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Feng J, Wang Q, Qin Z, Guo X, Fu H, Yang ST, Wang J. Development of inducible promoters for regulating gene expression in Clostridium tyrobutyricum for biobutanol production. Biotechnol Bioeng 2024; 121:1518-1531. [PMID: 38548678 DOI: 10.1002/bit.28701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/29/2023] [Accepted: 01/03/2024] [Indexed: 04/14/2024]
Abstract
Clostridium tyrobutyricum is an anaerobe known for its ability to produce short-chain fatty acids, alcohols, and esters. We aimed to develop inducible promoters for fine-tuning gene expression in C. tyrobutyricum. Synthetic inducible promoters were created by employing an Escherichia coli lac operator to regulate the thiolase promoter (PCathl) from Clostridium acetobutylicum, with the best one (LacI-Pto4s) showing a 5.86-fold dynamic range with isopropyl β- d-thiogalactoside (IPTG) induction. A LT-Pt7 system with a dynamic range of 11.6-fold was then created by combining LacI-Pto4s with a T7 expression system composing of RNA polymerase (T7RNAP) and Pt7lac promoter. Furthermore, two inducible expression systems BgaR-PbgaLA and BgaR-PbgaLB with a dynamic range of ~40-fold were developed by optimizing a lactose-inducible expression system from Clostridium perfringens with modified 5' untranslated region (5' UTR) and ribosome-binding site (RBS). BgaR-PbgaLB was then used to regulate the expressions of a bifunctional aldehyde/alcohol dehydrogenase encoded by adhE2 and butyryl-CoA/acetate Co-A transferase encoded by cat1 in C. tyrobutyricum wild type and Δcat1::adhE2, respectively, demonstrating its efficient inducible gene regulation. The regulated cat1 expression also confirmed that the Cat1-catalyzed reaction was responsible for acetate assimilation in C. tyrobutyricum. The inducible promoters offer new tools for tuning gene expression in C. tyrobutyricum for industrial applications.
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Affiliation(s)
- Jun Feng
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Qingke Wang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Zhen Qin
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Xiaolong Guo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Hongxin Fu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shang-Tian Yang
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou, China
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Düchs MJ, Kratzer RF, Vieyra-Garcia P, Strobel B, Schönberger T, Groß P, Aljayyoussi G, Gupta A, Lang I, Klein H, Morilla SM, Hopf S, Park J, Kreuz S, Klugmann M, Igney FH. Riboswitch-controlled IL-12 gene therapy reduces hepatocellular cancer in mice. Front Immunol 2024; 15:1360063. [PMID: 38558809 PMCID: PMC10979303 DOI: 10.3389/fimmu.2024.1360063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/14/2024] [Indexed: 04/04/2024] Open
Abstract
Hepatocellular carcinoma (HCC) and solid cancers with liver metastases are indications with high unmet medical need. Interleukin-12 (IL-12) is a proinflammatory cytokine with substantial anti-tumor properties, but its therapeutic potential has not been realized due to severe toxicity. Here, we show that orthotopic liver tumors in mice can be treated by targeting hepatocytes via systemic delivery of adeno-associated virus (AAV) vectors carrying the murine IL-12 gene. Controlled cytokine production was achieved in vivo by using the tetracycline-inducible K19 riboswitch. AAV-mediated expression of IL-12 led to STAT4 phosphorylation, interferon-γ (IFNγ) production, infiltration of T cells and, ultimately, tumor regression. By detailed analyses of efficacy and tolerability in healthy and tumor-bearing animals, we could define a safe and efficacious vector dose. As a potential clinical candidate, we characterized vectors carrying the human IL-12 (huIL-12) gene. In mice, bioactive human IL-12 was expressed in a vector dose-dependent manner and could be induced by tetracycline, suggesting tissue-specific AAV vectors with riboswitch-controlled expression of highly potent proinflammatory cytokines as an attractive approach for vector-based cancer immunotherapy.
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Affiliation(s)
- Matthias J. Düchs
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Ramona F. Kratzer
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Pablo Vieyra-Garcia
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria
| | - Benjamin Strobel
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Tanja Schönberger
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Peter Groß
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Ghaith Aljayyoussi
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Aradhana Gupta
- Nonclinical Drug Safety, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, United States
| | - Isabel Lang
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Holger Klein
- Global Computational Biology and Digital Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Sandra Martinez Morilla
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim RCV GmbH & Co. KG, Ridgefield, CT, United States
| | - Stefan Hopf
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria
| | - John Park
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Sebastian Kreuz
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Matthias Klugmann
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Frederik H. Igney
- Cancer Immunology and Immune Modulation, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
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Gödecke N, Herrmann S, Weichelt V, Wirth D. A Ubiquitous Chromatin Opening Element and DNA Demethylation Facilitate Doxycycline-Controlled Expression during Differentiation and in Transgenic Mice. ACS Synth Biol 2023; 12:482-491. [PMID: 36755406 PMCID: PMC9942253 DOI: 10.1021/acssynbio.2c00450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Synthetic expression cassettes provide the ability to control transgene expression in experimental animal models through external triggers, enabling the study of gene function and the modulation of endogenous regulatory networks in vivo. The performance of synthetic expression cassettes in transgenic animals critically depends on the regulatory properties of the respective chromosomal integration sites, which are affected by the remodeling of the chromatin structure during development. The epigenetic status may affect the transcriptional activity of the synthetic cassettes and even lead to transcriptional silencing, depending on the chromosomal sites and the tissue. In this study, we investigated the influence of the ubiquitous chromosome opening element (UCOE) HNRPA2B1-CBX3 and its subfragments A2UCOE and CBX3 on doxycycline-controlled expression modules within the chromosomal Rosa26 locus. While HNRPA2B1-CBX3 and A2UCOE reduced the expression of the synthetic cassettes in mouse embryonic stem cells, CBX3 stabilized the expression and facilitated doxycycline-controlled expression after in vitro differentiation. In transgenic mice, the CBX3 element protected the cassettes from overt silencing although the expression was moderate and only partially controlled by doxycycline. We demonstrate that CBX3-flanked synthetic cassettes can be activated by decitabine-mediated blockade of DNA methylation or by specific recruitment of the catalytic demethylation domain of the ten-eleven translocation protein TET1 to the synthetic promoter. This suggests that CBX3 renders the synthetic cassettes permissive for subsequent epigenetic activation, thereby supporting doxycycline-controlled expression. Together, this study reveals a strategy for overcoming epigenetic constraints of synthetic expression cassettes, facilitating externally controlled transgene expression in mice.
