted Asymmetric Sister Chromatin Event of Recombination (TASCER) to induce recombination during the G2 phase so that we can generate deletions and duplications of regions of interest prior to mitosis. Using this approach in the mouse we could address the effects of copy number variation and segmental aneuploidy in daughter cells and allow us to explore somatic mosaics for large region of interest in the mouse.
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Affiliation(s)
- Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Illkirch, France
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Chan F, Hauswirth WW, Wensel TG, Wilson JH. Efficient mutagenesis of the rhodopsin gene in rod photoreceptor neurons in mice. Nucleic Acids Res 2011; 39:5955-66. [PMID: 21478169 PMCID: PMC3152346 DOI: 10.1093/nar/gkr196] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dominant mutations in the rhodopsin gene, which is expressed in rod photoreceptor cells, are a major cause of the hereditary-blinding disease, autosomal dominant retinitis pigmentosa. Therapeutic strategies designed to edit such mutations will likely depend on the introduction of double-strand breaks and their subsequent repair by homologous recombination or non-homologous end joining. At present, the break repair capabilities of mature neurons, in general, and rod cells, in particular, are undefined. To detect break repair, we generated mice that carry a modified human rhodopsin-GFP fusion gene at the normal mouse rhodopsin locus. The rhodopsin-GFP gene carries tandem copies of exon 2, with an ISceI recognition site situated between them. An ISceI-induced break can be repaired either by non-homologous end joining or by recombination between the duplicated segments, generating a functional rhodopsin-GFP gene. We introduced breaks using recombinant adeno-associated virus to transduce the gene encoding ISceI nuclease. We found that virtually 100% of transduced rod cells were mutated at the ISceI site, with ∼85% of the genomes altered by end joining and ∼15% by the single-strand annealing pathway of homologous recombination. These studies establish that the genomes of terminally differentiated rod cells can be efficiently edited in living organisms.
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Affiliation(s)
- Fung Chan
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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76
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Genome organization influences partner selection for chromosomal rearrangements. Trends Genet 2010; 27:63-71. [PMID: 21144612 DOI: 10.1016/j.tig.2010.11.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 11/02/2010] [Accepted: 11/03/2010] [Indexed: 11/22/2022]
Abstract
Chromosomal rearrangements occur as a consequence of the erroneous repair of DNA double-stranded breaks, and often underlie disease. The recurrent detection of specific tumorigenic rearrangements suggests that there is a mechanism behind chromosomal partner selection involving the shape of the genome. With the advent of novel high-throughput approaches, detailed genome integrity and folding maps are becoming available. Integrating these data with knowledge of experimentally induced DNA recombination strongly suggests that partner choice in chromosomal rearrangement primarily follows the three-dimensional conformation of the genome. Local rearrangements are favored over distal and interchromosomal rearrangements. This is seen for neutral rearrangements, but not necessarily for rearrangements that drive oncogenesis. The recurrent detection of tumorigenic rearrangements probably reflects their exceptional capacity to confer growth advantage to the rare cells that contain them. The abundant presence of neutral rearrangements suggests that somatic genome variation is also common in healthy tissue.
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Cazzin C, Zanderigo F, Costantini VJA, Zambello E, Ring CJA, Morrison AD, Caberlotto L, Kew JNC. Adenoviral-mediated Cre expression effectively suppresses GlyT1 binding in the thalamic area of GlyT1 conditional knock-out mice. J Neurosci Methods 2010; 193:254-63. [PMID: 20832426 DOI: 10.1016/j.jneumeth.2010.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 08/31/2010] [Accepted: 09/01/2010] [Indexed: 12/20/2022]
Abstract
To properly understand the function of genes of neurological interest, in vivo manipulation in the adult is essential, particularly when the target gene is involved in brain development. Moreover, since the physiological effects of target protein may be region-specific, targeting a distinct brain region could be required to dissect these effects in specific brain locations. Infection of somatic tissues of transgenic mice bearing loxP-flanked gene sequences with a viral vector expressing Cre recombinase provides a means of allowing flexible spatio-temporal control of target gene expression. Viral vector-mediated Cre expression could be used to mediate localized gene modulation in a specific brain region. In the present study this technology was applied to the glycine transporter type-1 (GlyT1) protein which is responsible for the uptake of synaptic glycine in the forebrain and has been implicated as a therapeutic target for the treatment of schizophrenia. Since GlyT1 is widely expressed in glial cells, we employed an adenoviral-based vector (Ad5) to deliver Cre protein, due to the preferentially transduction of glial cells by adenoviral vectors in rodent brain. We show significant reduced GlyT1 binding specifically in the thalamic area of conditional GlyT1 (GlyT1c) transgenic mice injected with Ad5-Cre virus, as measured by GlyT1 autoradiography. In conclusion, we demonstrated the validity of viral vector-mediated delivery of Cre to loxP targeted transgenic mice as a novel strategy to investigate target gene function in selected subregions of the adult brain, which provides a valuable technique to investigate gene function both in normal physiology and in disease models.
