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Islam F, Lewis MR, Craig JD, Leyendecker PM, Deans TL. Advancing in vivo reprogramming with synthetic biology. Curr Opin Biotechnol 2024; 87:103109. [PMID: 38520824 PMCID: PMC11162311 DOI: 10.1016/j.copbio.2024.103109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/23/2024] [Accepted: 02/27/2024] [Indexed: 03/25/2024]
Abstract
Reprogramming cells will play a fundamental role in shaping the future of cell therapies by developing new strategies to engineer cells for improved performance and higher-order physiological functions. Approaches in synthetic biology harness cells' natural ability to sense diverse signals, integrate environmental inputs to make decisions, and execute complex behaviors based on the health of the organism or tissue. In this review, we highlight strategies in synthetic biology to reprogram cells, and discuss how recent approaches in the delivery of modified mRNA have created new opportunities to alter cell function in vivo. Finally, we discuss how combining concepts from synthetic biology and the delivery of mRNA in vivo could provide a platform for innovation to advance in vivo cellular reprogramming.
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Affiliation(s)
- Farhana Islam
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Mitchell R Lewis
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - James D Craig
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Peyton M Leyendecker
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Tara L Deans
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
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2
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Cabrera A, Edelstein HI, Glykofrydis F, Love KS, Palacios S, Tycko J, Zhang M, Lensch S, Shields CE, Livingston M, Weiss R, Zhao H, Haynes KA, Morsut L, Chen YY, Khalil AS, Wong WW, Collins JJ, Rosser SJ, Polizzi K, Elowitz MB, Fussenegger M, Hilton IB, Leonard JN, Bintu L, Galloway KE, Deans TL. The sound of silence: Transgene silencing in mammalian cell engineering. Cell Syst 2022; 13:950-973. [PMID: 36549273 PMCID: PMC9880859 DOI: 10.1016/j.cels.2022.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/22/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022]
Abstract
To elucidate principles operating in native biological systems and to develop novel biotechnologies, synthetic biology aims to build and integrate synthetic gene circuits within native transcriptional networks. The utility of synthetic gene circuits for cell engineering relies on the ability to control the expression of all constituent transgene components. Transgene silencing, defined as the loss of expression over time, persists as an obstacle for engineering primary cells and stem cells with transgenic cargos. In this review, we highlight the challenge that transgene silencing poses to the robust engineering of mammalian cells, outline potential molecular mechanisms of silencing, and present approaches for preventing transgene silencing. We conclude with a perspective identifying future research directions for improving the performance of synthetic gene circuits.
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Affiliation(s)
- Alan Cabrera
- Department of Bioengineering, Rice University, Houston, TX 77005, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hailey I Edelstein
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA; The Eli and Edythe Broad CIRM Center, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Fokion Glykofrydis
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA
| | - Kasey S Love
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sebastian Palacios
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Josh Tycko
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Meng Zhang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, Urbana, IL 61801, USA
| | - Sarah Lensch
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Cara E Shields
- Wallace H. Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA
| | - Mark Livingston
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Ron Weiss
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, Urbana, IL 61801, USA
| | - Karmella A Haynes
- Wallace H. Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA
| | - Leonardo Morsut
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA
| | - Yvonne Y Chen
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA; Parker Institute for Cancer Immunotherapy Center at UCLA, Los Angeles, CA 90095, USA
| | - Ahmad S Khalil
- Biological Design Center and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Wilson W Wong
- Biological Design Center and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - James J Collins
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA; Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Susan J Rosser
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Karen Polizzi
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK; Imperial College Centre for Synthetic Biology, South Kensington Campus, London, UK
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland; Faculty of Science, University of Basel, Mattenstrasse 26, Basel 4058, Switzerland
| | - Isaac B Hilton
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Joshua N Leonard
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA; The Eli and Edythe Broad CIRM Center, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Lacramioara Bintu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kate E Galloway
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tara L Deans
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
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Cho JD, Yang M, Santa-Maria I. Modeling Alzheimer's disease: considerations for a better translational and replicable mouse model. Neural Regen Res 2022; 17:2448-2449. [PMID: 35535894 PMCID: PMC9120700 DOI: 10.4103/1673-5374.335787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/01/2021] [Accepted: 09/08/2021] [Indexed: 12/01/2022] Open
Affiliation(s)
- Joshua D. Cho
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Mu Yang
- The Mouse NeuroBehavior Core. Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Ismael Santa-Maria
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
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Efficient targeted transgenesis of large donor DNA into multiple mouse genetic backgrounds using bacteriophage Bxb1 integrase. Sci Rep 2022; 12:5424. [PMID: 35361849 PMCID: PMC8971409 DOI: 10.1038/s41598-022-09445-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/23/2022] [Indexed: 12/12/2022] Open
Abstract
The development of mouse models of human disease and synthetic biology research by targeted transgenesis of large DNA constructs represent a significant genetic engineering hurdle. We developed an efficient, precise, single-copy integration of large transgenes directly into zygotes using multiple mouse genetic backgrounds. We used in vivo Bxb1 mediated recombinase-mediated cassette exchange (RMCE) with a transgene “landing pad” composed of dual heterologous Bxb1 attachment (att) sites in cis, within the Gt(ROSA)26Sor safe harbor locus. RMCE of donor was achieved by microinjection of vector DNA carrying cognate attachment sites flanking the donor transgene with Bxb1-integrase mRNA. This approach achieves perfect vector-free integration of donor constructs at efficiencies > 40% with up to ~ 43 kb transgenes. Coupled with a nanopore-based Cas9-targeted sequencing (nCATS), complete verification of precise insertion sequence was achieved. As a proof-of-concept we describe the development of C57BL/6J and NSG Krt18-ACE2 models for SARS-CoV2 research with verified heterozygous N1 animals within ~ 4 months. Additionally, we created a series of mice with diverse backgrounds carrying a single att site including FVB/NJ, PWK/PhJ, NOD/ShiLtJ, CAST/EiJ and DBA/2J allowing for rapid transgene insertion. Combined, this system enables predictable, rapid development with simplified characterization of precisely targeted transgenic animals across multiple genetic backgrounds.