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Affiliation(s)
- Natascha Gödecke
- RG
Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Sabrina Herrmann
- RG
Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Viola Weichelt
- RG
Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Dagmar Wirth
- RG
Model Systems for Infection and Immunity, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany,Institute
of Experimental Hematology, Medical University
Hannover (MHH), 30625 Hannover, Germany,
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Zhang M, Luo Q, Sun H, Fritze J, Luan G, Lu X. Engineering a Controllable Targeted Protein Degradation System and a Derived OR-GATE-Type Inducible Gene Expression System in Synechococcus elongatus PCC 7942. ACS Synth Biol 2022; 11:125-134. [PMID: 34914362 DOI: 10.1021/acssynbio.1c00226] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cyanobacteria are important model organisms for exploring the mechanisms of photosynthesis and are considered as promising microbial platforms for photosynthetic biomanufacturing. The development of efficient cyanobacteria cell factories requires efficient and convenient tools to dynamically regulate and manipulate target proteins, modules, and pathways. Targeted protein degradation is important to achieve rapid responses of cellular metabolic networks to artificial or environmental signals, and there are currently limited approaches to induce protein degradation in cyanobacteria. In this work, we developed an Escherichia coli sourced ssrA-tagging system in an important cyanobacteria strain, Synechococcus elongatus PCC 7942, to achieve inducible degradation of target proteins. A modified version of the E. coli ssrA tag (ssrADAS) proved to be immune to the native ClpXP system in Synechococcus elongatus PCC 7942, while induced expression of the E. coli sourced adaptor SspB and ClpXP resulted in effective degradation of the tagged proteins. Compared to the previously developed down-regulation approaches, the inducible ssrADAS-SspB-ClpXPEc system facilitated the smart and rapid degradation of target proteins in PCC7942 cells at different growth stages. Furthermore, when used to regulate the degradation of LacI, the repressor element of LacO-LacI transcription regulation system, an efficient and stringent inducible gene expression system was obtained based on an OR-GATE type genetic circuit design. The tools developed in this work expanded the cyanobacteria synthetic biology toolbox and will facilitate the success of future dynamic metabolic engineering.
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Affiliation(s)
- Mingyi Zhang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Quan Luo
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Huili Sun
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jacques Fritze
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, China
- University of Stuttgart, Stuttgart, 70174, Germany
| | - Guodong Luan
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Xuefeng Lu
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
- Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
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Omenge KM, Rümpler F, Kathalingam SS, Furch ACU, Theißen G. Studying the Function of Phytoplasma Effector Proteins Using a Chemical-Inducible Expression System in Transgenic Plants. Int J Mol Sci 2021; 22:ijms222413582. [PMID: 34948378 PMCID: PMC8703313 DOI: 10.3390/ijms222413582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022] Open
Abstract
Phytoplasmas are bacterial pathogens that live mainly in the phloem of their plant hosts. They dramatically manipulate plant development by secreting effector proteins that target developmental proteins of their hosts. Traditionally, the effects of individual effector proteins have been studied by ectopic overexpression using strong, ubiquitously active promoters in transgenic model plants. However, the impact of phytoplasma infection on the host plants depends on the intensity and timing of infection with respect to the developmental stage of the host. To facilitate investigations addressing the timing of effector protein activity, we have established chemical-inducible expression systems for the three most well-characterized phytoplasma effector proteins, SECRETED ASTER YELLOWS WITCHES’ BROOM PROTEIN 11 (SAP11), SAP54 and TENGU in transgenic Arabidopsis thaliana. We induced gene expression either continuously, or at germination stage, seedling stage, or flowering stage. mRNA expression was determined by quantitative reverse transcription PCR, protein accumulation by confocal laser scanning microscopy of GFP fusion proteins. Our data reveal tight regulation of effector gene expression and strong upregulation after induction. Phenotypic analyses showed differences in disease phenotypes depending on the timing of induction. Comparative phenotype analysis revealed so far unreported similarities in disease phenotypes, with all three effector proteins interfering with flower development and shoot branching, indicating a surprising functional redundancy of SAP54, SAP11 and TENGU. However, subtle but mechanistically important differences were also observed, especially affecting the branching pattern of the plants.