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Affiliation(s)
- Chiara Cazzin
- Biology Department A&S DPU, Neurosciences CEDD, GlaxoSmithKline, Medicines Research Center, Verona, Italy.
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78
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Abstract
Cre/loxP recombination enables cellular specificity and, in the case of inducible systems, temporal control of genomic deletions. Here we used a SM22α tamoxifen-inducible Cre line to inactivate β1 integrin in adult smooth muscle. Interestingly, analysis of two distinct β1 loxP transgenic mice revealed vastly different outcomes after β1 integrin deletion. Lethality occurred 4 weeks postinduction in one Cre/loxP line, while no apparent phenotype was seen in the other line. Genetic analysis revealed appropriate DNA excision in both cases; however, differences were found in the degree of protein loss with absolutely no change in protein levels in the model that lacked a phenotype. Seeking to understand protein persistence despite appropriate recombination, we first validated the flox allele using a constitutive Cre line and demonstrated its ability to mediate effective protein inactivation. We then examined the possibility of heterozygous cell selection, protein turnover, and deletion efficiency with no success for explaining the phenotype. Finally, we documented the presence of the Cre-recombination episomal product, which persisted in tissue samples with no protein loss. The product was only noted in cells with low proliferative capacity. These findings highlight the potential for protein expression from the products of Cre-recombinase excised genes, particularly when deletion occurs in low turnover populations.
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79
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Jiang YH, Pan Y, Zhu L, Landa L, Yoo J, Spencer C, Lorenzo I, Brilliant M, Noebels J, Beaudet AL. Altered ultrasonic vocalization and impaired learning and memory in Angelman syndrome mouse model with a large maternal deletion from Ube3a to Gabrb3. PLoS One 2010; 5:e12278. [PMID: 20808828 PMCID: PMC2924885 DOI: 10.1371/journal.pone.0012278] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 07/19/2010] [Indexed: 11/21/2022] Open
Abstract
Angelman syndrome (AS) is a neurobehavioral disorder associated with mental retardation, absence of language development, characteristic electroencephalography (EEG) abnormalities and epilepsy, happy disposition, movement or balance disorders, and autistic behaviors. The molecular defects underlying AS are heterogeneous, including large maternal deletions of chromosome 15q11–q13 (70%), paternal uniparental disomy (UPD) of chromosome 15 (5%), imprinting mutations (rare), and mutations in the E6-AP ubiquitin ligase gene UBE3A (15%). Although patients with UBE3A mutations have a wide spectrum of neurological phenotypes, their features are usually milder than AS patients with deletions of 15q11–q13. Using a chromosomal engineering strategy, we generated mutant mice with a 1.6-Mb chromosomal deletion from Ube3a to Gabrb3, which inactivated the Ube3a and Gabrb3 genes and deleted the Atp10a gene. Homozygous deletion mutant mice died in the perinatal period due to a cleft palate resulting from the null mutation in Gabrb3 gene. Mice with a maternal deletion (m−/p+) were viable and did not have any obvious developmental defects. Expression analysis of the maternal and paternal deletion mice confirmed that the Ube3a gene is maternally expressed in brain, and showed that the Atp10a and Gabrb3 genes are biallelically expressed in all brain sub-regions studied. Maternal (m−/p+), but not paternal (m+/p−), deletion mice had increased spontaneous seizure activity and abnormal EEG. Extensive behavioral analyses revealed significant impairment in motor function, learning and memory tasks, and anxiety-related measures assayed in the light-dark box in maternal deletion but not paternal deletion mice. Ultrasonic vocalization (USV) recording in newborns revealed that maternal deletion pups emitted significantly more USVs than wild-type littermates. The increased USV in maternal deletion mice suggests abnormal signaling behavior between mothers and pups that may reflect abnormal communication behaviors in human AS patients. Thus, mutant mice with a maternal deletion from Ube3a to Gabrb3 provide an AS mouse model that is molecularly more similar to the contiguous gene deletion form of AS in humans than mice with Ube3a mutation alone. These mice will be valuable for future comparative studies to mice with maternal deficiency of Ube3a alone.
