1
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Cre-Controlled CRISPR mutagenesis provides fast and easy conditional gene inactivation in zebrafish. Nat Commun 2021; 12:1125. [PMID: 33602923 PMCID: PMC7893016 DOI: 10.1038/s41467-021-21427-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
Conditional gene inactivation is a powerful tool to determine gene function when constitutive mutations result in detrimental effects. The most commonly used technique to achieve conditional gene inactivation employs the Cre/loxP system and its ability to delete DNA sequences flanked by two loxP sites. However, targeting a gene with two loxP sites is time and labor consuming. Here, we show Cre-Controlled CRISPR (3C) mutagenesis to circumvent these issues. 3C relies on gRNA and Cre-dependent Cas9-GFP expression from the same transgene. Exogenous or transgenic supply of Cre results in Cas9-GFP expression and subsequent mutagenesis of the gene of interest. The recombined cells become fluorescently visible enabling their isolation and subjection to various omics techniques. Hence, 3C mutagenesis provides a valuable alternative to the production of loxP-flanked alleles. It might even enable the conditional inactivation of multiple genes simultaneously and should be applicable to other model organisms amenable to single integration transgenesis. Targeting a gene with two loxP sites is both time and labour intensive. Here the authors present Cre-Controlled CRISPR allowing conditional mutagenesis of a gene of interest and simultaneously labelling the putative mutant cells fluorescently.
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2
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Heat-shock-induced tyrosinase gene ablation with CRISPR in zebrafish. Mol Genet Genomics 2020; 295:911-922. [PMID: 32367255 DOI: 10.1007/s00438-020-01681-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/23/2020] [Indexed: 01/05/2023]
Abstract
Tyrosinase (TYR) converts L-tyrosine into 3,4-dihydroxyphenylalanine (L-DOPA) and L-DOPA into L-dopaquinone, which can produce melanin pigment. The abrogation of the functional activity of TYR can result in albino skin and eye diseases because of a deficiency in melanin pigment production. In this study, we developed and characterized an inducible knockout TYR platform comprising the heat-inducible heat-shock-promoter-70-driving CRISPR/Cas9 system and a zU6-promoter-driving tyr single guide RNA (sgRNA) system to investigate the temporal expression of TYR genes. To overcome the difficulty of identifying zebrafish germline integrations and facilitate the observation of Cas9 expression, heart-specific cmlc2:enhanced green fluorescent protein (EGFP; used to confirm tyr sgRNA expression) and two selectable markers (P2A-mCherry and internal ribosomal entry site-EGFP) were applied in our system. Heat shock treatment administered to Cas9 transgenic embryos induced mCherry or EGFP fluorescence expression throughout the embryos' bodies, and Cas9 protein was detected 1 h after heat shock treatment. Mutations were created by direct injection and line crossing, which led to mosaic and complete depigmentation phenotypes in approximately 50% and 100% of the embryos, respectively. Using our system, conditional TYR knockout in zebrafish was achieved efficiently and simply.
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3
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Li X, Yu S, Lee Y, Guo T, Kwon N, Lee D, Yeom SC, Cho Y, Kim G, Huang JD, Choi S, Nam KT, Yoon J. In Vivo Albumin Traps Photosensitizer Monomers from Self-Assembled Phthalocyanine Nanovesicles: A Facile and Switchable Theranostic Approach. J Am Chem Soc 2018; 141:1366-1372. [DOI: 10.1021/jacs.8b12167] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Xingshu Li
- College of Chemistry, State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou 350108, China
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Sungsook Yu
- Severance Biomedical Science Institute, Brain Korea 21 PLUS Project for Medical Science, College of Medicine, Yonsei University, Seoul 03760, Republic of Korea
| | - Yoonji Lee
- College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Tian Guo
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Nahyun Kwon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Dayoung Lee
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Su Cheong Yeom
- Graduate School of International Agricultural Technology, Seoul National University, 1447 Pyeongchang-Ro, Daewha, Pyeongchang, Gangwon 25354, Republic of Korea
| | - Yejin Cho
- Severance Biomedical Science Institute, Brain Korea 21 PLUS Project for Medical Science, College of Medicine, Yonsei University, Seoul 03760, Republic of Korea
| | - Gyoungmi Kim
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jian-Dong Huang
- College of Chemistry, State Key Laboratory of Photocatalysis on Energy and Environment, Fujian Provincial Key Laboratory of Cancer Metastasis Chemoprevention and Chemotherapy, Fuzhou University, Fuzhou 350108, China
| | - Sun Choi
- College of Pharmacy and Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Ki Taek Nam
- Severance Biomedical Science Institute, Brain Korea 21 PLUS Project for Medical Science, College of Medicine, Yonsei University, Seoul 03760, Republic of Korea
| | - Juyoung Yoon
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 03760, Republic of Korea
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4
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Lehners M, Dobrowinski H, Feil S, Feil R. cGMP Signaling and Vascular Smooth Muscle Cell Plasticity. J Cardiovasc Dev Dis 2018; 5:jcdd5020020. [PMID: 29671769 PMCID: PMC6023364 DOI: 10.3390/jcdd5020020] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 12/11/2022] Open
Abstract
Cyclic GMP regulates multiple cell types and functions of the cardiovascular system. This review summarizes the effects of cGMP on the growth and survival of vascular smooth muscle cells (VSMCs), which display remarkable phenotypic plasticity during the development of vascular diseases, such as atherosclerosis. Recent studies have shown that VSMCs contribute to the development of atherosclerotic plaques by clonal expansion and transdifferentiation to macrophage-like cells. VSMCs express a variety of cGMP generators and effectors, including NO-sensitive guanylyl cyclase (NO-GC) and cGMP-dependent protein kinase type I (cGKI), respectively. According to the traditional view, cGMP inhibits VSMC proliferation, but this concept has been challenged by recent findings supporting a stimulatory effect of the NO-cGMP-cGKI axis on VSMC growth. Here, we summarize the relevant studies with a focus on VSMC growth regulation by the NO-cGMP-cGKI pathway in cultured VSMCs and mouse models of atherosclerosis, restenosis, and angiogenesis. We discuss potential reasons for inconsistent results, such as the use of genetic versus pharmacological approaches and primary versus subcultured cells. We also explore how modern methods for cGMP imaging and cell tracking could help to improve our understanding of cGMP’s role in vascular plasticity. We present a revised model proposing that cGMP promotes phenotypic switching of contractile VSMCs to VSMC-derived plaque cells in atherosclerotic lesions. Regulation of vascular remodeling by cGMP is not only an interesting new therapeutic strategy, but could also result in side effects of clinically used cGMP-elevating drugs.
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Affiliation(s)
- Moritz Lehners
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
| | - Hyazinth Dobrowinski
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
| | - Susanne Feil
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
| | - Robert Feil
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany.
