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Balkawade RS, Chen C, Crowley MR, Crossman DK, Clapp WL, Verlander JW, Marshall CB. Podocyte-specific expression of Cre recombinase promotes glomerular basement membrane thickening. Am J Physiol Renal Physiol 2019; 316:F1026-F1040. [PMID: 30810063 DOI: 10.1152/ajprenal.00359.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Conditional gene targeting using Cre recombinase has offered a powerful tool to modify gene function precisely in defined cells/tissues and at specific times. However, in mammalian cells, Cre recombinase can be genotoxic. The importance of including Cre-expressing control mice to avoid misinterpretation and to maximize the validity of the experimental results has been increasingly recognized. While studying the role of podocytes in the pathogenesis of glomerular basement membrane (GBM) thickening, we used Cre recombinase driven by the podocyte-specific podocin promoter (NPHS2-Cre) to generate a conditional knockout. By conventional structural and functional measures (histology by periodic acid-Schiff staining, albuminuria, and plasma creatinine), we did not detect significant differences between NPHS2-Cre transgenic and wild-type control mice. However, surprisingly, the group that expressed Cre transgene alone developed signs of podocyte toxicity, including marked GBM thickening, loss of normal foot process morphology, and reduced Wilms tumor 1 expression. GBM thickening was characterized by altered expression of core structural protein laminin isoform α5β2γ1. RNA sequencing analysis of extracted glomeruli identified 230 genes that were significant and differentially expressed (applying a q < 0.05-fold change ≥ ±2 cutoff) in NPHS2-Cre mice compared with wild-type control mice. Many biological processes were reflected in the RNA sequencing data, including regulation of the extracellular matrix and pathways related to apoptosis and cell death. This study highlights the importance of including the appropriate controls for potential Cre-mediated toxicity in conditional gene-targeting experiments. Indeed, omitting the Cre transgene control can result in critical errors during interpretation of experimental data.
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Affiliation(s)
- Rohan S Balkawade
- Department of Veterans Affairs Medical Center , Birmingham, Alabama.,Division of Nephrology, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Chao Chen
- Division of Nephrology, Hypertension, and Renal Transplantation, College of Medicine Electron Microscopy Core, University of Florida , Gainesville, Florida
| | - Michael R Crowley
- Heflin Center for Genomic Science, Department of Genetics, University of Alabama at Birmingham , Birmingham, Alabama
| | - David K Crossman
- Heflin Center for Genomic Science, Department of Genetics, University of Alabama at Birmingham , Birmingham, Alabama
| | - William L Clapp
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida , Gainesville, Florida
| | - Jill W Verlander
- Division of Nephrology, Hypertension, and Renal Transplantation, College of Medicine Electron Microscopy Core, University of Florida , Gainesville, Florida
| | - Caroline B Marshall
- Department of Veterans Affairs Medical Center , Birmingham, Alabama.,Division of Nephrology, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama
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Panzica DA, Findlay AS, van Ladesteijn R, Collinson JM. The core planar cell polarity gene, Vangl2, maintains apical-basal organisation of the corneal epithelium. J Anat 2019; 234:106-119. [PMID: 28833131 PMCID: PMC6284432 DOI: 10.1111/joa.12676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2017] [Indexed: 12/23/2022] Open
Abstract
The role of the core planar cell polarity (PCP) pathway protein, Vangl2, was investigated in the corneal epithelium of the mammalian eye, a paradigm anatomical model of planar cell migration. The gene was conditionally knocked out in vivo and knocked down by siRNA, followed by immunohistochemical, behavioural and morphological analysis of corneal epithelial cells. The primary defects observed in vivo were of apical-basal organisation of the corneal epithelium, with abnormal stratification throughout life, mislocalisation of the cell membrane protein, Scribble, to the basal side of cells, and partial loss of the epithelial basement membrane. Planar defects in migration after wounding and in the presence of an applied electric field were noted. However, knockdown of Vangl2 also retarded cell migration in individual cells that had no contact with their neighbours, which precluded a classic PCP mechanism. It is concluded that some of the planar polarity phenotypes in PCP mutants may arise from disruption of apical-basal polarity.