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Affiliation(s)
- Yong-Hui Jiang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America.
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80
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Oh-McGinnis R, Jones MJ, Lefebvre L. Applications of the site-specific recombinase Cre to the study of genomic imprinting. Brief Funct Genomics 2010; 9:281-93. [PMID: 20601421 DOI: 10.1093/bfgp/elq017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The development of gene targeting approaches has had a tremendous impact on the functional analysis of the mouse genome. A specific application of this technique has been the adaptation of the bacteriophage P1 Cre/loxP site-specific recombinase system which allows for the precise recombination between two loxP sites, resulting in deletion or inversion of the intervening sequences. Because of the efficiency of this system, it can be applied to conditional deletions of relatively short coding sequences or regulatory elements but also to more extensive chromosomal rearrangement strategies. Both mechanistic and functional studies of genomic imprinting have benefited from the development of the Cre/loxP technology. Since imprinted genes within large chromosomal regions are regulated by the action of cis-acting sequences known as imprinting centers, chromosomal engineering approaches are particularly well suited to the elucidation of long-range mechanisms controlling the imprinting of autosomal genes. Here we review the applications of the Cre/loxP technology to the study of genomic imprinting, highlight important insights gained from these studies and discuss future directions in the field.
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Affiliation(s)
- Rosemary Oh-McGinnis
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
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81
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Uemura M, Niwa Y, Kakazu N, Adachi N, Kinoshita K. Chromosomal manipulation by site-specific recombinases and fluorescent protein-based vectors. PLoS One 2010; 5:e9846. [PMID: 20352097 PMCID: PMC2844420 DOI: 10.1371/journal.pone.0009846] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 03/03/2010] [Indexed: 11/24/2022] Open
Abstract
Feasibility of chromosomal manipulation in mammalian cells was first reported 15 years ago. Although this technique is useful for precise understanding of gene regulation in the chromosomal context, a limited number of laboratories have used it in actual practice because of associated technical difficulties. To overcome the practical hurdles, we developed a Cre-mediated chromosomal recombination system using fluorescent proteins and various site-specific recombinases. These techniques enabled quick construction of targeting vectors, easy identification of chromosome-rearranged cells, and rearrangement leaving minimum artificial elements at junctions. Applying this system to a human cell line, we successfully recapitulated two types of pathogenic chromosomal translocations in human diseases: MYC/IgH and BCR/ABL1. By inducing recombination between two loxP sites targeted into the same chromosome, we could mark cells harboring deletion or duplication of the inter-loxP segments with different colors of fluorescence. In addition, we demonstrated that the intrachromosomal recombination frequency is inversely proportional to the distance between two recombination sites, implicating a future application of this frequency as a proximity sensor. Our method of chromosomal manipulation can be employed for particular cell types in which gene targeting is possible (e.g. embryonic stem cells). Experimental use of this system would open up new horizons in genome biology, including the establishment of cellular and animal models of diseases caused by translocations and copy-number variations.
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Affiliation(s)
- Munehiro Uemura
- Evolutionary Medicine, Shiga Medical Center Research Institute, Moriyama, Japan
| | - Youko Niwa
- Evolutionary Medicine, Shiga Medical Center Research Institute, Moriyama, Japan
| | - Naoki Kakazu
- Department of Environmental and Preventive Medicine, Shimane University School of Medicine, Izumo, Japan
| | - Noritaka Adachi
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Japan
| | - Kazuo Kinoshita
- Evolutionary Medicine, Shiga Medical Center Research Institute, Moriyama, Japan
- * E-mail:
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82
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Abstract
The chicken spinal cord is an excellent model for the study of early neural development in vertebrates. However, the lack of robust, stable and versatile transgenic methods has limited the usefulness of chick embryos for the study of later neurodevelopmental events. Here we describe a new transgenic approach utilizing the PiggyBac (PB) transposon to facilitate analysis of late-stage neural development such as axon targeting and synaptic connection in the chicken embryo. Using PB transgenic approaches we achieved temporal and spatial regulation of transgene expression and performed stable RNA interference (RNAi). With these new capabilities, we mapped axon projection patterns of V2b subset of spinal interneurons and visualized maturation of the neuromuscular junction (NMJ). Furthermore, PB-mediated RNAi in the chick recapitulated the phenotype of loss of agrin function in the mouse NMJ. The simplicity and versatility of PB-mediated transgenic strategies hold great promise for large-scale genetic analysis of neuronal connectivity in the chick.