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5
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Thunemann M, Schörg BF, Feil S, Lin Y, Voelkl J, Golla M, Vachaviolos A, Kohlhofer U, Quintanilla-Martinez L, Olbrich M, Ehrlichmann W, Reischl G, Griessinger CM, Langer HF, Gawaz M, Lang F, Schäfers M, Kneilling M, Pichler BJ, Feil R. Cre/lox-assisted non-invasive in vivo tracking of specific cell populations by positron emission tomography. Nat Commun 2017; 8:444. [PMID: 28874662 PMCID: PMC5585248 DOI: 10.1038/s41467-017-00482-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 07/03/2017] [Indexed: 01/15/2023] Open
Abstract
Many pathophysiological processes are associated with proliferation, migration or death of distinct cell populations. Monitoring specific cell types and their progeny in a non-invasive, longitudinal and quantitative manner is still challenging. Here we show a novel cell-tracking system that combines Cre/lox-assisted cell fate mapping with a thymidine kinase (sr39tk) reporter gene for cell detection by positron emission tomography (PET). We generate Rosa26-mT/sr39tk PET reporter mice and induce sr39tk expression in platelets, T lymphocytes or cardiomyocytes. As proof of concept, we demonstrate that our mouse model permits longitudinal PET imaging and quantification of T-cell homing during inflammation and cardiomyocyte viability after myocardial infarction. Moreover, Rosa26-mT/sr39tk mice are useful for whole-body characterization of transgenic Cre mice and to detect previously unknown Cre activity. We anticipate that the Cre-switchable PET reporter mice will be broadly applicable for non-invasive long-term tracking of selected cell populations in vivo.Non-invasive cell tracking is a powerful method to visualize cells in vivo under physiological and pathophysiological conditions. Here Thunemann et al. generate a mouse model for in vivo tracking and quantification of specific cell types by combining a PET reporter gene with Cre-dependent activation that can be exploited for any cell population for which a Cre mouse line is available.
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Affiliation(s)
- Martin Thunemann
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany.,Department of Radiology, University of California San Diego, La Jolla, CA, USA
| | - Barbara F Schörg
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany
| | - Susanne Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany
| | - Yun Lin
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany
| | - Jakob Voelkl
- Physiologisches Institut I, University of Tübingen, 72076 Tübingen, Germany
| | - Matthias Golla
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany
| | - Angelos Vachaviolos
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany
| | - Ursula Kohlhofer
- Institute of Pathology and Neuropathology, University of Tübingen, and Comprehensive Cancer Center, University Hospital, 72076 Tübingen, Germany
| | - Leticia Quintanilla-Martinez
- Institute of Pathology and Neuropathology, University of Tübingen, and Comprehensive Cancer Center, University Hospital, 72076 Tübingen, Germany
| | - Marcus Olbrich
- Department of Cardiovascular Medicine, University Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Walter Ehrlichmann
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany
| | - Gerald Reischl
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany
| | - Christoph M Griessinger
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany
| | - Harald F Langer
- Department of Cardiovascular Medicine, University Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Meinrad Gawaz
- Department of Cardiovascular Medicine, University Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Florian Lang
- Physiologisches Institut I, University of Tübingen, 72076 Tübingen, Germany
| | - Michael Schäfers
- Department of Nuclear Medicine, University Hospital, European Institute for Molecular Imaging & EXC 1003 Cells-in-Motion Cluster of Excellence, University of Münster, 48149 Münster, Germany
| | - Manfred Kneilling
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany.,Department of Dermatology, University Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Bernd J Pichler
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, University of Tübingen, 72076 Tübingen, Germany
| | - Robert Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076 Tübingen, Germany.
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6
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Boyko TV, Longaker MT, Yang GP. Laboratory Models for the Study of Normal and Pathologic Wound Healing. Plast Reconstr Surg 2017; 139:654-662. [PMID: 28234843 DOI: 10.1097/prs.0000000000003077] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Current knowledge of wound healing is based on studies using various in vitro and in vivo wound models. In vitro models allow for biological examination of specific cell types involved in wound healing. In vivo models generally provide the full spectrum of biological responses required for wound healing, including inflammation and angiogenesis, and provide cell-cell interactions not seen in vitro. In this review, the authors aim to delineate the most relevant wound healing models currently available and to discuss their strengths and limitations in their approximation of the human wound healing processes to aid scientists in choosing the most appropriate wound healing models for designing, testing, and validating their experiments.
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Affiliation(s)
- Tatiana V Boyko
- Stanford and Palo Alto, Calif.; and Buffalo, N.Y.,From the Hagey Laboratory for Pediatric Regenerative Medicine, the Department of Surgery, and the Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine; the Palo Alto VA Health Care System; and the Department of Surgery, University at Buffalo, State University of New York
| | - Michael T Longaker
- Stanford and Palo Alto, Calif.; and Buffalo, N.Y.,From the Hagey Laboratory for Pediatric Regenerative Medicine, the Department of Surgery, and the Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine; the Palo Alto VA Health Care System; and the Department of Surgery, University at Buffalo, State University of New York
| | - George P Yang
- Stanford and Palo Alto, Calif.; and Buffalo, N.Y.,From the Hagey Laboratory for Pediatric Regenerative Medicine, the Department of Surgery, and the Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine; the Palo Alto VA Health Care System; and the Department of Surgery, University at Buffalo, State University of New York
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7
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Liljevald M, Rehnberg M, Söderberg M, Ramnegård M, Börjesson J, Luciani D, Krutrök N, Brändén L, Johansson C, Xu X, Bjursell M, Sjögren AK, Hornberg J, Andersson U, Keeling D, Jirholt J. Retinoid-related orphan receptor γ (RORγ) adult induced knockout mice develop lymphoblastic lymphoma. Autoimmun Rev 2016; 15:1062-1070. [DOI: 10.1016/j.autrev.2016.07.036] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 07/13/2016] [Indexed: 02/08/2023]
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8
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Abstract
Transgenesis is an essential tool to investigate gene function and to introduce desired characters in laboratory organisms. Setting-up transgenesis in non-model organisms is challenging due to the diversity of biological life traits and due to knowledge gaps in genomic information. Some procedures will be broadly applicable to many organisms, and others have to be specifically developed for the target species. Transgenesis in disease vector mosquitoes has existed since the 2000s but has remained limited by the delicate biology of these insects. Here, we report a compilation of the transgenesis tools that we have designed for the malaria vector Anopheles gambiae, including new docking strains, convenient transgenesis plasmids, a puromycin resistance selection marker, mosquitoes expressing cre recombinase, and various reporter lines defining the activity of cloned promoters. This toolbox contributed to rendering transgenesis routine in this species and is now enabling the development of increasingly refined genetic manipulations such as targeted mutagenesis. Some of the reagents and procedures reported here are easily transferable to other nonmodel species, including other disease vector or agricultural pest insects.
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9
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Faal T, Wong PT, Tang S, Coulter A, Chen Y, Tu CH, Baker JR, Choi SK, Inlay MA. 4-Hydroxytamoxifen probes for light-dependent spatiotemporal control of Cre-ER mediated reporter gene expression. MOLECULAR BIOSYSTEMS 2015; 11:783-90. [DOI: 10.1039/c4mb00581c] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Here, we synthesized and validated a photocaged hydroxytamoxifen molecule to achieve spatiotemporal control of gene expression with light.