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Rauschendorfer T, Gurri S, Heggli I, Maddaluno L, Meyer M, Inglés-Prieto Á, Janovjak H, Werner S. Acute and chronic effects of a light-activated FGF receptor in keratinocytes in vitro and in mice. Life Sci Alliance 2021; 4:4/11/e202101100. [PMID: 34548382 PMCID: PMC8473723 DOI: 10.26508/lsa.202101100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/24/2022] Open
Abstract
Optogenetic activation of FGFR2 allowed temporally precise induction of signaling and behavioural changes, but counter-regulation at multiple levels prevented a sustained response in keratinocytes. FGFs and their high-affinity receptors (FGFRs) play key roles in development, tissue repair, and disease. Because FGFRs bind overlapping sets of ligands, their individual functions cannot be determined using ligand stimulation. Here, we generated a light-activated FGFR2 variant (OptoR2) to selectively activate signaling by the major FGFR in keratinocytes. Illumination of OptoR2-expressing HEK 293T cells activated FGFR signaling with remarkable temporal precision and promoted cell migration and proliferation. In murine and human keratinocytes, OptoR2 activation rapidly induced the classical FGFR signaling pathways and expression of FGF target genes. Surprisingly, multi-level counter-regulation occurred in keratinocytes in vitro and in transgenic mice in vivo, including OptoR2 down-regulation and loss of responsiveness to light activation. These results demonstrate unexpected cell type–specific limitations of optogenetic FGFRs in long-term in vitro and in vivo settings and highlight the complex consequences of transferring optogenetic cell signaling tools into their relevant cellular contexts.
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Affiliation(s)
- Theresa Rauschendorfer
- Department of Biology, Institute of Molecular Health Sciences, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Selina Gurri
- Department of Biology, Institute of Molecular Health Sciences, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Irina Heggli
- Department of Biology, Institute of Molecular Health Sciences, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Luigi Maddaluno
- Department of Biology, Institute of Molecular Health Sciences, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | - Michael Meyer
- Department of Biology, Institute of Molecular Health Sciences, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
| | | | - Harald Janovjak
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria .,Australian Regenerative Medicine Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Australia.,European Molecular Biology Laboratory Australia, Monash University, Clayton, Australia
| | - Sabine Werner
- Department of Biology, Institute of Molecular Health Sciences, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
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Lindner L, Cayrou P, Rosahl TW, Zhou HH, Birling MC, Herault Y, Pavlovic G. Droplet digital PCR or quantitative PCR for in-depth genomic and functional validation of genetically altered rodents. Methods 2021; 191:107-119. [PMID: 33838271 DOI: 10.1016/j.ymeth.2021.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/24/2021] [Accepted: 04/01/2021] [Indexed: 12/12/2022] Open
Abstract
Gene targeting and additive (random) transgenesis have proven to be powerful technologies with which to decipher the mammalian genome. With the advent of CRISPR/Cas9 genome editing, the ability to inactivate or modify the function of a gene has become even more accessible. However, the impact of each generated modification may be different from what was initially desired. Minimal validation of mutant alleles from genetically altered (GA) rodents remains essential to guarantee the interpretation of experimental results. The protocol described here combines design strategies for genomic and functional validation of genetically modified alleles with droplet digital PCR (ddPCR) or quantitative PCR (qPCR) for target DNA or mRNA quantification. In-depth analysis of the results obtained with GA models through the analysis of target DNA and mRNA quantification is also provided, to evaluate which pitfalls can be detected using these two methods, and we propose recommendations for the characterization of different type of mutant allele (knock-out, knock-in, conditional knock-out, FLEx, IKMC model or transgenic). Our results also highlight the possibility that mRNA expression of any mutated allele can be different from what might be expected in theory or according to common assumptions. For example, mRNA analyses on knock-out lines showed that nonsense-mediated mRNA decay is generally not achieved with a critical-exon approach. Likewise, comparison of multiple conditional lines crossed with the same CreERT2 deleter showed that the inactivation outcome was very different for each conditional model. DNA quantification by ddPCR of G0 to G2 generations of transgenic rodents generated by pronuclear injection showed an unexpected variability, demonstrating that G1 generation rodents cannot be considered as established lines.
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Affiliation(s)
- Loic Lindner
- PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France
| | - Pauline Cayrou
- PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France
| | - Thomas W Rosahl
- Merck & Co., Inc., 2000 Galloping Hill Rd, Kenilworth, NJ 07033, USA
| | - Heather H Zhou
- Merck & Co., Inc., 2000 Galloping Hill Rd, Kenilworth, NJ 07033, USA
| | - Marie-Christine Birling
- PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France
| | - Yann Herault
- PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France
| | - Guillaume Pavlovic
- PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France.