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Affiliation(s)
| | | | - Xiaozhong Wang
- *To whom correspondence should be addressed. Tel: +1 847 467 4897; Fax: +1 847 467 1380;
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83
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Kameyama Y, Kawabe Y, Ito A, Kamihira M. An accumulative site-specific gene integration system using cre recombinase-mediated cassette exchange. Biotechnol Bioeng 2010; 105:1106-14. [DOI: 10.1002/bit.22619] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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84
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Polyploidy, Aneuploidy and the Evolution of Cancer. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 676:1-13. [DOI: 10.1007/978-1-4419-6199-0_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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85
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Voehringer D, Wu D, Liang HE, Locksley RM. Efficient generation of long-distance conditional alleles using recombineering and a dual selection strategy in replicate plates. BMC Biotechnol 2009; 9:69. [PMID: 19638212 PMCID: PMC2724507 DOI: 10.1186/1472-6750-9-69] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 07/28/2009] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Conditional knockout mice are a useful tool to study the function of gene products in a tissue-specific or inducible manner. Classical approaches to generate targeting vectors for conditional alleles are often limited by the availability of suitable restriction sites. Furthermore, plasmid-based targeting vectors can only cover a few kB of DNA which precludes the generation of targeting vectors where the two loxP sites are placed far apart. These limitations have been overcome in the recent past by using homologous recombination of bacterial artificial chromosomes (BACs) in Escherichia coli to produce large targeting vector containing two different loxP-flanked selection cassettes so that a single targeting event is sufficient to introduce loxP-sites a great distances into the mouse genome. However, the final targeted allele should be free of selection cassettes and screening for correct removal of selection cassettes can be a laborious task. Therefore, we developed a new strategy to rapidly identify ES cells containing the desired allele. RESULTS Using BAC recombineering we generated a single targeting vector which contained two different selection cassettes that were flanked by loxP-loxP sites or by FRT-FRT/loxP sites so that they could be deleted sequentially by Cre- and FLPe-recombinases, respectively. Transfected ES cells were first selected in the presence of both antibiotics in vitro before correctly targeted clones were identified by Southern blot. After transfection of a Cre recombinase expression plasmid ES cell clones were selected on replicate plates to identify those clones which maintained the FRT-FRT/loxP flanked cassette and lost the loxP-loxP flanked cassette. Using this strategy facilitated the identification of ES cell clones containing the desired allele before blastocyst injection. CONCLUSION The strategy of ES cell cultures in replicate plates proved to be very efficient in identifying ES cells that had undergone the correct recombination event. This approach facilitates the generation of conditional knock-out mice when large parts of the genome are intended to be flanked by loxP sites.
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Affiliation(s)
- David Voehringer
- Howard Hughes Medical Institute, Department of Medicine, University of California San Francisco, San Francisco, CA 94143-0795, USA.
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86
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Hu L, Zhu YT, Qi C, Zhu YJ. Identification of Smyd4 as a potential tumor suppressor gene involved in breast cancer development. Cancer Res 2009; 69:4067-72. [PMID: 19383909 DOI: 10.1158/0008-5472.can-08-4097] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To identify genes involved in breast tumorigenesis, we applied the retroviral LoxP-Cre system to a nontumorigenic mouse mammary epithelial cell line NOG8 to create random chromosome deletion/translocation. We found that the disruption of one allele of Smyd4 (SET and MYND domain containing 4) gene through chromosome translocation led to tumorigenesis. The expression of Smyd4 was markedly decreased in tumor cells. Re-expression of Smyd4 resulted in growth suppression of tumor cells and inhibition of tumor formation in nude mice. Furthermore, the RNA interference-mediated suppression of Smyd4 expression in human MCF10A mammary epithelial cells caused their growth in soft agar. Microarray studies revealed that platelet-derived growth factor receptor alpha polypeptide (Pdgfr-alpha) was highly expressed in tumor cells compared with NOG8 cells. Re-expression of Smyd4 significantly reduced the expression of Pdgfr-alpha in tumor cells. In human breast cancers, reverse transcription-PCR results revealed that Smyd4 expression was totally silenced in 2 of 10 specimens. These findings indicate that Smyd4, as a potential tumor suppressor, plays a critical role in breast carcinogenesis at least partly through inhibiting the expression of Pdgfr-alpha, and could be a novel target for improving treatment of breast cancer.