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Affiliation(s)
- Tannaz Faal
- Sue and Bill Gross Stem Cell Research Center
- University of California Irvine
- Irvine
- USA
- Department of Molecular Biology and Biochemistry
| | - Pamela T. Wong
- Department of Internal Medicine
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Shengzhuang Tang
- Department of Internal Medicine
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Alexa Coulter
- Department of Internal Medicine
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Yumay Chen
- Sue and Bill Gross Stem Cell Research Center
- University of California Irvine
- Irvine
- USA
- Department of Medicine
| | - Christina H. Tu
- Sue and Bill Gross Stem Cell Research Center
- University of California Irvine
- Irvine
- USA
| | - James R. Baker
- Department of Internal Medicine
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Seok Ki Choi
- Department of Internal Medicine
- Michigan Nanotechnology Institute for Medicine and Biological Sciences
- University of Michigan
- Ann Arbor
- USA
| | - Matthew A. Inlay
- Sue and Bill Gross Stem Cell Research Center
- University of California Irvine
- Irvine
- USA
- Department of Molecular Biology and Biochemistry
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10
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Differential organ phenotypes after postnatal Igf1r gene conditional deletion induced by tamoxifen in UBC-CreERT2; Igf1r fl/fl double transgenic mice. Transgenic Res 2014; 24:279-94. [DOI: 10.1007/s11248-014-9837-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/09/2014] [Indexed: 11/25/2022]
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11
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Fleet JC. Animal models of gastrointestinal and liver diseases. New mouse models for studying dietary prevention of colorectal cancer. Am J Physiol Gastrointest Liver Physiol 2014; 307:G249-59. [PMID: 24875098 PMCID: PMC4121636 DOI: 10.1152/ajpgi.00019.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Colorectal cancer is a heterogeneous disease that is one of the major causes of cancer death in the U.S. There is evidence that lifestyle factors like diet can modulate the course of this disease. Demonstrating the benefit and mechanism of action of dietary interventions against colon cancer will require studies in preclinical models. Many mouse models have been developed to study colon cancer but no single model can reflect all types of colon cancer in terms of molecular etiology. In addition, many models develop only low-grade cancers and are confounded by development of the disease outside of the colon. This review will discuss how mice can be used to model human colon cancer and it will describe a variety of new mouse models that develop colon-restricted cancer as well as more advanced phenotypes for studies of late-state disease.
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Affiliation(s)
- James C. Fleet
- 1Department of Nutrition Science, Purdue University, West Lafayette, Indiana; and ,2Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana
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12
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All-in-One inducible lentiviral vector systems based on drug controlled FLP recombinase. Biomaterials 2014; 35:4345-56. [DOI: 10.1016/j.biomaterials.2014.01.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 01/23/2014] [Indexed: 01/11/2023]
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13
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Genetic inducible fate mapping in adult mice using tamoxifen-dependent Cre recombinases. Methods Mol Biol 2014; 1194:113-39. [PMID: 25064100 DOI: 10.1007/978-1-4939-1215-5_6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The Cre/lox site-specific recombination system allows the control of gene activity in space and time in almost any tissue of the mouse. A major technical advance was the development of tamoxifen-dependent Cre recombinases, such as CreER(T2), that can be activated by administration of tamoxifen to the animal. This powerful tool greatly facilitates the study of gene functions and the generation of more realistic animal models of sporadic human diseases. Another important application of tamoxifen-dependent Cre recombinases is genetic inducible fate mapping (GIFM). In GIFM studies, the inducible Cre/lox system is used to genetically label a defined cell population at a selected time by irreversible activation of the expression of a Cre-responsive reporter transgene. Then, marked cells are detected at later time points to determine how the originally labeled progenitors contribute to specific structures and cell types during pre- and postnatal development. GIFM was initially applied during mouse embryogenesis, but is now increasingly used for cell lineage tracing in adult mice under physiological and pathophysiological conditions. Here we describe the design of GIFM experiments in adult mice as exemplified by CreER(T2)-assisted tracing of vascular smooth muscle cells during the development of atherosclerotic lesions. First, we give an overview of reporter transgenes available for genetic cell marking that are expressed from the Rosa26 locus, such as β-galactosidase and fluorescent proteins. Then we present detailed protocols for the generation of experimental mice for GIFM studies, the induction of cell labeling by tamoxifen treatment, and the detection of marked cells in fixed and live tissues. Each section also provides a discussion of limitations and common pitfalls of GIFM experiments. Most of the protocols can be easily adapted to other developmental stages, cell types, Cre recombinases, and reporter transgenes and, thus, can be used as general guidelines for GIFM studies in mice.
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14
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Abstract
Zebrafish has become a widely used model for analysis of gene function. Several methods have been used to create mutations in this organism and thousands of mutant lines are available. However, all the conventional zebrafish mutations affect the gene in all cells at all time, making it difficult to determine tissue-specific functions. We have adopted a FlEx Trap approach to generate conditional mutations in zebrafish by gene-trap mutagenesis. Combined with appropriate Cre or Flp lines, the insertional mutants not only allow spatial- and temporal-specific gene inactivation but also permit spatial- and temporal-specific rescue of the disrupted gene. We provide experimental details on how to generate and use such mutations.
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Affiliation(s)
- Lisette A Maddison
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
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15
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Kraus P, Sivakamasundari V, Xing X, Lufkin T. Generating mouse lines for lineage tracing and knockout studies. Methods Mol Biol 2014; 1194:37-62. [PMID: 25064097 DOI: 10.1007/978-1-4939-1215-5_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In 2007 Capecchi, Evans, and Smithies received the Nobel Prize in recognition for discovering the principles for introducing specific gene modifications in mice via embryonic stem cells, a technology, which has revolutionized the field of biomedical science allowing for the generation of genetically engineered animals. Here we describe detailed protocols based on and developed from these ground-breaking discoveries, allowing for the modification of genes not only to create mutations to study gene function but additionally to modify genes with fluorescent markers, thus permitting the isolation of specific rare wild-type and mutant cell types for further detailed analysis at the biochemical, pathological, and genomic levels.
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Affiliation(s)
- Petra Kraus
- Department of Biology, Clarkson University, Potsdam, 13699-5808, USA
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16
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Abstract
Colorectal cancer is a heterogeneous disease that afflicts a large number of people in the USA. The use of animal models has the potential to increase our understanding of carcinogenesis, tumor biology, and the impact of specific molecular events on colon biology. In addition, animal models with features of specific human colorectal cancers can be used to test strategies for cancer prevention and treatment. In this review, we provide an overview of the mechanisms driving human cancer, we discuss the approaches one can take to model colon cancer in animals, and we describe a number of specific animal models that have been developed for the study of colon cancer. We believe that there are many valuable animal models to study various aspects of human colorectal cancer. However, opportunities for improving upon these models exist.
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17
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Inlay MA, Choe V, Bharathi S, Fernhoff NB, Baker JR, Weissman IL, Choi SK. Synthesis of a photocaged tamoxifen for light-dependent activation of Cre-ER recombinase-driven gene modification. Chem Commun (Camb) 2013; 49:4971-3. [PMID: 23612712 PMCID: PMC3926663 DOI: 10.1039/c3cc42179a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We report the design of a water-soluble, quaternized tamoxifen photoprobe and demonstrate its application in light-controlled induction of green fluorescent protein expression via a Cre-ER recombinase system.
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Affiliation(s)
- Matthew A. Inlay
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Veronica Choe
- Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sophia Bharathi
- Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nathaniel B. Fernhoff
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - James R. Baker
- Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Irving L. Weissman
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Seok Ki Choi
- Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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18
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Shen MC, Ozacar AT, Osgood M, Boeras C, Pink J, Thomas J, Kohtz JD, Karlstrom R. Heat-shock-mediated conditional regulation of hedgehog/gli signaling in zebrafish. Dev Dyn 2013; 242:539-49. [PMID: 23441066 DOI: 10.1002/dvdy.23955] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Revised: 12/16/2012] [Accepted: 01/14/2013] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Hedgehog (Hh) signaling is required for embryogenesis and continues to play key roles postembryonically in many tissues, influencing growth, stem cell proliferation, and tumorigenesis. Systems for conditional regulation of Hh signaling facilitate the study of these postembryonic Hh functions. RESULTS We used the hsp70l promoter to generated three heat-shock-inducible transgenic lines that activate Hh signaling and one line that represses Hh signaling. Heat-shock activation of these transgenes appropriately recapitulates early embryonic loss or gain of Hh function phenotypes. Hh signaling remains activated 24 hr after heat shock in the Tg(hsp70l:shha-EGFP) and Tg(hsp70l:dnPKA-BGFP) lines, while a single heat shock of the Tg(hsp70l:gli1-EGFP) or Tg(hsp70l:gli2aDR-EGFP) lines results in a 6- to 12-hr pulse of Hh signal activation or inactivation, respectively. Using both in situ hybridization and quantitative polymerase chain reaction, we show that these lines can be used to manipulate Hh signaling through larval and juvenile stages. A ptch2 promoter element was used to generate new reporter lines that allow clear visualization of Hh responding cells throughout the life cycle, including graded Hh responses in the embryonic central nervous system. CONCLUSIONS These zebrafish transgenic lines provide important new experimental tools to study the embryonic and postembryonic roles of Hh signaling.