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Sontayananon N, Redwood C, Davies B, Gehmlich K. Fluorescent PSC-Derived Cardiomyocyte Reporter Lines: Generation Approaches and Their Applications in Cardiovascular Medicine. BIOLOGY 2020; 9:biology9110402. [PMID: 33207727 PMCID: PMC7697758 DOI: 10.3390/biology9110402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
Recent advances have made pluripotent stem cell (PSC)-derived cardiomyocytes an attractive option to model both normal and diseased cardiac function at the single-cell level. However, in vitro differentiation yields heterogeneous populations of cardiomyocytes and other cell types, potentially confounding phenotypic analyses. Fluorescent PSC-derived cardiomyocyte reporter systems allow specific cell lineages to be labelled, facilitating cell isolation for downstream applications including drug testing, disease modelling and cardiac regeneration. In this review, the different genetic strategies used to generate such reporter lines are presented with an emphasis on their relative technical advantages and disadvantages. Next, we explore how the fluorescent reporter lines have provided insights into cardiac development and cardiomyocyte physiology. Finally, we discuss how exciting new approaches using PSC-derived cardiomyocyte reporter lines are contributing to progress in cardiac cell therapy with respect to both graft adaptation and clinical safety.
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Affiliation(s)
- Naeramit Sontayananon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK; (N.S.); (C.R.)
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK; (N.S.); (C.R.)
| | - Benjamin Davies
- Wellcome Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
- Correspondence: (B.D.); (K.G.)
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK; (N.S.); (C.R.)
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
- Correspondence: (B.D.); (K.G.)
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Kropp PA, Rushing GV, Brockman AA, Yu ENZ, Ihrie RA, Gannon M. Unexpected effects of ivermectin and selamectin on inducible Cre ER activity in mice. Lab Anim Res 2020; 36:36. [PMID: 33042783 PMCID: PMC7542348 DOI: 10.1186/s42826-020-00069-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/28/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anti-parasitics are frequently used in research animal facilities to treat a multitude of common infections, with pinworms and fur mites being amongst the most common. Ivermectin and selamectin are common oral and topical treatments for these infections, respectively. Although commonly thought to be innocuous to both the research animals and any transgenic elements that the animals may carry, evidence exists that ivermectin is capable of activating the recombinase activity of at least one CreER. The goal of the current study was to determine if there was an effect of either anti-parasitic agent on the activity of CreER proteins in transgenic mice. CASE PRESENTATION We analyzed the offspring of transgenic mice exposed to either ivermectin or selamectin during pregnancy and nursing. Through analysis of reporter genes co-expressed with multiple, independently generated transgenic CreER drivers, we report here that ivermectin and selamectin both alter recombinase activity and thus may have unintended consequences on gene inactivation studies in mice. CONCLUSIONS Although the mechanisms by which ivermectin and selamectin affect CreER activity in the offspring of treated dams remain unclear, the implications are important nonetheless. Treatment of pregnant transgenic mice with these anti-parasitics has the potential to alter transgene activity in the offspring. Special considerations should be made when planning treatment of transgenic mice with either of these pharmacologics.
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Affiliation(s)
- Peter A. Kropp
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN USA
- Present Address: Laboratory of Biochemistry and Genetics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20886 USA
| | | | - Asa A. Brockman
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN USA
| | - Erin N. Z. Yu
- Department of Pathology, Immunology and Microbiology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Rebecca A. Ihrie
- Neuroscience Program, Vanderbilt University, Nashville, TN USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN USA
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN USA
| | - Maureen Gannon
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN USA
- Department of Veteran’s Affairs, Tennessee Valley Health Authority, Nashville, TN USA
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Transgenic overexpression of glutathione S-transferase μ-type 1 reduces hypertension and oxidative stress in the stroke-prone spontaneously hypertensive rat. J Hypertens 2020; 37:985-996. [PMID: 30308595 DOI: 10.1097/hjh.0000000000001960] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Combined congenic breeding and microarray gene expression profiling previously identified glutathione S-transferase μ-type 1 (Gstm1) as a positional and functional candidate gene for blood pressure (BP) regulation in the stroke-prone spontaneously hypertensive (SHRSP) rat. Renal Gstm1 expression in SHRSP rats is significantly reduced when compared with normotensive Wistar Kyoto (WKY) rats. As Gstm1 plays an important role in the secondary defence against oxidative stress, significantly lower expression levels may be functionally relevant in the development of hypertension. The aim of this study was to investigate the role of Gstm1 in BP regulation and oxidative stress by transgenic overexpression of the Gstm1 gene. METHOD Two independent Gstm1 transgenic SHRSP lines were generated by microinjecting SHRSP embryos with a linear construct controlled by the EF-1α promoter encoding WKY Gstm1 cDNA [SHRSP-Tg(Gstm1)1 and SHRSP-Tg(Gstm1)2]. RESULTS Transgenic rats exhibit significantly reduced BP and pulse pressure when compared with SHRSP [systolic: SHRSP 205.2 ± 3.7 mmHg vs. SHRSP-Tg(Gstm1)1 175.5 ± 1.6 mmHg and SHRSP-Tg(Gstm1)2 172 ± 3.2 mmHg, P < 0.001; pulse pressure: SHRSP 58.4 ± 0.73 mmHg vs. SHRSP-Tg(Gstm1)1 52.7 ± 0.19 mmHg and SHRSP-Tg(Gstm1)2 40.7 ± 0.53 mmHg, P < 0.001]. Total renal and aortic Gstm1 expression in transgenic animals was significantly increased compared with SHRSP [renal relative quantification (RQ): SHRSP-Tg(Gstm1)1 1.95 vs. SHRSP 1.0, P < 0.01; aorta RQ: SHRSP-Tg(Gstm1)1 2.8 vs. SHRSP 1.0, P < 0.05]. Renal lipid peroxidation (malondialdehyde: protein) and oxidized : reduced glutathione ratio levels were significantly reduced in both transgenic lines when compared with SHRSP [malondialdehyde: SHRSP 0.04 ± 0.009 μmol/l vs. SHRSP-Tg(Gstm1)1 0.024 ± 0.002 μmol/l and SHRSP-Tg(Gstm1)2 0.021 ± 0.002 μmol/l; (oxidized : reduced glutathione ratio): SHRSP 5.19 ± 2.26 μmol/l vs. SHRSP-Tg(Gstm1)1 0.17 ± 0.11 μmol/l and SHRSP-Tg(Gstm1)2 0.47 ± 0.22 μmol/l]. Transgenic SHRSP rats containing the WKY Gstm1 gene demonstrate significantly lower BP, reduced oxidative stress and improved levels of renal Gstm1 expression. CONCLUSION These data support the hypothesis that reduced renal Gstm1 plays a role in the development of hypertension.