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Affiliation(s)
- Liping Hu
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-3008, USA
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87
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Wang SZ, Liu BH, Tao HW, Xia K, Zhang LI. A genetic strategy for stochastic gene activation with regulated sparseness (STARS). PLoS One 2009; 4:e4200. [PMID: 19145242 PMCID: PMC2615212 DOI: 10.1371/journal.pone.0004200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2008] [Accepted: 12/08/2008] [Indexed: 01/01/2023] Open
Abstract
It remains a challenge to establish a straightforward genetic approach for controlling the probability of gene activation or knockout at a desired level. Here, we developed a method termed STARS: stochastic gene activation with genetically regulated sparseness. The stochastic expression was achieved by two cross-linked, mutually-exclusive Cre-mediated recombinations. The stochastic level was further controlled by regulating Cre/lox reaction kinetics through varying the intrachromosomal distance between the lox sites mediating one of the recombinations. In mammalian cell lines stably transfected with a single copy of different STARS transgenes, the activation/knockout of reporter genes was specifically controlled to occur in from 5% to 50% of the cell population. STARS can potentially provide a convenient way for genetic labeling as well as gene expression/knockout in a population of cells with a desired sparseness level.
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Affiliation(s)
- Sheng-zhi Wang
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Bao-hua Liu
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Huizhong W. Tao
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Kun Xia
- The State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, People's Republic of China
| | - Li I. Zhang
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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88
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Abstract
Chromosomal rearrangements, such as deletions, duplications, inversions and translocations, occur frequently in humans and can be disease-associated or phenotypically neutral. To understand the genetic consequences of such genomic changes, these mutations need to be modelled in experimentally tractable systems. The mouse is an excellent organism for this analysis because of its biological and genetic similarity to humans, the ease with which its genome can be manipulated and the similarity of observed affects. Through chromosome engineering, defined rearrangements can be introduced into the mouse genome. The resulting mouse models are leading to a better understanding of the molecular and cellular basis of dosage alterations in human disease phenotypes, in turn opening new diagnostic and therapeutic opportunities.
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Affiliation(s)
- Louise van der Weyden
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, UK
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89
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A protocol for constructing gene targeting vectors: generating knockout mice for the cadherin family and beyond. Nat Protoc 2008; 3:1056-76. [PMID: 18546598 DOI: 10.1038/nprot.2008.70] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We describe here a streamlined procedure for targeting vector construction, which often is a limiting factor for gene targeting (knockout) technology. This procedure combines various highly efficient recombination-based cloning methods in bacteria, consisting of three steps. First step is the use of Red-pathway-mediated recombination (recombineering) to capture a genomic fragment into a Gateway-compatible vector. Second, the vector is modified by recombineering to include a positive selection gene neo, from a variety of modular reagents. Finally, through a simple in vitro Gateway recombination, the modified genomic fragment is switched into a vector that contains negative selection cassettes, as well as unique sites for linearization. To demonstrate the usefulness of this protocol, we report targeted disruptions of members of the cadherin gene family, focusing on those that have not been previously studied at the molecular genetic level. This protocol needs 2 weeks to construct a targeting vector, and several vectors can be easily handled simultaneously using common laboratory setup.