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Affiliation(s)
- Meng-Chieh Shen
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Shi W, Bain AL, Schwer B, Al-Ejeh F, Smith C, Wong L, Chai H, Miranda MS, Ho U, Kawaguchi M, Miura Y, Finnie JW, Wall M, Heierhorst J, Wicking C, Spring KJ, Alt FW, Khanna KK. Essential developmental, genomic stability, and tumour suppressor functions of the mouse orthologue of hSSB1/NABP2. PLoS Genet 2013; 9:e1003298. [PMID: 23408915 PMCID: PMC3567186 DOI: 10.1371/journal.pgen.1003298] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 12/16/2012] [Indexed: 12/15/2022] Open
Abstract
Single-stranded DNA binding proteins (SSBs) regulate multiple DNA transactions, including replication, transcription, and repair. We recently identified SSB1 as a novel protein critical for the initiation of ATM signaling and DNA double-strand break repair by homologous recombination. Here we report that germline Ssb1(-/-) embryos die at birth from respiratory failure due to severe rib cage malformation and impaired alveolar development, coupled with additional skeletal defects. Unexpectedly, Ssb1(-/-) fibroblasts did not exhibit defects in Atm signaling or γ-H2ax focus kinetics in response to ionizing radiation (IR), and B-cell specific deletion of Ssb1 did not affect class-switch recombination in vitro. However, conditional deletion of Ssb1 in adult mice led to increased cancer susceptibility with broad tumour spectrum, impaired male fertility with testicular degeneration, and increased radiosensitivity and IR-induced chromosome breaks in vivo. Collectively, these results demonstrate essential roles of Ssb1 in embryogenesis, spermatogenesis, and genome stability in vivo.
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Affiliation(s)
- Wei Shi
- Queensland Institute of Medical Research, Herston, Australia
| | - Amanda L. Bain
- Queensland Institute of Medical Research, Herston, Australia
- School of Biomolecular and Physical Sciences, Griffith University, Nathan, Australia
| | - Bjoern Schwer
- Howard Hughes Medical Institute, Immune Disease Institute, Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Genetics and Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Fares Al-Ejeh
- Queensland Institute of Medical Research, Herston, Australia
| | - Corey Smith
- Queensland Institute of Medical Research, Herston, Australia
| | - Lee Wong
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia
| | - Hua Chai
- Howard Hughes Medical Institute, Immune Disease Institute, Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Genetics and Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mariska S. Miranda
- Queensland Institute of Medical Research, Herston, Australia
- School of Medicine, University of Queensland, Herston, Australia
| | - Uda Ho
- Queensland Institute of Medical Research, Herston, Australia
| | - Makoto Kawaguchi
- Department of Bioregulation and Molecular Neurobiology, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan
| | - Yutaka Miura
- Department of Bioregulation and Molecular Neurobiology, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan
| | - John W. Finnie
- SA Pathology, Institute of Medical and Veterinary Science, Adelaide, Australia
| | - Meaghan Wall
- Victorian Cancer Cytogenetics Service, St. Vincent's Hospital, Fitzroy, Melbourne, Australia
- Department of Medicine, St. Vincent's Hospital, Fitzroy, Australia
| | - Jörg Heierhorst
- Department of Medicine, St. Vincent's Hospital, Fitzroy, Australia
- St. Vincent's Institute, Fitzroy, Australia
| | - Carol Wicking
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Kevin J. Spring
- Queensland Institute of Medical Research, Herston, Australia
- School of Biomolecular and Physical Sciences, Griffith University, Nathan, Australia
- School of Medicine, University of Queensland, Herston, Australia
| | - Frederick W. Alt
- Howard Hughes Medical Institute, Immune Disease Institute, Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, Massachusetts, United States of America
- Department of Genetics and Pediatrics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kum Kum Khanna
- Queensland Institute of Medical Research, Herston, Australia
- School of Biomolecular and Physical Sciences, Griffith University, Nathan, Australia
- School of Medicine, University of Queensland, Herston, Australia
- * E-mail:
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Shapiro MG, Frazier SJ, Lester HA. Unparalleled control of neural activity using orthogonal pharmacogenetics. ACS Chem Neurosci 2012; 3:619-29. [PMID: 22896806 DOI: 10.1021/cn300053q] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/01/2012] [Indexed: 11/28/2022] Open
Abstract
Studying the functional architecture of the brain requires technologies to precisely measure and perturb the activity of specific neural cells and circuits in live animals. Substantial progress has been made in recent years to develop and apply such tools. In particular, technologies that provide precise control of activity in genetically defined populations of neurons have enabled the study of causal relationships between and among neural circuit elements and behavioral outputs. Here, we review an important subset of such technologies, in which neurons are genetically engineered to respond to specific chemical ligands that have no interfering pharmacological effect in the central nervous system. A rapidly expanding set of these "orthogonal pharmacogenetic" tools provides a unique combination of genetic specificity, functional diversity, spatiotemporal precision, and potential for multiplexing. We review the main classes of orthogonal pharmacogenetic technologies, including neuroreceptors to control neuronal excitability, systems to control gene transcription and translation, and general constructs to control protein-protein interactions, enzymatic function, and protein stability. We describe the key performance characteristics informing the use of these technologies in the brain, and potential directions for improvement and expansion of the orthogonal pharmacogenetics toolkit to enable more sophisticated systems neuroscience.
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Affiliation(s)
- Mikhail G. Shapiro
- Miller Research Institute, Department
of Bioengineering, and Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California
94720, United States
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Production of avian retroviruses and tissue-specific somatic retroviral gene transfer in vivo using the RCAS/TVA system. Nat Protoc 2012; 7:1167-83. [DOI: 10.1038/nprot.2012.060] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Pfrieger FW, Slezak M. Genetic approaches to study glial cells in the rodent brain. Glia 2011; 60:681-701. [PMID: 22162024 DOI: 10.1002/glia.22283] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/18/2011] [Indexed: 01/02/2023]
Abstract
The development, function, and pathology of the brain depend on interactions of neurons and different types of glial cells, namely astrocytes, oligodendrocytes, microglia, and ependymal cells. Understanding neuron-glia interactions in vivo requires dedicated experimental approaches to manipulate each cell type independently. In this review, we first summarize techniques that allow for cell-specific gene modification including targeted mutagenesis and viral transduction. In the second part, we describe the genetic models that allow to target the main glial cell types in the central nervous system. The existing arsenal of approaches to study glial cells in vivo and its expansion in the future are key to understand neuron-glia interactions under normal and pathologic conditions.
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Affiliation(s)
- Frank W Pfrieger
- CNRS UPR 3212, University of Strasbourg, Institute of Cellular and Integrative Neurosciences (INCI), 67084 Strasbourg, France.