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Eun K, Hong N, Jeong YW, Park MG, Hwang SU, Jeong YIK, Choi EJ, Olsson PO, Hwang WS, Hyun SH, Kim H. Transcriptional activities of human elongation factor-1α and cytomegalovirus promoter in transgenic dogs generated by somatic cell nuclear transfer. PLoS One 2020; 15:e0233784. [PMID: 32492024 PMCID: PMC7269240 DOI: 10.1371/journal.pone.0233784] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 05/12/2020] [Indexed: 11/30/2022] Open
Abstract
Recent advances in somatic cell nuclear transfer (SCNT) in canines facilitate the production of canine transgenic models. Owing to the importance of stable and strong promoter activity in transgenic animals, we tested human elongation factor 1α (hEF1α) and cytomegalovirus (CMV) promoter sequences in SCNT transgenic dogs. After transfection, transgenic donor fibroblasts with the hEF1α-enhanced green fluorescence protein (EGFP) transgene were successfully isolated using fluorescence-activated cell sorting (FACS). We obtained four puppies, after SCNT, and identified three puppies as being transgenic using PCR analysis. Unexpectedly, EGFP regulated by hEF1α promoter was not observed at the organismal and cellular levels in these transgenic dogs. EGFP expression was rescued by the inhibition of DNA methyltransferases, implying that the hEF1α promoter is silenced by DNA methylation. Next, donor cells with CMV-EGFP transgene were successfully established and SCNT was performed. Three puppies of six born puppies were confirmed to be transgenic. Unlike hEF1α-regulated EGFP, CMV-regulated EGFP was strongly detectable at both the organismal and cellular levels in all transgenic dogs, even after 19 months. In conclusion, our study suggests that the CMV promoter is more suitable, than the hEF1α promoter, for stable transgene expression in SCNT-derived transgenic canine model.
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Affiliation(s)
- Kiyoung Eun
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
- Institute of Animal Molecular Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
| | - Nayoung Hong
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
- Institute of Animal Molecular Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
| | - Yeon Woo Jeong
- Sooam Biotech Research Foundation, Guro-gu, Seoul, Republic of Korea
| | - Min Gi Park
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
- Institute of Animal Molecular Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
| | - Seon-Ung Hwang
- Laboratory of Veterinary Embryology and Biotechnology, College of Veterinary Medicine, Chungbuk National University, Seowon-gu, Cheongju, Republic of Korea
- Institute of Stem Cell & Regenerative Medicine, Chungbuk National University, Seowon-gu, Cheongju, Republic of Korea
| | - Yeon I. K. Jeong
- Sooam Biotech Research Foundation, Guro-gu, Seoul, Republic of Korea
| | - Eun Ji Choi
- Sooam Biotech Research Foundation, Guro-gu, Seoul, Republic of Korea
| | - P. Olof Olsson
- Sooam Biotech Research Foundation, Guro-gu, Seoul, Republic of Korea
| | - Woo Suk Hwang
- Sooam Biotech Research Foundation, Guro-gu, Seoul, Republic of Korea
| | - Sang-Hwan Hyun
- Laboratory of Veterinary Embryology and Biotechnology, College of Veterinary Medicine, Chungbuk National University, Seowon-gu, Cheongju, Republic of Korea
- Institute of Stem Cell & Regenerative Medicine, Chungbuk National University, Seowon-gu, Cheongju, Republic of Korea
- * E-mail: (SHH); (HK)
| | - Hyunggee Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
- Institute of Animal Molecular Biotechnology, Korea University, Seongbuk-gu, Seoul, Republic of Korea
- * E-mail: (SHH); (HK)
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Cunningham AM, Santos TL, Gutzeit VA, Hamilton H, Hen R, Donaldson ZR. Functional Interrogation of a Depression-Related Serotonergic Single Nucleotide Polymorphism, rs6295, Using a Humanized Mouse Model. ACS Chem Neurosci 2019; 10:3197-3206. [PMID: 30694044 DOI: 10.1021/acschemneuro.8b00638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The serotonin 1A receptor (5-HT1A) system has been extensively implicated in modulating mood and behavior. Notably, 5-HT1A levels in humans display remarkable variation, and differences in receptor levels have been linked with a variety of psychiatric disorders. Further, reduction of receptor levels by 30-50% in mice suggests that changes in receptor levels that model existing human variation are sufficient to drive behavioral alterations. As a result, genetic mechanisms that modulate human 5-HT1A levels may be important for explaining individual differences in mood and behavior, representing a potential source of psychiatric disease risk. One common genetic variant implicated in differential 5-HT1A levels is the G/C single nucleotide polymorphism (SNP) rs6295, located upstream of the human 5-HT1A gene. This SNP differentially binds the transcription factor, NUDR/Deaf1, leading to cell-type specific effects on transcription in vitro. To investigate the direct effects of this SNP in the heterogeneous cellular context of the brain, we generated humanized transgenic mice using a design that maximized the local transcriptional landscape of the human HTR1A gene while also controlling for