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Affiliation(s)
- Keziah M. Omenge
- Department of Genetics, Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Philosophenweg 12, 07743 Jena, Germany; (K.M.O.); (F.R.); (S.S.K.)
| | - Florian Rümpler
- Department of Genetics, Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Philosophenweg 12, 07743 Jena, Germany; (K.M.O.); (F.R.); (S.S.K.)
| | - Subha Suvetha Kathalingam
- Department of Genetics, Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Philosophenweg 12, 07743 Jena, Germany; (K.M.O.); (F.R.); (S.S.K.)
| | - Alexandra C. U. Furch
- Department of Plant Physiology, Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Dornburger Str. 159, 07743 Jena, Germany;
| | - Günter Theißen
- Department of Genetics, Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Philosophenweg 12, 07743 Jena, Germany; (K.M.O.); (F.R.); (S.S.K.)
- Correspondence:
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Wang F, Ji YT, Tian C, Wang YC, Xu S, Wang RY, Yang QQ, Zhao P, Xia QY. An inducible constitutive expression system in Bombyx mori mediated by phiC31 integrase. Insect Sci 2021; 28:1277-1289. [PMID: 32803790 DOI: 10.1111/1744-7917.12866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Inducible gene-expression systems play important roles in gene functional assays in the post-genome era. Streptomyces phage-derived phiC31 integrase, which mediates an irreversible site-specific cassette exchange between the phage attachment site (attP) and the bacterial attachment site (attB), provides a promising option for the construction of a controllable gene-expression system. Here, we report a phiC31 integrase-mediated promoter flip system (FLIP) for the inducible expression of target genes in silkworm (Bombyx mori). First, we constructed a FLIP reporter system, in which a BmAct4 promoter with enhanced translational efficiency was flanked by the attB and attP sites in a head-to-head orientation and further linked in a reverse orientation to a DsRed reporter gene. The coexpression of a C-terminal modified phiC31-NLS integrase carrying a simian virus 40 (SV40) nuclear localization signal (NLS) effectively flipped the BmAct4 promoter through an attB/attP exchange, thereby activating the downstream expression of DsRed in a silkworm embryo-derived cell line, BmE. Subsequently, the FLIP system, together with a system continuously expressing the phiC31-NLS integrase, was used to construct binary transgenic silkworm lines. Hybridization between FLIP and phiC31-NLS transgenic silkworm lines resulted in the successful flipping of the BmAct4 promoter, with an approximately 39% heritable transformation efficiency in silkworm offspring, leading to the constitutive and high-level expression of DsRed in silkworms, which accounted for approximately 0.81% of the silkworm pupal weight. Our successful development of the FLIP system offers an effective alternative for manipulating gene expression in silkworms and other lepidopteran species.
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Affiliation(s)
- Feng Wang
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Yan-Ting Ji
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Chi Tian
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Yuan-Cheng Wang
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Shen Xu
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Ri-Yuan Wang
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Qian-Qian Yang
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
| | - Qing-You Xia
- State Key Laboratory of Silkworm Genome Biology, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Biological Science Research Center, Southwest University, Chongqing, China
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Nistal-Villán E, Argemi J, de Jaime-Soguero A, Ferrero R, di Scala M, Rodriguez-Garcia E, Coll A, Rius-Rocabert S, Prieto J, González-Aseguinolaza G, Aragón T. Linking the Expression of Therapeutic Genes to Unfolded Protein Response: A New Option for Anti-Hepatitis B Virus Gene Therapy. Hum Gene Ther 2021; 32:341-348. [PMID: 33213214 DOI: 10.1089/hum.2019.336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tight control of transgene expression is key to ensure the efficacy of a wide range of gene therapy interventions, in which the magnitude and duration of gene expression have to be adjusted to therapeutic needs, thereby limiting secondary effects. The development of upgraded strategies to link transgene expression to pathological stress episodes is an unmet need in gene therapy. Here, we propose an expression strategy that associates transgene expression to an intracellular stress coping mechanism, the unfolded protein response. Specifically, we harnessed the cis elements required to sustain the noncanonical splicing of X-box binding protein 1 (XBP1) messenger RNA (mRNA) in response to the dysfunction of the endoplasmic reticulum (ER), a situation commonly known as ER stress, to drive the expression of heterologous genes. Since ER stress features a wide variety of pathological conditions, including viral infections, cancer, or metabolic disorders, this new expression module stimulates the synthesis of therapeutic genes as a response to cellular damage, and ensures their expression only when necessary. Validation of this inducible expression system was performed in vitro and in vivo, and its potential to limit/inhibit viral infections has been shown in proof-of principle experiments.