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Vanbrocklin MW, Robinson JP, Lastwika KJ, McKinney AJ, Gach HM, Holmen SL. Ink4a/Arf loss promotes tumor recurrence following Ras inhibition. Neuro Oncol 2011; 14:34-42. [PMID: 22015595 DOI: 10.1093/neuonc/nor184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Aberrant activation of rat sarcoma (Ras) signaling contributes to the development of a variety of human cancers, including gliomas. To determine the dependence of high-grade gliomas on continued Ras signaling, we developed a doxycycline-regulated Kirsten Ras (KRas) glioma mouse model. We previously demonstrated that KRas is required for the maintenance of glioblastoma multiforme tumors arising in the context of activated Akt signaling in vivo; inhibition of KRas expression resulted in apoptotic tumor regression and significantly increased survival. We utilized a well-established glioma mouse model to determine the reliance of gliomas on continued KRas signaling in the context of Ink4a/Arf deficiency, a common occurrence in human gliomas. Despite the dependency of primary gliomas on continued KRas signaling, a significant percentage of tumors progressed to a KRas-independent state in the absence of Ink4a/Arf expression, demonstrating that these tumor suppressors play a critical role in the suppression of glioma recurrence. While even advanced stages of gliomas may remain dependent upon KRas signaling for maintenance and growth, our findings demonstrate that loss of Ink4a/Arf facilitates the acquisition of oncogene independence and tumor recurrence. Furthermore, reactivation of the Ras mitogen-activated protein kinase pathway in the absence of virally delivered KRas expression is a common mechanism of recurrence in this context.
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Herrmann S, Ludwig A. Not so fast! Sick sinus syndrome is a complex and incompletely understood disease that might prove hard to model in animals: reply. Cardiovasc Res 2011. [DOI: 10.1093/cvr/cvr205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie Medizinische Fakultät Friedrich-Alexander-Universität Erlangen-Nürnberg Fahrstr. 17 91054 Erlangen Germany
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie Medizinische Fakultät Friedrich-Alexander-Universität Erlangen-Nürnberg Fahrstr. 17 91054 Erlangen Germany
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Ishikawa TO, Herschman HR. Conditional bicistronic Cre reporter line expressing both firefly luciferase and β-galactosidase. Mol Imaging Biol 2011; 13:284-92. [PMID: 20495880 PMCID: PMC3051074 DOI: 10.1007/s11307-010-0333-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Purpose The Cre-loxP system has become an important strategy for conditional gene deletion and conditional gene expression in genetically engineered mice. To evaluate Cre recombinase expression, we generated reporter mice that permit both noninvasive imaging in living animals and either ex vivo histochemical/immunohistochemical tissue transgene expression analysis or quantitative enzyme analysis in the same animal. Procedures Transgenic reporter mice were generated in which a loxP-flanked enhanced green fluorescent protein (EGFP) reporter gene and STOP sequence are placed after the nearly ubiquitously expressed CAG promoter, but before a bicistronic transcriptional unit containing luciferase and β-galactosidase reporter gene coding sequences. Results After global deletion of the floxed STOP sequence by germ line Cre deletion, the reporter mouse expresses luciferase and β-galactosidase in all tissues examined. Tissue-specific expression of both reporter genes occurs in reporter mouse strains expressing Cre in skin (K14 keratin Cre), heart (myosin light chair Cre), or colon (Villin Cre). Conclusion The luc-galTg reporter mouse allows noninvasive imaging of target Cre activation both in living animals and in tissues and cells following necropsy, using loss of EGFP expression, gain of luciferase expression, and gain of β-galactosidase expression as alternatives within the same animal for qualitative analysis of Cre expression.
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Affiliation(s)
- Tomo-o Ishikawa
- Department of Molecular and Medical Pharmacology, Molecular Biology Institute, David Geffen School of Medicine, UCLA, 341 Boyer Hall, 611 Charles E. Young Drive East, Los Angeles, CA 90095, USA
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Metzger D, Chambon P. Generation of Spatio-Temporally Controlled Targeted Somatic Mutations in the Mouse. CURRENT PROTOCOLS IN MOUSE BIOLOGY 2011; 1:55-70. [PMID: 26068987 DOI: 10.1002/9780470942390.mo100128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The generation of ligand-activated site-specific Cre recombinases has led to the development of cell type-specific temporally controlled targeted somatic mutagenesis in the mouse. We illustrate this technique using K14-Cre-ER(T2) transgenic mice that express the tamoxifen (tam)-activatable Cre-ER(T2) recombinase in epidermal basal keratinocytes to induce mutations in epidermal keratinocytes of adult mice. Our highly reproducible technique, based on induction of Cre-ER(T2) recombinase activity by tamoxifen administration at low doses (once daily 100-µg intraperitoneal injection for 5 days), has allowed the generation of site-directed somatic mutations of numerous genes in mouse epidermal keratinocytes, and several mouse models of human diseases. The present step-by-step protocol describes how to introduce temporally controlled targeted mutations in epidermal keratinocytes of adult mice. Curr. Protoc. Mouse Biol. 1:55-70. © 2011 by John Wiley & Sons, Inc.
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Affiliation(s)
- Daniel Metzger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, and Collège de France, Illkirch, France
| | - Pierre Chambon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, and Collège de France, Illkirch, France
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Maddison LA, Lu J, Chen W. Generating conditional mutations in zebrafish using gene-trap mutagenesis. Methods Cell Biol 2011; 104:1-22. [PMID: 21924154 DOI: 10.1016/b978-0-12-374814-0.00001-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
While several mutagenesis methods have been successfully applied in zebrafish, these mutations do not allow tissue- or temporal-specific functional analysis. We have developed a strategy that will allow tissue- or temporal-specific disruption of genes in zebrafish. This strategy combines gene-trap mutagenesis and FlEx modules containing target sites for site-specific recombinases. The gene-trap cassette is highly mutagenic in one orientation and nonmutagenic in the opposite orientation, with different fluorescent proteins as indicators of the orientation. The inclusion of the FlEx modules allows two rounds of stable inversion mediated by the Cre and Flp recombinases. This gene-trap cassette can be easily delivered via transposons. Through large-scale community-wide efforts, broad genome coverage can be obtained. This should allow investigation of cell/tissue-specific gene function of a wide range of genes.
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Affiliation(s)
- Lisette A Maddison
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Alcantara Llaguno SR, Chen Y, McKay RM, Parada LF. Stem Cells in Brain Tumor Development. Curr Top Dev Biol 2011; 94:15-44. [DOI: 10.1016/b978-0-12-380916-2.00002-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Abstract
Reverse genetics consists in the modification of the activity of a target gene to analyse the phenotypic consequences. Four main approaches are used towards this goal and will be explained in this review. Two of them are centred on genome alterations. Mutations produced by random chemical or insertional mutagenesis can be screened to recover only mutants in a specific gene of interest. Alternatively, these alterations may be specifically targeted on a gene of interest by HR (homologous recombination). The other two approaches are centred on mRNA. RNA interference is a powerful method to reduce the level of gene products, while MO (morpholino) antisense oligonucleotides alter mRNA metabolism or translation. Some model species, such as Drosophila, are amenable to most of these approaches, whereas other model species are restricted to one of them. For example, in mice and yeasts, gene targeting by HR is prevalent, whereas in Xenopus and zebrafish MO oligonucleotides are mainly used. Genome-wide collections of mutants or inactivated models obtained in several species by these approaches have been made and will help decipher gene functions in the post-genomic era.