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Affiliation(s)
- D. Alessio Panzica
- School of MedicineMedical Sciences and NutritionUniversity of AberdeenAberdeenUK
| | - Amy S. Findlay
- School of MedicineMedical Sciences and NutritionUniversity of AberdeenAberdeenUK
| | | | - J. Martin Collinson
- School of MedicineMedical Sciences and NutritionUniversity of AberdeenAberdeenUK
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Abstract
The fields of molecular genetics, biotechnology and synthetic biology are demanding ever more sophisticated molecular tools for programmed precise modification of cell genomic DNA and other DNA sequences. This review presents the current state of knowledge and development of one important group of DNA-modifying enzymes, the site-specific recombinases (SSRs). SSRs are Nature's 'molecular machines' for cut-and-paste editing of DNA molecules by inserting, deleting or inverting precisely defined DNA segments. We survey the SSRs that have been put to use, and the types of applications for which they are suitable. We also discuss problems associated with uses of SSRs, how these problems can be minimized, and how recombinases are being re-engineered for improved performance and novel applications.
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Stiedl P, Grabner B, Zboray K, Bogner E, Casanova E. Modeling cancer using genetically engineered mice. Methods Mol Biol 2015; 1267:3-18. [PMID: 25636462 DOI: 10.1007/978-1-4939-2297-0_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Genetically engineered mouse (GEM) models have proven to be a powerful tool to study tumorigenesis. The mouse is the preferred complex organism used in cancer studies due to the high number and versatility of genetic tools available for this species. GEM models can mimic point mutations, gene amplifications, short and large deletions, translocations, etc.; thus, most of the genetic aberrations found in human tumors can be modeled in GEM, making GEM models a very attractive system. Furthermore, recent developments in mouse genetics may facilitate the generation of GEM models with increased mutational complexity, therefore resembling human tumors better. Within this review, we will discuss the different possibilities of modeling tumorigenesis using GEM and the future developments within the field.
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Affiliation(s)
- Patricia Stiedl
- Ludwig Boltzmann Institute for Cancer Research (LBI-CR), Währinger Str. 13a, Vienna, 1090, Austria
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Gangoda L, Doerflinger M, Lee YY, Rahimi A, Etemadi N, Chau D, Milla L, O'Connor L, Puthalakath H. Cre transgene results in global attenuation of the cAMP/PKA pathway. Cell Death Dis 2012; 3:e365. [PMID: 22875002 PMCID: PMC3434654 DOI: 10.1038/cddis.2012.110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Use of the cre transgene in in vivo mouse models to delete a specific 'floxed' allele is a well-accepted method for studying the effects of spatially or temporarily regulated genes. During the course of our investigation into the effect of cyclic adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) expression on cell death, we found that cre expression either in cultured cell lines or in transgenic mice results in global changes in PKA target phosphorylation. This consequently alters gene expression profile and changes in cytokine secretion such as IL-6. These effects are dependent on its recombinase activity and can be attributed to the upregulation of specific inhibitors of PKA (PKI). These results may explain the cytotoxicity often associated with cre expression in many transgenic animals and may also explain many of the phenotypes observed in the context of Cre-mediated gene deletion. Our results may therefore influence the interpretation of data generated using the conventional cre transgenic system.
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Affiliation(s)
- L Gangoda
- Department of Biochemistry, La Trobe Institute of Molecular Science, La Trobe University, Kingsbury Drive, Bundoora, Victoria, Australia 3086
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A novel Ncr1-Cre mouse reveals the essential role of STAT5 for NK-cell survival and development. Blood 2010; 117:1565-73. [PMID: 21127177 DOI: 10.1182/blood-2010-06-291633] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We generated a transgenic mouse line that expresses the Cre recombinase under the control of the Ncr1 (p46) promoter. Cre-mediated recombination was tightly restricted to natural killer (NK) cells, as revealed by crossing Ncr1-iCreTg mice to the eGFP-LSLTg reporter strain. Ncr1-iCreTg mice were further used to study NK cell-specific functions of Stat5 (signal transducers and activators of transcription 5) by generating Stat5(f/f) Ncr1-iCreTg animals. Stat5(f/f) Ncr1-iCreTg mice were largely devoid of NK cells in peripheral lymphoid organs. In the bone marrow, NK-cell maturation was abrogated at the NK cell-precursor stage. Moreover, we found that in vitro deletion of Stat5 in interleukin 2-expanded NK cells was incompatible with NK-cell viability. In vivo assays confirmed the complete abrogation of NK cell-mediated tumor control against B16F10-melanoma cells. In contrast, T cell-mediated tumor surveillance against MC38-adenocarcinoma cells was undisturbed. In summary, the results of our study show that STAT5 has a cell-intrinsic role in NK-cell development and that Ncr1-iCreTg mice are a powerful novel tool with which to study NK-cell development, biology, and function.