effects of genomic insertion location. We integrated a 180 kb human bacteria artificial chromosome (BAC) transgene containing G- and C-alleles of rs6295 flanked by FRT or loxP sites. Subsequent deletion of each allele by Cre- or Flp-recombinase resulted in rs6295G and C alleles in the same genomic location. These alleles were bred onto a 5-HT1A null mouse such that the human BAC was the sole source of 5-HT1A in these mice. We generated three separate lines, two of which had detectable human 5-HT1A levels in the brain, although none displayed expression in the raphe. Of these, one line exhibited rs6295-dependent differences in 5-HT1A levels and differences in behavior, even though the overall levels were considerably lower than native expression levels. The line-dependent effect of rs6295 on protein levels and behavior may depend upon differences in background genetic factors or different insertion sites across each line. This work confirms that relatively subtle differences in 5-HT1A levels can contribute to differences in behavior and highlights the challenges of modeling human noncoding genetic variation in mice.
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Affiliation(s)
- Ashley M. Cunningham
- Division of Integrative Neuroscience, New York State Psychiatric Institute and Columbia University, New York, New York 10032, United States
- Departments of Molecular, Cellular, and Developmental Biology and Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Tabia L. Santos
- Division of Integrative Neuroscience, New York State Psychiatric Institute and Columbia University, New York, New York 10032, United States
| | - Vanessa A. Gutzeit
- Division of Integrative Neuroscience, New York State Psychiatric Institute and Columbia University, New York, New York 10032, United States
| | - Heather Hamilton
- Departments of Molecular, Cellular, and Developmental Biology and Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - René Hen
- Division of Integrative Neuroscience, New York State Psychiatric Institute and Columbia University, New York, New York 10032, United States
| | - Zoe R. Donaldson
- Departments of Molecular, Cellular, and Developmental Biology and Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado 80309, United States
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12
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Norum JH, Frings O, Kasper M, Bergholtz H, Zell Thime H, Bergström Å, Andersson A, Kuiper R, Fredlund E, Sørlie T, Toftgård R. GLI1‐induced mammary gland tumours are transplantable and maintain major molecular features. Int J Cancer 2019; 146:1125-1138. [DOI: 10.1002/ijc.32522] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/24/2019] [Accepted: 06/12/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Jens Henrik Norum
- Department of Biosciences and NutritionKarolinska Institutet Huddinge Sweden
- Department of Cancer GeneticsInstitute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital Oslo Norway
| | - Oliver Frings
- Science for Life Laboratory, Department of Oncology‐PathologyKarolinska Institutet Stockholm Sweden
| | - Maria Kasper
- Department of Biosciences and NutritionKarolinska Institutet Huddinge Sweden
| | - Helga Bergholtz
- Department of Cancer GeneticsInstitute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital Oslo Norway
| | - Helene Zell Thime
- Department of Cancer GeneticsInstitute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital Oslo Norway
| | - Åsa Bergström
- Department of Biosciences and NutritionKarolinska Institutet Huddinge Sweden
| | - Agneta Andersson
- Department of Biosciences and NutritionKarolinska Institutet Huddinge Sweden
| | - Raoul Kuiper
- Department of Laboratory Medicine and Center for Innovative Medicine (CIMED)Karolinska Institutet Huddinge Sweden
| | - Erik Fredlund
- Science for Life Laboratory, Department of Oncology‐PathologyKarolinska Institutet Stockholm Sweden
| | - Therese Sørlie
- Department of Cancer GeneticsInstitute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital Oslo Norway
| | - Rune Toftgård
- Department of Biosciences and NutritionKarolinska Institutet Huddinge Sweden
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13
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Bonifer C, Cockerill PN. Chromatin priming of genes in development: Concepts, mechanisms and consequences. Exp Hematol 2017; 49:1-8. [PMID: 28185904 DOI: 10.1016/j.exphem.2017.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/19/2017] [Accepted: 01/21/2017] [Indexed: 01/06/2023]
Abstract
During ontogeny, cells progress through multiple alternate differentiation states by activating distinct gene regulatory networks. In this review, we highlight the important role of chromatin priming in facilitating gene activation during lineage specification and in maintaining an epigenetic memory of previous gene activation. We show that chromatin priming is part of a hugely diverse repertoire of regulatory mechanisms that genes use to ensure that they are expressed at the correct time, in the correct cell type, and at the correct level, but also that they react to signals. We also emphasize how increasing our knowledge of these principles could inform our understanding of developmental failure and disease.