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Hans S, Freudenreich D, Geffarth M, Kaslin J, Machate A, Brand M. Generation of a non-leaky heat shock-inducible Cre line for conditional Cre/lox strategies in zebrafish. Dev Dyn 2010; 240:108-15. [DOI: 10.1002/dvdy.22497] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Liu Y, Suckale J, Masjkur J, Magro MG, Steffen A, Anastassiadis K, Solimena M. Tamoxifen-independent recombination in the RIP-CreER mouse. PLoS One 2010; 5:e13533. [PMID: 21063464 PMCID: PMC2965077 DOI: 10.1371/journal.pone.0013533] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 09/27/2010] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The inducible Cre-lox system is a valuable tool to study gene function in a spatial and time restricted fashion in mouse models. This strategy relies on the limited background activity of the modified Cre recombinase (CreER) in the absence of its inducer, the competitive estrogen receptor ligand, tamoxifen. The RIP-CreER mouse (Tg (Ins2-cre/Esr1) 1Dam) is among the few available β-cell specific CreER mouse lines and thus it has been often used to manipulate gene expression in the insulin-producing cells of the endocrine pancreas. PRINCIPAL FINDINGS Here, we report the detection of tamoxifen-independent Cre activity as early as 2 months of age in RIP-CreER mice crossed with three distinct reporter strains. SIGNIFICANCE Evidence of Cre-mediated recombination of floxed alleles even in the absence of tamoxifen administration should warrant cautious use of this mouse for the study of pancreatic β-cells.
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Affiliation(s)
- Yanmei Liu
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jakob Suckale
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
| | - Jimmy Masjkur
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
| | - Maria Grazia Magro
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Anja Steffen
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
- Medical Clinic III, University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
| | - Konstantinos Anastassiadis
- Genetic Engineering of Stem Cells, BioInnovations Zentrum, Dresden University of Technology, Dresden, Germany
- Center for Regenerative Therapies Dresden, Dresden University of Technology, Dresden, Germany
| | - Michele Solimena
- Molecular Diabetology, Paul Langerhans Institute Dresden, School of Medicine and University Clinic ‘Carl Gustav Carus’, Dresden University of Technology, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Regenerative Therapies Dresden, Dresden University of Technology, Dresden, Germany
- * E-mail:
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Scholten D, Österreicher CH, Scholten A, Iwaisako K, Gu G, Brenner DA, Kisseleva T. Genetic labeling does not detect epithelial-to-mesenchymal transition of cholangiocytes in liver fibrosis in mice. Gastroenterology 2010; 139:987-98. [PMID: 20546735 PMCID: PMC2930026 DOI: 10.1053/j.gastro.2010.05.005] [Citation(s) in RCA: 187] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 05/04/2010] [Accepted: 05/11/2010] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS Chronic injury changes the fate of certain cellular populations, inducing epithelial cells to generate fibroblasts by epithelial-to-mesenchymal transition (EMT) and mesenchymal cells to generate epithelial cells by mesenchymal-to-epithelial transition (MET). Although contribution of EMT/MET to embryogenesis, renal fibrosis, and lung fibrosis is well documented, role of EMT/MET in liver fibrosis is unclear. We determined whether cytokeratin-19 positive (K19(+)) cholangiocytes give rise to myofibroblasts (EMT) and/or whether glial fibrillary acidic protein positive (GFAP(+)) hepatic stellate cells (HSCs) can express epithelial markers (MET) in response to experimental liver injury. METHODS EMT was studied with Cre-loxP system to map cell fate of K19(+) cholangiocytes in K19(YFP) or fibroblast-specific protein-1 (FSP-1)(YFP) mice, generated by crossing tamoxifen-inducible K19(CreERT) mice or FSP-1(Cre) mice with Rosa26(f/f-YFP) mice. MET of GFAP(+) HSCs was studied in GFAP(GFP) mice. Mice were subjected to bile duct ligation or CCl(4)-liver injury, and livers were analyzed for expression of mesodermal and epithelial markers. RESULTS On Cre-loxP recombination, >40% of genetically labeled K19(+) cholangiocytes expressed yellow fluorescent protein (YFP). All mice developed liver fibrosis. However, specific immunostaining of K19(YFP) cholangiocytes showed no expression of EMT markers alpha-smooth muscle actin, desmin, or FSP-1. Moreover, cells genetically labeled by FSP-1(YFP) expression did not coexpress cholangiocyte markers K19 or E-cadherin. Genetically labeled GFAP(GFP) HSCs did not express epithelial or liver progenitor markers in response to liver injury. CONCLUSION EMT of cholangiocytes identified by genetic labeling does not contribute to hepatic fibrosis in mice. Likewise, GFAP(Cre)-labeled HSCs showed no coexpression of epithelial markers, providing no evidence for MET in HSCs in response to fibrogenic liver injury.
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Affiliation(s)
- David Scholten
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA,Dept. of Medicine III, University Hospital Aachen, Aachen, Germany
| | | | - Anjali Scholten
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Keiko Iwaisako
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Guoqiang Gu
- Dept. of Cell and Developmental Biology, Vanderbilt University, Medical Center, Nashville Tennessee, USA
| | - David A. Brenner
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Tatiana Kisseleva
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA,Correspondence: , Tel:1-858-822-5339
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Production of p53 gene knockout rats by homologous recombination in embryonic stem cells. Nature 2010; 467:211-3. [PMID: 20703227 PMCID: PMC2937076 DOI: 10.1038/nature09368] [Citation(s) in RCA: 209] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 07/26/2010] [Indexed: 01/10/2023]
Abstract
The use of homologous recombination to modify genes in embryonic stem (ES) cells provides a powerful means to elucidate gene function and create disease models1. Application of this technology to engineer genes in rats has previously been impossible in the absence of germline competent ES cells in this species. We have recently established authentic rat ES cells2, 3. Here we report the generation of the first gene knockout rats using the ES cell-based gene targeting technology. We designed a targeting vector to disrupt the tumor suppressor gene p53 (also known as Tp53) in rat ES cells via homologous recombination. p53 gene-targeted rat ES cells can be routinely generated. Furthermore, the p53 gene-targeted mutation in the rat ES cell genome can transmit through the germline via ES cell-rat chimeras to create p53 gene knockout rats. The rat is the most widely used animal model other than humans in biological research4–7. The establishment of gene targeting technology in rat ES cells, in combination with advances in genomics and the vast amount of research data on physiology and pharmacology in this species, now provides a powerful new platform for the study of human disease.
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Placinta M, Shen MC, Achermann M, Karlstrom RO. A laser pointer driven microheater for precise local heating and conditional gene regulation in vivo. Microheater driven gene regulation in zebrafish. BMC DEVELOPMENTAL BIOLOGY 2009; 9:73. [PMID: 20042114 PMCID: PMC2810295 DOI: 10.1186/1471-213x-9-73] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 12/30/2009] [Indexed: 01/02/2023]
Abstract
Background Tissue heating has been employed to study a variety of biological processes, including the study of genes that control embryonic development. Conditional regulation of gene expression is a particularly powerful approach for understanding gene function. One popular method for mis-expressing a gene of interest employs heat-inducible heat shock protein (hsp) promoters. Global heat shock of hsp-promoter-containing transgenic animals induces gene expression throughout all tissues, but does not allow for spatial control. Local heating allows for spatial control of hsp-promoter-driven transgenes, but methods for local heating are cumbersome and variably effective. Results We describe a simple, highly controllable, and versatile apparatus for heating biological tissue and other materials on the micron-scale. This microheater employs micron-scale fiber optics and uses an inexpensive laser-pointer as a power source. Optical fibers can be pulled on a standard electrode puller to produce tips of varying sizes that can then be used to reliably heat 20-100 μm targets. We demonstrate precise spatiotemporal control of hsp70l:GFP transgene expression in a variety of tissue types in zebrafish embryos and larvae. We also show how this system can be employed as part of a new method for lineage tracing that would greatly facilitate the study of organogenesis and tissue regulation at any time in the life cycle. Conclusion This versatile and simple local heater has broad utility for the study of gene function and for lineage tracing. This system could be used to control hsp-driven gene expression in any organism simply by bringing the fiber optic tip in contact with the tissue of interest. Beyond these uses for the study of gene function, this device has wide-ranging utility in materials science and could easily be adapted for therapeutic purposes in humans.