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Affiliation(s)
- Estanislao Nistal-Villán
- Microbiology Section, Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
- Facultad de Medicina, Instituto de Medicina Molecular Aplicada (IMMA), Universidad San Pablo-CEU, Madrid, Spain
| | - Josepmaria Argemi
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Anchel de Jaime-Soguero
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Roberto Ferrero
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Marianna di Scala
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Estefania Rodriguez-Garcia
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Aniol Coll
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Sergio Rius-Rocabert
- Microbiology Section, Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
- Facultad de Medicina, Instituto de Medicina Molecular Aplicada (IMMA), Universidad San Pablo-CEU, Madrid, Spain
- Centre for Metabolomics and Bioanalysis (CEMBIO), Facultad de Farmacia, Universidad San Pablo-CEU, Madrid, Spain
| | - Jesús Prieto
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Gloria González-Aseguinolaza
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
| | - Tomás Aragón
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
- Navarra Institute for Health Research (IdiSNA), Pamplona, Spain
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Guan L, Lu R, Wu Z, Zhong G, Zhang S. Precise Expression of Afmed15 Is Crucial for Asexual Development, Virulence, and Survival of Aspergillus fumigatus. mSphere 2020; 5:e00771-20. [PMID: 33028685 DOI: 10.1128/mSphere.00771-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The identification and characterization of regulators essential for virulence or development constitute one approach for antifungal drug development. In this study, we screened and functionally characterized Afmed15, a novel developmental regulator in A. fumigatus. We demonstrate that the precise transcriptional expression of Afmed15 is crucial for fungal asexual development, virulence, and survival. Downregulating the expression of Afmed15 abolished the conidiation and decreased the fungal virulence in an insect model. In contrast, the overexpression of Afmed15 caused fungal death accompanied by intensive autophagy. Our study provides a foundation for further studies to identify compounds perturbing the expression of Afmed15 that may be used for the prevention of invasive A. fumigatus infections. The rise of drug resistance in fungal pathogens is becoming a serious problem owing to the limited number of antifungal drugs available. Identifying and targeting factors essential for virulence or development unique to fungal pathogens is one approach to develop novel treatments for fungal infections. In this study, we present the identification and functional characterization of a novel developmental regulator in Aspergillus fumigatus, AfMed15, which contained a conserved Med15_fungal domain, as determined by screening of a mutant library that contained more than 2,000 hygromycin-resistant A. fumigatus transformants. Downregulating the expression of Afmed15 abolished the conidiation and decreased the fungal virulence in an insect model. Strikingly, the overexpression of Afmed15 caused fungal death accompanied by intensive autophagy. RNA sequencing of an Afmed15 overexpression strain revealed that altered gene expression patterns were associated with carbon metabolism, energy metabolism, and translation. Interestingly, the addition of metal ions could partially rescue fungal death caused by the overexpression of Afmed15, indicating that disordered ion homeostasis is a potential reason for the fungal death caused by the overexpression of Afmed15. Considering that the precise expression of Afmed15 is crucial for fungal development, virulence, and survival and that no ortholog was found in humans, Afmed15 is an ideal target for antifungal-drug development. IMPORTANCE The identification and characterization of regulators essential for virulence or development constitute one approach for antifungal drug development. In this study, we screened and functionally characterized Afmed15, a novel developmental regulator in A. fumigatus. We demonstrate that the precise transcriptional expression of Afmed15 is crucial for fungal asexual development, virulence, and survival. Downregulating the expression of Afmed15 abolished the conidiation and decreased the fungal virulence in an insect model. In contrast, the overexpression of Afmed15 caused fungal death accompanied by intensive autophagy. Our study provides a foundation for further studies to identify compounds perturbing the expression of Afmed15 that may be used for the prevention of invasive A. fumigatus infections.
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Camilo Galindo C, Arturo Clavijo-Ramírez C. Generation and characterization of U937-TR: a platform cell line for inducible gene expression in human macrophages. Parasitology 2020; 147:1524-31. [PMID: 32713391 DOI: 10.1017/S0031182020001110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Monocytes and macrophages are involved in a wide range of biological processes and parasitic diseases. The characterization of the molecular mechanisms governing such processes usually requires precise control of the expression of genes of interest. We implemented a tetracycline-controlled gene expression system in the U937 cell line, one of the most used in vitro models for the research of human monocytes and macrophages. Here we characterized U937-derived cell lines in terms of phenotypic (morphology and marker expression) and functional (capacity for phagocytosis and for Leishmania parasite hosting) changes induced by phorbol-12-myristate-13-acetate (PMA). Finally, we provide evidence of tetracycline-inducible and reversible Lamin-A gene silencing of the PMA-differentiated U937-derived cells.
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10
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Strobel B, Düchs MJ, Blazevic D, Rechtsteiner P, Braun C, Baum-Kroker KS, Schmid B, Ciossek T, Gottschling D, Hartig JS, Kreuz S. A Small-Molecule-Responsive Riboswitch Enables Conditional Induction of Viral Vector-Mediated Gene Expression in Mice. ACS Synth Biol 2020; 9:1292-1305. [PMID: 32427483 DOI: 10.1021/acssynbio.9b00410] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Adeno-associated viral (AAV) vector-mediated gene therapy holds great potential for future medical applications. However, to facilitate safer and broader applicability and to enable patient-centric care, therapeutic protein expression should be controllable, ideally by an orally administered drug. The use of protein-based systems is considered rather undesirable, due to potential immunogenicity and the limited coding space of AAV. Ligand-dependent riboswitches, in contrast, are small and characterized by an attractive mode-of-action based on mRNA-self-cleavage, independent of coexpressed foreign protein. While a promising approach, switches available to date have only shown moderate potency in animals. In particular, ON-switches that induce transgene expression upon ligand administration so far have achieved rather disappointing results. Here we present the utilization of the previously described tetracycline-dependent ribozyme K19 for controlling AAV-mediated transgene expression in mice. Using this tool switch, we provide first proof for the feasibility of clinically desired key features, including multiorgan functionality, potent regulation (up to 15-fold induction), reversibility, and the possibility to fine-tune and repeatedly induce expression. The systematic assessment of ligand and reporter protein plasma levels further enabled the characterization of pharmacokinetic-pharmacodynamic relationships. Thus, our results strongly support future efforts to develop engineered riboswitches for applications in clinical gene therapy.