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Affiliation(s)
- Constanze Bonifer
- Institute of Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, Birmingham, UK.
| | - Peter N Cockerill
- Institute of Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, Birmingham, UK.
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14
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Du GM, Wu JG, Luo BP, Hu ZH, Li LA, Liu MJ. RNAi-mediated Ghrelin affects gastric H(+)-K(+)-ATPase activity and expression of GOAT-Ghrelin system in vitro. Gen Comp Endocrinol 2016; 228:48-52. [PMID: 26873629 DOI: 10.1016/j.ygcen.2016.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 10/22/2022]
Abstract
Ghrelin has been implicated in the regulation of gastric functional development, and its physiological functions are mediated by Ghrelin-O-acyltransferase (GOAT) which is capable of generating the active form of this polypeptide hormone. However, whether and how ghrelin gene silencing may modify gastric acid secretion and GOAT-Ghrelin system is yet to be explored. The study was performed in gastric mucosal cells from weanling piglets in vitro. We evaluated the effect of ghrelin on gastric acid secretion, gene expression of GOAT and ghrelin as well as ghrelin levels by RNA interference assay. shGhrelin triggered the down-regulation of ghrelin mRNA expression (P<0.05) via an RNAi mechanism, as observed by real-time RT-PCR. In addition, shGhrelin showed reduced total ghrelin production and secretion (P<0.05) using ELISA in vitro. We also detected that GOAT mRNA expression was reduced in shGhrelin group (P<0.05), compared with control groups. In accordance with the GOAT expression, acylated ghrelin production and secretion were reduced in gastric mucosal cells and culture medium (P<0.05). Silencing of ghrelin gene achieved by RNAi-mediation inhibited the activity of H(+)-K(+)-ATPase and pepsin (P<0.05) in gastric mucosal cells. These results indicated that RNAi of Ghrelin gene inhibited the gastric acid secretion with decreased GOAT mRNA and acylated Ghrelin in gastric mucosal cells.
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Affiliation(s)
- Gai M Du
- Department of Animal Science and Technology, Jinling Technology Institution, Nanjing 210038, PR China
| | - Jie G Wu
- Department of Animal Science and Technology, Jinling Technology Institution, Nanjing 210038, PR China
| | - Bi P Luo
- Department of Animal Science and Technology, Jinling Technology Institution, Nanjing 210038, PR China
| | - Zhi H Hu
- Department of Animal Science and Technology, Jinling Technology Institution, Nanjing 210038, PR China
| | - Liu A Li
- Department of Animal Science, Tianjin Agricultural University, Tianjin 300384, PR China
| | - Mao J Liu
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, National Center for Engineering Research of Veterinary Bioproducts, Nanjing 210014, PR China.
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15
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Baumgartner CK, Zhang G, Kuether EL, Weiler H, Shi Q, Montgomery RR. Comparison of platelet-derived and plasma factor VIII efficacy using a novel native whole blood thrombin generation assay. J Thromb Haemost 2015; 13:2210-9. [PMID: 26453193 PMCID: PMC4715732 DOI: 10.1111/jth.13169] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 09/30/2015] [Indexed: 12/01/2022]
Abstract
BACKGROUND We have recently developed a successful gene therapy approach for hemophilia A in which factor VIII (FVIII) expression is targeted to platelets by the αIIb promoter. Levels of platelet-expressed FVIII (2bF8) achieved by gene therapy may vary between individuals due to differences in ex vivo transduction and gene expression efficiency. Accurate assays to evaluate 2bF8 efficacy are desirable. OBJECTIVE To compare the hemostatic efficacy of 2bF8 with replacement therapy over a wide therapeutic dose range. METHODS Efficacy of 2bF8 was assessed using a new transgenic mouse model expressing high 2bF8 levels (LV18(tg) ). Blood from LV18(tg) mice or FVIII(null) mice infused with recombinant FVIII was mixed with FVIII(null) blood at different ratios ex vivo to achieve several concentrations of 2bF8 or plasma FVIII. Samples were evaluated with a novel native whole blood thrombin generation assay that uses recalcified whole blood without the addition of tissue factor to initiate coagulation. RESULTS FVIII dose dependency was observed in all five thrombin generation parameters. While the total amount of thrombin generated was similar, 2bF8 significantly accelerated thrombin generation compared with plasma FVIII. Remarkably, a 10-fold lower dose of 2bF8 than plasma FVIII (0.2% vs. 2%) significantly shortened the onset and peak of thrombin generation compared with FVIII(null) blood. CONCLUSION Using a new transgenic mouse model, we showed that the novel native whole blood thrombin generation assay established here can be used to monitor platelet targeted FVIII gene therapy. The higher therapeutic efficacy of 2bF8 compared with factor replacement therapy seemed to be due to acceleration of thrombin generation.