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Affiliation(s)
- Mike Placinta
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA.
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O'Connor AK, Kesterson RA, Yoder BK. Generating conditional mutants to analyze ciliary functions: the use of Cre-lox technology to disrupt cilia in specific organs. Methods Cell Biol 2009; 93:305-30. [PMID: 20409823 DOI: 10.1016/s0091-679x(08)93015-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The list of human disordered associated with cilia dysfunction, the ciliopathies, continues to highlight the importance of understanding the many roles of the long overlooked primary cilium. Much of the insights into the clinical importance of the cilium have come from analyses in model organisms, especially the mouse. However, the early embryonic lethality and severe developmental defects associated with cilia disruption has hindered progress in exploring cilia functions in late development or in adult tissues. This hurdle is being surmounted through the use of conditional alleles of genes encoding ciliary proteins and Cre deletor lines with inducible Cre activity or with lines expressing Cre in a cell-type-specific manner. Results from these approaches are providing important insights into the diverse array of cellular and tissue activities regulated by the cilium. Here we provide a recent account of the Cre/lox strategy. The generation and use of well-designed conditional alleles, as well as careful manipulation of embryonic stem cells are discussed. We also provide specific examples to illustrate the use of Cre/lox approaches to evaluate ciliary function in several tissues. With the recent characterization of multiple cilia proteomes along with efforts of several consortia to generate conditional alleles of all genes in the mouse, further use of conditional mutation approaches promise to yield many advances and surprises as we explore the functions of this increasingly complex organelle.
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Affiliation(s)
- Amber K O'Connor
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Boniface EJ, Lu J, Victoroff T, Zhu M, Chen W. FlEx-based transgenic reporter lines for visualization of Cre and Flp activity in live zebrafish. Genesis 2009; 47:484-91. [PMID: 19415631 DOI: 10.1002/dvg.20526] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Site-specific recombinases such as Cre and Flp are invaluable tools for genetic manipulations, but their usage in zebrafish has been limited. Incorporating recently developed flip-excision (FlEx) design that allows stable inversions, we have established zebrafish reporter lines that express bright and ubiquitous EGFP, but switch to express mCherry in the presence of Cre or Flp. Here, we demonstrate the stable inversion in the reporter lines, both in somatic cells and in the germ line by Cre or Flp, and the subsequent reinversion using the other recombinase. Using the reporter lines, we characterized cardiomyocyte-specific Cre lines and neuronal progenitor-specific and tamoxifen-dependent Cre lines. We also used the reporter lines for screening Cre- and Flp-based enhancer trap lines. Similar to the widely used Cre reporter lines in mice, these FlEx-based reporter lines will facilitate the use of recombinases for genetic manipulations in zebrafish.
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Affiliation(s)
- Emily J Boniface
- Vollum Institute, Oregon Health & Sciences University, Portland, USA
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Abstract
The Cre/lox site-specific recombination system has emerged as an important tool for the generation of conditional somatic mouse mutants. This method allows one to control gene activity in space and time in almost any tissue of the mouse, thus opening new avenues for studying gene function and for establishing sophisticated animal models of human diseases. A major technical advance in terms of in vivo inducibility was the development of ligand-dependent Cre recombinases that can be activated by administration of tamoxifen to the animal. Here we describe how tamoxifen-dependent Cre recombinases, so-called CreER recombinases, work and how they can be used to generate time- and tissue-specific mouse mutants. The focus will be on the CreER(T2) recombinase, which is currently the most successful CreER version. We will give an overview of available CreER(T2) transgenic mouse lines and present protocols that detail the generation of experimental mice for inducible gene knockout studies, the induction of recombination by tamoxifen treatment, and the analysis of the quality and quantity of recombination by reporter gene and target gene studies. Most of the protocols can also be used as general guidelines for the generation and characterization of Cre/lox-mediated genome modifications in mice.
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Hans S, Kaslin J, Freudenreich D, Brand M. Temporally-controlled site-specific recombination in zebrafish. PLoS One 2009; 4:e4640. [PMID: 19247481 PMCID: PMC2645673 DOI: 10.1371/journal.pone.0004640] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 01/29/2009] [Indexed: 01/26/2023] Open
Abstract
Conventional use of the site-specific recombinase Cre is a powerful technology in mouse, but almost absent in other vertebrate model organisms. In zebrafish, Cre-mediated recombination efficiency was previously very low. Here we show that using transposon-mediated transgenesis, Cre is in fact highly efficient in this organism. Furthermore, temporal control of recombination can be achieved by using the ligand-inducible CreERT2. Site-specific recombination only occurs upon administration of the drug tamoxifen (TAM) or its active metabolite, 4-hydroxy-tamoxifen (4-OHT). Cre-mediated recombination is detectable already 4 or 2 hours after administration of TAM or 4-OHT, demonstrating fast recombination kinetics. In addition, low doses of TAM allow mosaic labeling of single cells. Combined, our results show that conditional Cre/lox will be a valuable tool for both, embryonic and adult zebrafish studies. Furthermore, single copy insertion transgenesis of Cre/lox constructs suggest a strategy suitable also for other organisms.
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Affiliation(s)
- Stefan Hans
- Biotechnology Center and Center for Regenerative Therapies Dresden, Dresden University of Technology, Dresden, Germany
| | - Jan Kaslin
- Biotechnology Center and Center for Regenerative Therapies Dresden, Dresden University of Technology, Dresden, Germany
| | - Dorian Freudenreich
- Biotechnology Center and Center for Regenerative Therapies Dresden, Dresden University of Technology, Dresden, Germany
| | - Michael Brand
- Biotechnology Center and Center for Regenerative Therapies Dresden, Dresden University of Technology, Dresden, Germany
- * E-mail:
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Birling MC, Gofflot F, Warot X. Site-specific recombinases for manipulation of the mouse genome. Methods Mol Biol 2009; 561:245-63. [PMID: 19504076 DOI: 10.1007/978-1-60327-019-9_16] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Site-specific recombination systems are widespread and popular tools for all scientists interested in manipulating the mouse genome. In this chapter, we focus on the use of site-specific recombinases (SSR) to unravel the function of genes of the mouse. In the first part, we review the most commonly used SSR, Cre and Flp, as well as the newly developed systems such as Dre and PhiC31, and we present the inducible SSR systems. As experience has shown that these systems are not as straightforward as expected, particular attention is paid to facts and artefacts associated with their production and applications to study the mouse genome. In the next part of this chapter, we illustrate new applications of SSRs that allow engineering of the mouse genome with more and more precision, including the FLEX and the RMCE strategies. We conclude and suggest a workflow procedure that can be followed when using SSR to create your mouse model of interest. Together, these strategies and procedures provide the basis for a wide variety of studies that will ultimately lead to the analysis of the function of a gene at the cellular level in the mouse.