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Mirones I, Conti CJ, Martínez J, Garcia M, Larcher F. Complexity of VEGF Responses in Skin Carcinogenesis Revealed through Ex Vivo Assays Based on a VEGF-A Null Mouse Keratinocyte Cell Line. J Invest Dermatol 2009; 129:730-41. [DOI: 10.1038/jid.2008.292] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Hameyer D, Loonstra A, Eshkind L, Schmitt S, Antunes C, Groen A, Bindels E, Jonkers J, Krimpenfort P, Meuwissen R, Rijswijk L, Bex A, Berns A, Bockamp E. Toxicity of ligand-dependent Cre recombinases and generation of a conditional Cre deleter mouse allowing mosaic recombination in peripheral tissues. Physiol Genomics 2007; 31:32-41. [PMID: 17456738 DOI: 10.1152/physiolgenomics.00019.2007] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Ligand-activated Cre recombinases are widely used for studying gene function in vitro and in conditional mouse models. To compare ligand-dependent Cre recombinases, different Cre estrogen receptor fusions were introduced into the ROSA26 locus of embryonic stem (ES) cells and assayed for genotoxicity and recombination efficiency. Of the tested recombinases, the CreERT2 variant showed no toxicity and was highly responsive to ligand induction. To constitutively express CreERT2 in mice and also to clarify whether the CreERT2 system displays background activity, we generated a knock-in mouse line harboring the CreERT2 coding region under the control of the ROSA26 locus. Analysis of this ROSA26-CreERT2 deleter mouse with different reporter strains revealed ubiquitous recombination in the embryo and partial recombination in peripheral and hematopoietic tissues but no effective CreERT2 expression in the brain. Furthermore, using flow cytometry, we found low-level background recombination in noninduced bitransgenic ROSA26-CreERT2/EGFP reporter mice. To determine whether background activity poses a general problem for conducting conditional in vivo experiments with the ROSA26-CreERT2 deleter, we used a sensitive conditional skin cancer model. In this assay, cancer induction was completely restricted to induced bitransgenic CreERT2/K-Ras(V12) mice, whereas noninduced control animals did not show any sign of cancer, indicating the usefulness of the ROSA-CreERT2 system for regulating conditional gene expression in vivo. The ROSA26-CreERT2 deleter strain will be a convenient experimental tool for studying gene function under circumstances requiring partial induction of recombination in peripheral tissues and will be useful for uncovering previously unknown or unsuspected phenotypes.
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Affiliation(s)
- Dorothe Hameyer
- Institute of Toxicology/Mouse Genetics, Johannes Gutenberg-Universität Mainz, Mainz, Germany
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Akopian A, Marshall Stark W. Site‐Specific DNA Recombinases as Instruments for Genomic Surgery. ADVANCES IN GENETICS 2005; 55:1-23. [PMID: 16291210 DOI: 10.1016/s0065-2660(05)55001-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Site-specific DNA recombinases can "cut and paste" DNA. For example, they can promote excision of specific DNA segments or insertion of new DNA segments in specific places. However, natural recombinases act only at their cognate recombination sites, so current applications are limited to genetically modified organisms in which these sites have been introduced into the genome. Transposases also catalyze DNA rearrangements; they promote insertion of specific DNA sequences but at nonspecific locations. Applicability of site-specific recombinases and transposases in experimental genetics, biotechnology, and gene therapy would be much wider if they could be re-engineered so as to act specifically at chosen sequences within an organism's natural genome. This review will discuss progress towards the creation of such "designer" recombinases.
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Affiliation(s)
- Aram Akopian
- Institute of Biomedical & Life Sciences University of Glasgow, Glasgow G11 6NU, Scotland, UK
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Abstract
In the postgenomic era the mouse will be central to the challenge of ascribing a function to the 40,000 or so genes that constitute our genome. In this review, we summarize some of the classic and modern approaches that have fueled the recent dramatic explosion in mouse genetics. Together with the sequencing of the mouse genome, these tools will have a profound effect on our ability to generate new and more accurate mouse models and thus provide a powerful insight into the function of human genes during the processes of both normal development and disease.
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