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Affiliation(s)
- C K Baumgartner
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - G Zhang
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - E L Kuether
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - H Weiler
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
| | - Q Shi
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI, USA
| | - R R Montgomery
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
- Children's Research Institute, Children's Hospital of Wisconsin, Milwaukee, WI, USA
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Ortega EA, Ruthig VA, Ward MA. Sry-Independent Overexpression of Sox9 Supports Spermatogenesis and Fertility in the Mouse. Biol Reprod 2015; 93:141. [PMID: 26536904 DOI: 10.1095/biolreprod.115.135400] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/30/2015] [Indexed: 12/13/2022] Open
Abstract
The Y chromosome gene Sry is responsible for sex determination in mammals and initiates a cascade of events that direct differentiation of bipotential genital ridges toward male-specific fate. Sox9 is an autosomal gene and a primary downstream target of SRY. The activation of Sox9 in the absence of Sry is sufficient for initiation of male-specific sex determination. Sry-to-Sox9 replacement has mostly been studied in the context of sex determination during early embryogenesis. Here, we tested whether Sry-to-Sox9 replacement affects male fertility in adulthood. We examined males with the Y chromosome carrying a deletion removing the endogenous Sry, with testes determination driven either by the Sox9 (XY(Tdym1)Sox9) or the Sry (XY(Tdym1)Sry) transgenes as well as wild-type males (XY). XY(Tdym1)Sox9 males had reduced testes size, altered testes shape and vasculature, and increased incidence of defects in seminiferous epithelium underlying the coelomic blood vessel region when compared to XY(Tdym1)Sry and XY. There were no differences between XY(Tdym1)Sry and XY(Tdym1)Sox9 males in respect to sperm number, motility, morphology, and ability to fertilize oocytes in vitro, but for some parameters, transgenic males were impaired when compared to XY. In fecundity trials, XY(Tdym1)Sry, XY(Tdym1)Sox9, and XY males yielded similar average numbers of pups and litters. Overall, our findings support that males lacking the testis determinant Sry can be fertile and reinforce the notion that Sry does not play a role in mature gonads. Although transgenic Sox9 overexpression in the absence of Sry results in certain testicular abnormalities, it does not translate into fertility impairment.
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Affiliation(s)
- Egle A Ortega
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Victor A Ruthig
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Monika A Ward
- Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
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17
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RNAi-mediated gene silencing in zebrafish triggered by convergent transcription. Sci Rep 2014; 4:5222. [PMID: 24909225 PMCID: PMC4048883 DOI: 10.1038/srep05222] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/20/2014] [Indexed: 12/02/2022] Open
Abstract
RNAi based strategies to induce gene silencing are commonly employed in numerous model organisms but have not been extensively used in zebrafish. We found that introduction of transgenes containing convergent transcription units in zebrafish embryos induced stable transcriptional gene silencing (TGS) in cis and trans for reporter (mCherry) and endogenous (One-Eyed Pinhead (OEP) and miR-27a/b) genes. Convergent transcription enabled detection of both sense and antisense transcripts and silencing was suppressed upon Dicer knockdown, indicating processing of double stranded RNA. By ChIP analyses, increased silencing was accompanied by enrichment of the heterochromatin mark H3K9me3 in the two convergently arranged promoters and in the intervening reading frame. Our work demonstrates that convergent transcription can induce gene silencing in zebrafish providing another tool to create specific temporal and spatial control of gene expression.
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18
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Newhart A, Janicki SM. Seeing is believing: visualizing transcriptional dynamics in single cells. J Cell Physiol 2014; 229:259-65. [PMID: 23929405 DOI: 10.1002/jcp.24445] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 08/02/2013] [Indexed: 12/29/2022]
Abstract
For a gene to be expressed, the functions of multiple molecular machines must be coordinated at the site of transcription. To understand the role of nuclear organization in transcription, it is necessary to visualize the dynamic interactions of regulatory factors with chromatin and RNA. It is currently possible to localize individual transcription sites in single living mammalian cells by engineering reporter gene constructs to include sequence elements which permit the visualization of nucleic acids in vivo. Upon stable integration, these transgenes form chromatinized arrays, which can be imaged during activation to obtain high-resolution quantitative information about transcriptional dynamics. Modeling can suggest new hypotheses about gene regulation, which can be tested both in the single-cell imaging system and at endogenous genes. This gene-specific imaging strategy has the potential to reveal regulatory mechanisms, which would be difficult to imagine outside of single living cells.
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Affiliation(s)
- Alyshia Newhart
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania
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19
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Rauschhuber C, Ehrhardt A. RNA interference is responsible for reduction of transgene expression after Sleeping Beauty transposase mediated somatic integration. PLoS One 2012; 7:e35389. [PMID: 22570690 PMCID: PMC3343047 DOI: 10.1371/journal.pone.0035389] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 03/15/2012] [Indexed: 11/19/2022] Open
Abstract
Background Integrating non-viral vectors based on transposable elements are widely used for genetically engineering mammalian cells in functional genomics and therapeutic gene transfer. For the Sleeping Beauty (SB) transposase system it was demonstrated that convergent transcription driven by the SB transposase inverted repeats (IRs) in eukaryotic cells occurs after somatic integration. This could lead to formation of double-stranded RNAs potentially presenting targets for the RNA interference (RNAi) machinery and subsequently resulting into silencing of the transgene. Therefore, we aimed at investigating transgene expression upon transposition under RNA interference knockdown conditions. Principal Findings To establish RNAi knockdown cell lines we took advantage of the P19 protein, which is derived from the tomato bushy stunt virus. P19 binds and inhibits 21 nucleotides long, small-interfering RNAs and was shown to sufficiently suppress RNAi. We found that transgene expression upon SB mediated transposition was enhanced, resulting into a 3.2-fold increased amount of colony forming units (CFU) after transposition. In contrast, if the transgene cassette is insulated from the influence of chromosomal position effects by the chicken-derived cHS4 insulating sequences or when applying the Forg Prince transposon system, that displays only negligible transcriptional activity, similar numbers of CFUs were obtained. Conclusion In summary, we provide evidence for the first time that after somatic integration transposon derived transgene expression is regulated by the endogenous RNAi machinery. In the future this finding will help to further improve the molecular design of the SB transposase vector system.