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Abstract
The endocannabinoid (ECB) system comprises cannabinoid receptors, ECBs and the whole machinery for the synthesis and degradation of ECBs. It has emerged as an important signalling system in the nervous system, controlling numerous physiological processes, including synaptic transmission, learning and memory, reward, feeding, neuroprotection, neuroinflammation, and neural development. This system is also implicated in various diseases of the nervous system, and thus has become a promising therapeutic target. The use of genetically modified mice has contributed crucially to our rapidly expanding knowledge of the ECB system. In this chapter, the existing mouse mutants targeting the ECB system will be discussed in detail. The use of conditional mutants has given an additional dimension to the analysis of the system, and, it is hoped, will finally enable us to understand this widespread and complex system in the context of intricate networks where different brain regions and neurotransmitter systems interact tightly with each other.
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Affiliation(s)
- Krisztina Monory
- Department of Physiological Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 6, D-55099, Mainz, Germany.
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A Cre-loxP-based mouse model for conditional somatic gene expression and knockdown in vivo by using avian retroviral vectors. Proc Natl Acad Sci U S A 2008; 105:10137-42. [PMID: 18621715 DOI: 10.1073/pnas.0800487105] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Site- and time-specific somatic gene transfer by using the avian sarcoma-leukosis retrovirus RCAS (replication-competent avian sarcoma-leukosis virus long terminal repeat with splice acceptor) has been shown to be a powerful tool to analyze gene function in vivo. RCAS retroviruses that express the avian subgroup A envelope transduce only mammalian cells genetically engineered to express the avian retroviral receptor, tumor virus A (TVA). Here, we generated a knockin mouse line termed LSL-R26(Tva-lacZ) with concomitant conditional expression of TVA and lacZ by targeting the Rosa26 locus. A loxP-flanked transcriptional stop cassette was used for conditional activation of TVA and LacZ expression in a Cre-recombinase-dependent manner. To demonstrate the ability of this system for conditional somatic gene transfer in vivo, we directed TVA expression to the pancreas. Introduction of an RCAS vector with Bryan-RSV polymerase and subgroup A envelope [RCASBP(A)] carrying oncogenic Kras(G12D) induced focal ductal pancreatic lesions that recapitulate human pancreatic intraepithelial neoplasias that progress to pancreatic ductal adenocarcinomas. TVA-mediated infection of genetically engineered mice with endogenous expression of Kras(G12D) in pancreatic progenitor cells by using RCASBP(A) virus carrying a short hairpin RNA directed against murine TP53, resulted in dramatically enhanced progression to invasive adenocarcinomas. These results show that conditional expression of TVA enables spatiotemporal gene expression and knockdown in a small subset of somatic cells in vivo. Therefore, it closely models carcinogenesis in humans where tumors evolve from somatic gene mutations in developmentally normal cells. Combined with the growing number of Cre expression models, RCAS-TVA-based gene expression and knockdown systems open up promising perspectives for analysis of gene function in a time-controlled and tissue-specific fashion in vitro and in vivo.
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(C)Re-combining textbook models of virus spread within the host. Cell Host Microbe 2008; 3:201-2. [PMID: 18407062 DOI: 10.1016/j.chom.2008.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Classic viral pathogenesis models postulate that tissues supporting efficient virus replication promote virus dissemination, which culminates in clinical illness. In this issue of Cell Host & Microbe, Sacher and colleagues use Cre/loxP recombination to label murine cytomegalovirus during replication in distinct cell types in vivo. Strikingly, they demonstrate that the most productive cell type in the host-the hepatocyte-contributes no progeny to dissemination to other tissues.
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Abstract
Stromal-epithelial interactions mediated by paracrine signaling mechanisms dictate prostate development and progression of prostate cancer. The regulatory role of androgens in both the prostate stromal and epithelial compartments set the prostate apart from many other organs and tissues with regard to gene targeting. The identification of androgen-dependent prostate epithelial promoters has allowed successful gene targeting to the prostate epithelial compartment. Currently, there are no transgenic mouse models available to specifically alter gene expression within the prostate stromal compartment. As a primary metastatic site for prostate cancer is bone, the functional dissection of the bone stromal compartment is important for understanding stromal-epithelial interactions associated with metastatic tumor growth. Use of currently available methodologies for the expression or deletion of gene expression in recent research studies has advanced our understanding of the stroma. However, the complexity of stromal heterogeneity within the prostate remains a challenge to obtaining compartment or cell-lineage-specific in vivo models necessary for furthering our understanding of prostatic developmental, benign, tumorigenic, and metastatic growth.
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Affiliation(s)
- Roger S Jackson
- Department of Urologic Surgery, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232-2765, USA
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Fechner H, Kurreck J. Vector-Mediated and Viral Delivery of Short Hairpin RNAs. THERAPEUTIC OLIGONUCLEOTIDES 2008. [DOI: 10.1039/9781847558275-00267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Henry Fechner
- Department of Cardiology and Pneumology, Charité-University Medicine Berlin, Campus Benjamin Franklin Hindenburgdamm 30 12200 Berlin Germany
| | - Jens Kurreck
- Institute for Chemistry and Biochemistry, Free University Berlin Thielallee 63 14195 Berlin Germany
- Institute of Industrial Genetics, University of Stuttgart Allmandring 31 70569 Stuttgart Germany
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Kohan DE. Progress in gene targeting: using mutant mice to study renal function and disease. Kidney Int 2008; 74:427-37. [PMID: 18418351 DOI: 10.1038/ki.2008.146] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Genetic engineering in mice has provided much information about gene function in renal health and disease. This knowledge has largely come from conventional transgenic approaches. Recently, methods have been developed to control the cell type, timing and reversibility of target gene expression. Advances in identifying promoters conferring renal cell-specific gene regulation in vivo have greatly facilitated interpretation of gene targeting studies. Site-specific recombinases have permitted cell-specific knockout of genes; Cre is the preeminent recombinase, but recent progress with other recombinases, include Flp and PhiC31, will likely increase the usefulness of this class of enzymes. Temporally regulated gene expression, particularly using doxycycline- and tamoxifen-inducible systems, holds great promise for avoiding developmental effects of gene mutations as well as facilitating comparison of the same animal's phenotype before and after gene modification. RNA interference is undergoing tremendous growth and has great potential for achieving gene knockdown quickly and reversibly. To date, however, the utility of these systems in modifying renal function in transgenic mice remains unproven. Finally, new gene targeting tools are in development that may substantially simplify generation of transgenic animals. This review discusses the state-of-the-art in gene targeting in the kidney, reviewing function, indications and limitations of the molecular biologic tools.
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Affiliation(s)
- Donald E Kohan
- Division of Nephrology, Department of Internal Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
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Abstract
Complementing mutant embryos or embryonic stem cells with normal cells in embryonic chimeras is a valuable tool for investigating phenotypes. Chimera approaches provide a method to examine the phenotype of mutant cells, including hematopoiesis, in mutants with early embryonic lethality. Complementation with normal cells in a chimera can, in most instances, rescue mutant cells to later stages of gestation and beyond, permitting analysis of contribution and function of mutant cells in various organs, both within the chimera, but also by using functional transplantation assays for hematopoietic stem and progenitor cells. This chapter describes principles and methods for the generation of mouse chimeras, for identification and quantitative analysis of cell contribution in chimeras, and for chimeric fetal liver transplantation into adult recipients and analysis of mutant cells in the adult.
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Affiliation(s)
- Sigrid Eckardt
- Center for Animal Transgenesis and Germ Cell Research,New Bolton Center, University of Pennsylvania, Kennett Square, PA, USA
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