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90
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Inducing segmental aneuploid mosaicism in the mouse through targeted asymmetric sister chromatid event of recombination. Genetics 2008; 180:51-9. [PMID: 18757940 DOI: 10.1534/genetics.108.092312] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Loss or gain of whole chromosomes, or parts of chromosomes, is found in various pathological conditions, such as cancer and aneuploidy, and results from the missegregation of chromosomes during cellular division or abnormal mitotic recombination. We introduce a novel strategy for determining the consequences of segmental aneuploid mosaicism, called targeted asymmetric sister chromatin event of recombination (TASCER). We took advantage of the Cre/loxP system, used extensively in embryonic stem cells for generating deletions and duplications of regions of interest, to induce recombination during the G2 phase. Using two loxP sites in a Cis configuration, we generated in vivo cells harboring microdeletions and microduplications for regions of interest covering up to 2.2 Mb. Using this approach in the mouse provides insight into the consequences of segmental aneuploidy for homologous regions of the human chromosome 21 on cell survival. Furthermore, TASCER shows that Cre-induced recombination is more efficient after DNA replication in vivo and provides an opportunity to evaluate, through genetic mosaics, the outcome of copy number variation and segmental aneuploidy in the mouse.
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91
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Adams DJ, van der Weyden L. Contemporary approaches for modifying the mouse genome. Physiol Genomics 2008; 34:225-38. [PMID: 18559964 PMCID: PMC2519963 DOI: 10.1152/physiolgenomics.90242.2008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 06/11/2008] [Indexed: 12/05/2022] Open
Abstract
The mouse is a premiere experimental organism that has contributed significantly to our understanding of vertebrate biology. Manipulation of the mouse genome via embryonic stem (ES) cell technology makes it possible to engineer an almost limitless repertoire of mutations to model human disease and assess gene function. In this review we outline recent advances in mouse experimental genetics and provide a "how-to" guide for those people wishing to access this technology. We also discuss new technologies, such as transposon-mediated mutagenesis, and resources of targeting vectors and ES cells, which are likely to dramatically accelerate the pace with which we can assess gene function in vivo, and the progress of forward and reverse genetic screens in mice.
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Affiliation(s)
- David J Adams
- Experimental Cancer Genetics, The Wellcome Trust Sanger Institute, Hinxton, United Kingdom
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92
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Normal germ line establishment in mice carrying a deletion of the Ifitm/Fragilis gene family cluster. Mol Cell Biol 2008; 28:4688-96. [PMID: 18505827 DOI: 10.1128/mcb.00272-08] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The family of interferon-inducible transmembrane proteins (Ifitm) consists of five highly sequence-related cell surface proteins, which are implicated in diverse cellular processes. Ifitm genes are conserved, widely expressed, and characteristically found in genomic clusters, such as the 67-kb Ifitm family locus on mouse chromosome 7. Recently, Ifitm1 and Ifitm3 have been suggested to mediate migration of early primordial germ cells (PGCs), a process that is little understood. To investigate Ifitm function during germ cell development, we used targeted chromosome engineering to generate mutants which either lack the entire Ifitm locus or carry a disrupted Ifitm3 gene only. Here we show that the mutations have no detectable effects on development of the germ line or on the generation of live young. Hence, contrary to previous reports, Ifitm genes are not essential for PGC migration. The Ifitm family is a striking example of a conserved gene cluster which appears to be functionally redundant during development.
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93
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Livet J, Weissman TA, Kang H, Draft RW, Lu J, Bennis RA, Sanes JR, Lichtman JW. Transgenic strategies for combinatorial expression of fluorescent proteins in the nervous system. Nature 2007; 450:56-62. [PMID: 17972876 DOI: 10.1038/nature06293] [Citation(s) in RCA: 1277] [Impact Index Per Article: 75.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 09/25/2007] [Indexed: 01/19/2023]
Abstract
Detailed analysis of neuronal network architecture requires the development of new methods. Here we present strategies to visualize synaptic circuits by genetically labelling neurons with multiple, distinct colours. In Brainbow transgenes, Cre/lox recombination is used to create a stochastic choice of expression between three or more fluorescent proteins (XFPs). Integration of tandem Brainbow copies in transgenic mice yielded combinatorial XFP expression, and thus many colours, thereby providing a way to distinguish adjacent neurons and visualize other cellular interactions. As a demonstration, we reconstructed hundreds of neighbouring axons and multiple synaptic contacts in one small volume of a cerebellar lobe exhibiting approximately 90 colours. The expression in some lines also allowed us to map glial territories and follow glial cells and neurons over time in vivo. The ability of the Brainbow system to label uniquely many individual cells within a population may facilitate the analysis of neuronal circuitry on a large scale.