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Affiliation(s)
- Benjamin Strobel
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Matthias J. Düchs
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Dragica Blazevic
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Philipp Rechtsteiner
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Clemens Braun
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Katja S. Baum-Kroker
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Bernhard Schmid
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Thomas Ciossek
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Dirk Gottschling
- Medicinal Chemistry, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
| | - Jörg S. Hartig
- Department of Chemistry, University of Konstanz, Konstanz, 78464, Germany
| | - Sebastian Kreuz
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, 88397, Germany
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11
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Stewart JIP, Fava VM, Kerkaert JD, Subramanian AS, Gravelat FN, Lehoux M, Howell PL, Cramer RA, Sheppard DC. Reducing Aspergillus fumigatus Virulence through Targeted Dysregulation of the Conidiation Pathway. mBio 2020; 11:e03202-19. [PMID: 32019801 DOI: 10.1128/mBio.03202-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Inhalation of conidia of the opportunistic mold Aspergillus fumigatus by immunocompromised hosts can lead to invasive pulmonary disease. Inhaled conidia that escape immune defenses germinate to form filamentous hyphae that invade lung tissues. Conidiation rarely occurs during invasive infection of the human host, allowing the bulk of fungal energy to be directed toward vegetative growth. We hypothesized that forced induction of conidiation during infection can suppress A. fumigatus vegetative growth, impairing the ability of this organism to cause disease. To study the effects of conidiation pathway dysregulation on A. fumigatus virulence, a key transcriptional regulator of conidiation (brlA) was expressed under the control of a doxycycline-inducible promoter. Time- and dose-dependent brlA overexpression was observed in response to doxycycline both in vitro and in vivo. Exposure of the inducible brlA overexpression strain to low doses of doxycycline under vegetative growth conditions in vitro induced conidiation, whereas high doses arrested growth. Overexpression of brlA attenuated A. fumigatus virulence in both an invertebrate and mouse model of invasive aspergillosis. RNA sequencing studies and phenotypic analysis revealed that brlA overexpression results in altered cell signaling, amino acid, and carbohydrate metabolism, including a marked upregulation of trehalose biosynthesis and a downregulation in the biosynthesis of the polysaccharide virulence factor galactosaminogalactan. This proof of concept study demonstrates that activation of the conidiation pathway in A. fumigatus can reduce virulence and suggests that brlA-inducing small molecules may hold promise as a new class of therapeutics for A. fumigatus infection.IMPORTANCE The mold Aspergillus fumigatus reproduces by the production of airborne spores (conidia), a process termed conidiation. In immunocompromised individuals, inhaled A. fumigatus conidia can germinate and form filaments that penetrate and damage lung tissues; however, conidiation does not occur during invasive infection. In this study, we demonstrate that forced activation of conidiation in filaments of A. fumigatus can arrest their growth and impair the ability of this fungus to cause disease in both an insect and a mouse model of invasive infection. Activation of conidiation was linked to profound changes in A. fumigatus metabolism, including a shift away from the synthesis of polysaccharides required for cell wall structure and virulence in favor of carbohydrates used for energy storage and stress resistance. Collectively, these findings suggest that activation of the conidiation pathway may be a promising approach for the development of new agents to prevent or treat A. fumigatus infection.
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12
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Ramesh A, Ikeda N, Rubinchik S, Karlyshev AV. Expression of Escherichia coli araE and modified lacY genes in Campylobacter jejuni is not sufficient for arabinose transport. Access Microbiol 2019; 1:e000042. [PMID: 32974528 PMCID: PMC7470287 DOI: 10.1099/acmi.0.000042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/24/2019] [Indexed: 11/18/2022] Open
Abstract
Introduction Unlike Escherichia coli, Campylobacter jejuni is unable to import a range of sugars, including arabinose, which makes common expression vectors, such as pBAD33, non-functional in these bacteria. Aim The aim of this study was to investigate whether the E. coli transporters AraE and modified LacY (LacYA177C) would enable C. jejuni to uptake arabinose. Methodology and Results The respective genes of E. coli were constitutively expressed in C. jejuni strain 11168H after integration into the chromosome via homologous recombination. Vectors carrying these genes also contained a reporter gene, gfp, under the control of the arabinose-inducible promoter, pBAD. These constructs were verified in E. coli by demonstrating the induction of gfp in the presence of arabinose. Integration of the genes into one of the rRNA gene clusters was verified by PCR and genome sequencing. The latter also confirmed that the inserted gene clusters contained no mutations. Expression of the gfp gene in the presence of arabinose inducer was monitored using fluorescence microscopy of colonies and fluorimetry using both whole cells and lysates. Conclusion The results demonstrated the inability of C. jejuni to use arabinose transporters, which are fully functional in E. coli, suggesting a remarkable difference in the physiology of these bacteria.