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Affiliation(s)
- Christina Rauschhuber
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Anja Ehrhardt
- Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-University Munich, Munich, Germany
- Institute of Virology and Microbiology, Center for Biomedical Education and Research, Department of Human Medicine, Faculty of Health, University Witten/Herdecke, Witten, Germany
- * E-mail:
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Dávalos-Salas M, Furlan-Magaril M, González-Buendía E, Valdes-Quezada C, Ayala-Ortega E, Recillas-Targa F. Gain of DNA methylation is enhanced in the absence of CTCF at the human retinoblastoma gene promoter. BMC Cancer 2011; 11:232. [PMID: 21663659 PMCID: PMC3145615 DOI: 10.1186/1471-2407-11-232] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 06/10/2011] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Long-term gene silencing throughout cell division is generally achieved by DNA methylation and other epigenetic processes. Aberrant DNA methylation is now widely recognized to be associated with cancer and other human diseases. Here we addressed the contribution of the multifunctional nuclear factor CTCF to the epigenetic regulation of the human retinoblastoma (Rb) gene promoter in different tumoral cell lines. METHODS To assess the DNA methylation status of the Rb promoter, genomic DNA from stably transfected human erythroleukemic K562 cells expressing a GFP reporter transgene was transformed with sodium bisulfite, and then PCR-amplified with modified primers and sequenced. Single- and multi-copy integrants with the CTCF binding site mutated were isolated and characterized by Southern blotting. Silenced transgenes were reactivated using 5-aza-2'-deoxycytidine and Trichostatin-A, and their expression was monitored by fluorescent cytometry. Rb gene expression and protein abundance were assessed by RT-PCR and Western blotting in three different glioma cell lines, and DNA methylation of the promoter region was determined by sodium bisulfite sequencing, together with CTCF dissociation and methyl-CpG-binding protein incorporation by chromatin immunoprecipitation assays. RESULTS We found that the inability of CTCF to bind to the Rb promoter causes a dramatic loss of gene expression and a progressive gain of DNA methylation. CONCLUSIONS This study indicates that CTCF plays an important role in maintaining the Rb promoter in an optimal chromatin configuration. The absence of CTCF induces a rapid epigenetic silencing through a progressive gain of DNA methylation. Consequently, CTCF can now be seen as one of the epigenetic components that allows the proper configuration of tumor suppressor gene promoters. Its aberrant dissociation can then predispose key genes in cancer cells to acquire DNA methylation and epigenetic silencing.
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Affiliation(s)
- Mercedes Dávalos-Salas
- Instituto de Fisiología Celular, Departamento de Genética Molecular, Universidad Nacional Autónoma de México, México D.F., México
| | - Mayra Furlan-Magaril
- Instituto de Fisiología Celular, Departamento de Genética Molecular, Universidad Nacional Autónoma de México, México D.F., México
| | - Edgar González-Buendía
- Instituto de Fisiología Celular, Departamento de Genética Molecular, Universidad Nacional Autónoma de México, México D.F., México
| | - Christian Valdes-Quezada
- Instituto de Fisiología Celular, Departamento de Genética Molecular, Universidad Nacional Autónoma de México, México D.F., México
| | - Erandi Ayala-Ortega
- Instituto de Fisiología Celular, Departamento de Genética Molecular, Universidad Nacional Autónoma de México, México D.F., México
| | - Félix Recillas-Targa
- Instituto de Fisiología Celular, Departamento de Genética Molecular, Universidad Nacional Autónoma de México, México D.F., México
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Kirabo A, Oh SP, Kasahara H, Wagner KU, Sayeski PP. Vascular smooth muscle Jak2 deletion prevents angiotensin II-mediated neointima formation following injury in mice. J Mol Cell Cardiol 2011; 50:1026-34. [PMID: 21420414 DOI: 10.1016/j.yjmcc.2011.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 03/04/2011] [Accepted: 03/10/2011] [Indexed: 01/17/2023]
Abstract
The in vitro treatment of vascular smooth muscle cells (VSMC) with angiotensin II (Ang II) causes Janus kinase 2 (Jak2) to interact with the Ang II type 1 receptor (AT(1)-R) resulting in enhanced cell growth. However, the role that Jak2 plays in AT(1)-R-mediated vascular cell growth and remodeling in vivo is less clear. We hypothesized that in vivo, Jak2 plays a rate-limiting role in Ang II-mediated neointima formation following vascular injury. Using the Cre-loxP system, we conditionally ablated Jak2 from the VSMC of mice. We found that these mice are protected from Ang II-mediated neointima formation following iron chloride-induced vascular injury. In addition, the VSMC Jak2 null mice were protected from injury-induced vascular fibrosis and the pathological loss of the contractile marker, smooth muscle α-actin. Finally, when compared to controls, the VSMC Jak2 null mice exhibited significantly less Ang II-induced VSMC proliferation and migration in vitro and in vivo and more apoptosis. These results suggest that Jak2 plays a central role in the causation of Ang II-induced neointima formation following vascular injury and may provide a novel target for the prevention of neointima formation.
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Affiliation(s)
- Annet Kirabo
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610, USA
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