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Affiliation(s)
- Jean Livet
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, USA
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94
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Scahill MD, Pastar I, Cross GAM. CRE recombinase-based positive-negative selection systems for genetic manipulation in Trypanosoma brucei. Mol Biochem Parasitol 2007; 157:73-82. [PMID: 18006158 DOI: 10.1016/j.molbiopara.2007.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Revised: 09/28/2007] [Accepted: 10/03/2007] [Indexed: 11/24/2022]
Abstract
The limited repertoire of drug-resistance markers imposes a serious obstacle to genetic manipulation of Trypanosoma brucei. Here we describe experiments with a fusion protein that allows positive selection for genome integration followed by CRE recombinase-mediated excision of the marker cassette that can be selected by ganciclovir, although the excision event is so efficient that selection is not strictly necessary. We describe two variants of the tetracycline-inducible pLEW100-based CRE-expression vector that reduced its toxicity when stably integrated into the genome, and we demonstrate that transient transfection of circular pLEW100-CRE is highly efficient at catalyzing marker excision. We used this approach to delete the last two enzymes of the pyrimidine synthesis pathway, creating a cell line that is resistant to fluoroorotic acid, which would allow the same enzymes (PYR6-5) to be used as an alternative negative selectable marker.
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Affiliation(s)
- Michael D Scahill
- Laboratory of Molecular Parasitology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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95
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Qadota H, Inoue M, Hikita T, Köppen M, Hardin JD, Amano M, Moerman DG, Kaibuchi K. Establishment of a tissue-specific RNAi system in C. elegans. Gene 2007; 400:166-73. [PMID: 17681718 PMCID: PMC3086655 DOI: 10.1016/j.gene.2007.06.020] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 06/12/2007] [Accepted: 06/14/2007] [Indexed: 11/24/2022]
Abstract
In C. elegans, mosaic analysis is a powerful genetic tool for determining in which tissue or specific cells a gene of interest is required. For traditional mosaic analysis, a loss-of-function mutant and a genomic fragment that can rescue the mutant phenotype are required. Here we establish an easy and rapid mosaic system using RNAi (RNA mediated interference), using a rde-1 mutant that is resistant to RNAi. Tissue-specific expression of the wild type rde-1 cDNA in rde-1 mutants limits RNAi sensitivity to a specific tissue. We established hypodermal-and muscle-specific RNAi systems by expressing rde-1 cDNA under the control of the lin-26 and hlh-1 promoters, respectively. We confirmed tissue-specific RNAi using two assays: (1) tissue-specific knockdown of GFP expression, and (2) phenocopy of mutations in essential genes that were previously known to function in a tissue-specific manner. We also applied this system to an essential gene, ajm-1, expressed in hypodermis and gut, and show that lethality in ajm-1 mutants is due to loss of expression in hypodermal cells. Although we demonstrate tissue-specific RNAi in hypodermis and muscle, this method could be easily applied to other tissues.
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Affiliation(s)
- Hiroshi Qadota
- Division of Signal Transduction, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara 630-0101, Japan.
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96
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Zhu YT, Qi C, Hu L, Zhu YJ. Efficient generation of random chromosome deletions. Biotechniques 2007; 42:572, 574, 576. [PMID: 17515194 DOI: 10.2144/000112458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Yiwei Tony Zhu
- Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
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97
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Wu S, Ying G, Wu Q, Capecchi MR. Toward simpler and faster genome-wide mutagenesis in mice. Nat Genet 2007; 39:922-30. [PMID: 17572674 DOI: 10.1038/ng2060] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 05/04/2007] [Indexed: 01/31/2023]
Abstract
Here we describe a practical Cre-loxP and piggyBac transposon-based mutagenesis strategy to systematically mutate coding sequences and/or the vast noncoding regions of the mouse genome for large-scale functional genomic analysis. To illustrate this approach, we first created loxP-containing loss-of-function alleles in the protocadherin alpha, beta and gamma gene clusters (Pcdha, Pcdhb and Pcdhg). Using these alleles, we show that, under proper guidance, Cre-loxP site-specific recombination can mediate efficient trans-allelic recombination in vivo, facilitating the generation of large germline deletions and duplications including deletions of Pcdha, and Pcdha to Pcdhb, simply by breeding (that is, at frequencies of 5.5%-21.6%). The same breeding method can also generate designed germline translocations between nonhomologous chromosomes at unexpected frequencies of greater than 1%. By incorporating a piggyBac transposon to insert and to distribute loxP sites randomly throughout the mouse genome, we present a simple but comprehensive method for generating genome-wide deletions and duplications, in addition to insertional loss-of-function and conditional rescue alleles, again simply by breeding.