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Affiliation(s)
- Amritha Ramesh
- SEC Faculty, Kingston University, Kingston upon Thames, Penrhyn Road, KT1 2EE, UK
| | - Naomi Ikeda
- SEC Faculty, Kingston University, Kingston upon Thames, Penrhyn Road, KT1 2EE, UK
| | - Sona Rubinchik
- SEC Faculty, Kingston University, Kingston upon Thames, Penrhyn Road, KT1 2EE, UK
| | - Andrey V Karlyshev
- SEC Faculty, Kingston University, Kingston upon Thames, Penrhyn Road, KT1 2EE, UK
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13
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Uchibori R, Teruya T, Ido H, Ohmine K, Sehara Y, Urabe M, Mizukami H, Mineno J, Ozawa K. Functional Analysis of an Inducible Promoter Driven by Activation Signals from a Chimeric Antigen Receptor. Mol Ther Oncolytics 2018; 12:16-25. [PMID: 30662937 PMCID: PMC6325072 DOI: 10.1016/j.omto.2018.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 11/27/2018] [Indexed: 01/07/2023]
Abstract
Adoptive transfer of T cells expressing a chimeric antigen receptor (CAR) is a promising cell-based anticancer therapy. Although clinical studies of this approach show therapeutic efficacy, additional genetic modification is necessary to enhance the efficacy and safety of CAR-T cells. For example, production of an antitumor cytokine from CAR-T cells can potentially enhance their tumor-killing activity, but there are concerns that constitutive expression of anticancer molecules will cause systemic side effects. Therefore, it is important that exogenous gene expression is confined to the tumor locality. Here, we aimed to develop an inducible promoter driven by activation signals from a CAR. Transgene expression in T cells transduced with the CD19-targeted CAR and an inducible promoter, including inducible reporter genes (CAR-T/iReporter), was only induced strongly by co-culture with CD19-positive target cells. CAR-T/iReporter cells also showed redirected cytolysis toward CD19-positive, but not CD19-negative, tumor cells. Overall, our study indicated that the inducible promoter was selectively driven by activation signals from the CAR, and transduction with the inducible promoter did not affect original effector activities including interleukin-2 and interferon-γ production and the antitumor activity of CAR-redirected cytotoxic T lymphocytes. Moreover, this inducible promoter permits visualization and quantification of the activation status in CAR-T cells.
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Affiliation(s)
- Ryosuke Uchibori
- Division of Immuno-Gene and Cell Therapy, Jichi Medical University, Shimotsuke, Japan.,Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Takeshi Teruya
- Division of Immuno-Gene and Cell Therapy, Jichi Medical University, Shimotsuke, Japan.,CDM Center, Takara Bio Inc., Kusatsu, Japan
| | - Hiroyuki Ido
- Division of Immuno-Gene and Cell Therapy, Jichi Medical University, Shimotsuke, Japan.,CDM Center, Takara Bio Inc., Kusatsu, Japan
| | - Ken Ohmine
- Division of Immuno-Gene and Cell Therapy, Jichi Medical University, Shimotsuke, Japan.,Division of Hematology, Department of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Yoshihide Sehara
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Masashi Urabe
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Hiroaki Mizukami
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan
| | | | - Keiya Ozawa
- Division of Immuno-Gene and Cell Therapy, Jichi Medical University, Shimotsuke, Japan
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14
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Abstract
Itaconic acid is an important platform chemical that can easily be incorporated into polymers and has the potential to replace petrochemical-based acrylic or methacrylic acid. A number of microorganisms have been developed for the biosynthesis of itaconate including Aspergillus terreus, Escherichia coli, and Saccharomyces cerevisiae. However, the number of strains and conditions that can be tested for increased itaconate titers are currently limited because of the lack of high-throughput screening methods. Here we identified itaconate-inducible promoters and their corresponding LysR-type transcriptional regulators from Yersinia pseudotuberculosis and Pseudomonas aeruginosa. We show that the YpItcR/P ccl inducible system is highly inducible by itaconic acid in the model gammaproteobacterium E. coli and the betaproteobacterium Cupriavidus necator (215- and 105-fold, respectively). The kinetics and dynamics of the YpItcR/P ccl inducible system are investigated, and we demonstrate, that in addition to itaconate, the genetically encoded biosensor is capable of detecting mesaconate, cis-, and trans-aconitate in a dose-dependent manner. Moreover, the fluorescence-based biosensor is applied in E. coli to identify the optimum expression level of cadA, the product of which catalyzes the conversion of cis-aconitate into itaconate. The fluorescence output is shown to correlate well with itaconate concentrations quantified using high-performance liquid chromatography coupled with ultraviolet spectroscopy. This work highlights the potential of the YpItcR/P ccl inducible system to be applied as a biosensor for high-throughput microbial strain development to facilitate improved itaconate biosynthesis.
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Affiliation(s)
- Erik K.
R. Hanko
- BBSRC/EPSRC
Synthetic Biology Research Centre (SBRC), School of Life Sciences,
Centre for Biomolecular Sciences, The University
of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Nigel P. Minton
- BBSRC/EPSRC
Synthetic Biology Research Centre (SBRC), School of Life Sciences,
Centre for Biomolecular Sciences, The University
of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Naglis Malys
- BBSRC/EPSRC
Synthetic Biology Research Centre (SBRC), School of Life Sciences,
Centre for Biomolecular Sciences, The University
of Nottingham, Nottingham, NG7 2RD, United Kingdom
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15
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Luger AL, Sauer B, Lorenz NI, Engel AL, Braun Y, Voss M, Harter PN, Steinbach JP, Ronellenfitsch MW. Doxycycline Impairs Mitochondrial Function and Protects Human Glioma Cells from Hypoxia-Induced Cell Death: Implications of Using Tet-Inducible Systems. Int J Mol Sci 2018; 19:E1504. [PMID: 29772845 DOI: 10.3390/ijms19051504] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/30/2018] [Accepted: 05/15/2018] [Indexed: 01/30/2023] Open
Abstract
Inducible gene expression is an important tool in molecular biology research to study protein function. Most frequently, the antibiotic doxycycline is used for regulation of so-called tetracycline (Tet)-inducible systems. In contrast to stable gene overexpression, these systems allow investigation of acute and reversible effects of cellular protein induction. Recent reports have already called for caution when using Tet-inducible systems as the employed antibiotics can disturb mitochondrial function and alter cellular metabolism by interfering with mitochondrial translation. Reprogramming of energy metabolism has lately been recognized as an important emerging hallmark of cancer and is a central focus of cancer research. Therefore, the scope of this study was to systematically analyze dose-dependent metabolic effects of doxycycline on a panel of glioma cell lines with concomitant monitoring of gene expression from Tet-inducible systems. We report that doxycycline doses commonly used with inducible expression systems (0.01–1 µg/mL) substantially alter cellular metabolism: Mitochondrial protein synthesis was inhibited accompanied by reduced oxygen and increased glucose consumption. Furthermore, doxycycline protected human glioma cells from hypoxia-induced cell death. An impairment of cell growth was only detectable with higher doxycycline doses (10 µg/mL). Our findings describe settings where doxycycline exerts effects on eukaryotic cellular metabolism, limiting the employment of Tet-inducible systems.
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16
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Hubner EK, Lechler C, Kohnke-Ertel B, Zmoos AF, Sage J, Schmid RM, Ehmer U. An in vivo transfection system for inducible gene expression and gene silencing in murine hepatocytes. J Gene Med 2018; 19. [PMID: 28009940 DOI: 10.1002/jgm.2940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 12/21/2016] [Accepted: 12/21/2016] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Hydrodynamic tail vein injection (HTVI) of transposon-based integration vectors is an established system for stably transfecting mouse hepatocytes in vivo that has been successfully employed to study key questions in liver biology and cancer. Refining the vectors for transposon-mediated hepatocyte transfection will further expand the range of applications of this technique in liver research. In the present study, we report an advanced transposon-based system for manipulating gene expression in hepatocytes in vivo. METHODS Transposon-based vector constructs were generated to enable the constitutive expression of inducible Cre recombinase (CreER) together with tetracycline-inducible transgene or miR-small hairpin RNA (shRNA) expression (Tet-ON system). Transposon and transposase expression vectors were co-injected into R26R-mTmG reporter mice by HTVI. Cre-mediated gene recombination was induced by tamoxifen, followed by the administration of doxycycline to drive tetracycline-inducible gene or shRNA expression. Expression was visualized by immunofluorescence staining in livers of injected mice. RESULTS After HTVI, Cre recombination by tamoxifen led to the expression of membrane-bound green fluorescent protein in transfected hepatocytes. Activation of inducible gene or shRNA expression was detected by immunostaining in up to one-third of transfected hepatocytes, with an efficiency dependent on the promoter driving the Tet-ON system. CONCLUSIONS Our vector system combines Cre-lox mediated gene mutation with inducible gene expression or gene knockdown, respectively. It provides the opportunity for rapid and specific modification of hepatocyte gene expression and can be a useful tool for genetic screening approaches and analysis of target genes specifically in genetically engineered mouse models.
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Affiliation(s)
- Eric K Hubner
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Christian Lechler
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Birgit Kohnke-Ertel
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Anne-Flore Zmoos
- Department of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Julien Sage
- Department of Pediatrics and Genetics, Stanford University School of Medicine, Stanford, California, USA
| | - Roland M Schmid
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Ursula Ehmer
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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Nonogaki M, Nonogaki H. Prevention of Preharvest Sprouting through Hormone Engineering and Germination Recovery by Chemical Biology. Front Plant Sci 2017; 8:90. [PMID: 28197165 PMCID: PMC5281562 DOI: 10.3389/fpls.2017.00090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 01/16/2017] [Indexed: 05/08/2023]
Abstract
Vivipary, germination of seeds on the maternal plant, is observed in nature and provides ecological advantages in certain wild species, such as mangroves. However, precocious seed germination in agricultural species, such as preharvest sprouting (PHS) in cereals, is a serious issue for food security. PHS reduces grain quality and causes economical losses to farmers. PHS can be prevented by translating the basic knowledge of hormone biology in seeds into technologies. Biosynthesis of abscisic acid (ABA), which is an essential hormone for seed dormancy, can be engineered to enhance dormancy and prevent PHS. Enhancing nine-cis-epoxycarotenoid dioxygenase (NCED), a rate-limiting enzyme of ABA biosynthesis, through a chemically induced gene expression system, has successfully been used to suppress germination of Arabidopsis seeds. The more advanced system NCED positive-feedback system, which amplifies ABA biosynthesis in a seed-specific manner without chemical induction, has also been developed. The proofs of concept established in the model species are now ready to be applied to crops. A potential problem is recovery of germination from hyperdormant crop grains. Hyperdormancy induced by the NCED systems can be reversed by inducing counteracting genes, such as NCED RNA interference or gibberellin (GA) biosynthesis genes. Alternatively, seed sensitivity to ABA can be modified to rescue germination using the knowledge of chemical biology. ABA antagonists, which were developed recently, have great potential to recover germination from the hyperdormant seeds. Combination of the dormancy-imposing and -releasing approaches will establish a comprehensive technology for PHS prevention and germination recovery.