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Affiliation(s)
- Sen Wu
- Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah 84112, USA
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98
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Brault V, Besson V, Magnol L, Duchon A, Hérault Y. Cre/loxP-mediated chromosome engineering of the mouse genome. Handb Exp Pharmacol 2007:29-48. [PMID: 17203650 DOI: 10.1007/978-3-540-35109-2_2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Together with numerous other genome modifications, chromosome engineering offers a very powerful tool to accelerate the functional analysis of the mammalian genome. The technology, based on the Cre/loxP system, is used more and more in the scientific community in order to generate new chromosomes carrying deletions, duplications, inversions and translocations in targeted regions of interest. In this review, we will present the basic principle of the technique either in vivo or in vitro and we will briefly describe some applications to provide highly valuable genetic tools, to decipher the mammalian genome organisation and to analyze human diseases in the mouse.
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Affiliation(s)
- V Brault
- Institut de Transgénose, IEM, UMR6812, CNRS Uni-Orléans, 3B rue de la Férollerie, 45071 Orleans 2, France
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Brault V, Pereira P, Duchon A, Hérault Y. Modeling chromosomes in mouse to explore the function of genes, genomic disorders, and chromosomal organization. PLoS Genet 2006; 2:e86. [PMID: 16839184 PMCID: PMC1500809 DOI: 10.1371/journal.pgen.0020086] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
One of the challenges of genomic research after the completion of the human genome project is to assign a function to all the genes and to understand their interactions and organizations. Among the various techniques, the emergence of chromosome engineering tools with the aim to manipulate large genomic regions in the mouse model offers a powerful way to accelerate the discovery of gene functions and provides more mouse models to study normal and pathological developmental processes associated with aneuploidy. The combination of gene targeting in ES cells, recombinase technology, and other techniques makes it possible to generate new chromosomes carrying specific and defined deletions, duplications, inversions, and translocations that are accelerating functional analysis. This review presents the current status of chromosome engineering techniques and discusses the different applications as well as the implication of these new techniques in future research to better understand the function of chromosomal organization and structures.
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Affiliation(s)
- Véronique Brault
- Institut de Transgénose, IEM, CNRS Uni Orléans, UMR6218, Orléans, France
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100
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Khor B, Bredemeyer AL, Huang CY, Turnbull IR, Evans R, Maggi LB, White JM, Walker LM, Carnes K, Hess RA, Sleckman BP. Proteasome activator PA200 is required for normal spermatogenesis. Mol Cell Biol 2006; 26:2999-3007. [PMID: 16581775 PMCID: PMC1446934 DOI: 10.1128/mcb.26.8.2999-3007.2006] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 01/28/2006] [Accepted: 01/30/2006] [Indexed: 11/20/2022] Open
Abstract
The PA200 proteasome activator is a broadly expressed nuclear protein. Although how PA200 normally functions is not fully understood, it has been suggested to be involved in the repair of DNA double-strand breaks (DSBs). The PA200 gene (Psme4) is composed of 45 coding exons spanning 108 kb on mouse chromosome 11. We generated a PA200 null allele (PA200(Delta)) through Cre-loxP-mediated interchromosomal recombination after targeting loxP sites at either end of the locus. PA200(Delta/Delta) mice are viable and have no obvious developmental abnormalities. Both lymphocyte development and immunoglobulin class switching, which rely on the generation and repair of DNA DSBs, are unperturbed in PA200(Delta/Delta) mice. Additionally, PA200(Delta/Delta) embryonic stem cells do not exhibit increased sensitivity to either ionizing radiation or bleomycin. Thus, PA200 is not essential for the repair of DNA DSBs generated in these settings. Notably, loss of PA200 led to a marked reduction in male, but not female, fertility. This was due to defects in spermatogenesis observed in meiotic spermatocytes and during the maturation of postmeiotic haploid spermatids. Thus, PA200 serves an important nonredundant function during spermatogenesis, suggesting that the efficient generation of male gametes has distinct protein metabolic requirements.
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Affiliation(s)
- Bernard Khor
- Department of Pathology and Immunology, Campus Box 8118, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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