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18
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Vaseghi HR, Yin C, Zhou Y, Wang L, Liu J, Qian L. Generation of an inducible fibroblast cell line for studying direct cardiac reprogramming. Genesis 2016; 54:398-406. [PMID: 27194122 DOI: 10.1002/dvg.22947] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 01/01/2023]
Abstract
Direct reprogramming of fibroblasts into induced cardiomyocytes (iCMs) through forced expression of cardiac-lineage specific transcription factors holds promise as an alternative strategy for cardiac regeneration. To facilitate research in iCM reprogramming, we generated a suite of new tools. We developed a transformed cell line derived from mouse embryonic fibroblasts (MEF). This fibroblast cell line (MEF-T) harbors an αMHC-eGFP reporter transgene for rapid detection of newly derived iCMs. The MEF-T cell line is highly proliferative and easily transfected and transduced, making it an ideal tool for transgene expression and genetic manipulation. Additionally, we generated a Tet-On inducible polycistronic iCM reprogramming construct for the temporal regulation of reprogramming factor expression. Furthermore, we introduced this construct into MEF-T and created an inducible reprogrammable fibroblast cell line. These tools will facilitate future research in cell fate reprogramming by enabling the temporal control of reprogramming factor expression as well as high-throughput screening using libraries of small molecules, noncoding RNAs, and siRNAs. genesis 54:398-406, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Haley Ruth Vaseghi
- Department of Pathology and Laboratory Medicine, McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina
| | - Chaoying Yin
- Department of Pathology and Laboratory Medicine, McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina
| | - Yang Zhou
- Department of Pathology and Laboratory Medicine, McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina
| | - Li Wang
- Department of Pathology and Laboratory Medicine, McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina
| | - Jiandong Liu
- Department of Pathology and Laboratory Medicine, McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina
| | - Li Qian
- Department of Pathology and Laboratory Medicine, McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina
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19
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Christel CJ, Schmied P, Jagusch V, Schrödel S, Thirion C, Schmitt K, Salomon M. Versatile Viral Vector Strategies for Postscreening Target Validation and RNAi ON-Target Control. ACTA ACUST UNITED AC 2015; 20:976-84. [PMID: 25873558 DOI: 10.1177/1087057115581803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 03/24/2015] [Indexed: 12/11/2022]
Abstract
Our approach aims to optimize postscreening target validation strategies using viral vector-driven RNA interference (RNAi) cell models. The RNAiONE validation platform is an array of plasmid-based expression vectors that each drives tandem expression of the gene of interest (GOI) with one small hairpin RNA (shRNA) from a set of computed candidate sequences. The best-performing shRNA (>85% silencing efficiency) is then integrated in an inducible, all-in-one lentiviral vector to transduce pharmacologically relevant cell types that endogenously express the GOI. VariCHECK is used subsequently to combine the inducible knockdown with an equally inducible rescue of the GOI for ON-target phenotype verification. The complete RNAiONE-VariCHECK system relies on three key elements to ensure high predictability: (1) maximized silencing efficiencies by a focused shRNA validation process, (2) homogeneity of the RNAi cell pools by application of sophisticated viral vector technologies, and (3) exploiting the advantages of inducible expression systems. By using a reversible expression system, our strategy adds critical information to hot candidates from RNAi screens and avoids potential side effects that may be caused by other, irreversible genomic manipulation methods such as transcription activator-like effector nucleases (TALEN) or clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas). This approach will add credibility to top-hit screening candidates and protect researchers from costly misinterpretations early in the preclinical drug development process.
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20
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Abstract
The marine bacterium Vibrio fischeri serves as a model organism for a variety of natural phenomena, including symbiotic host colonization. The ease with which the V. fischeri genome can be manipulated contributes greatly to our ability to identify the factors involved in these phenomena. Here, we have adapted genetic tools for use in V. fischeri to promote our ability to conditionally control the expression of genes of interest. Specifically, we modified the commonly used mini-Tn5 transposon to contain an outward-facing, LacI-repressible/IPTG-inducible promoter, and inserted the lacI gene into the V. fischeri chromosome. Used together, these tools permit the identification and induction of genes that control specific phenotypes. To validate this approach, we identified IPTG-controllable motility mutants. We anticipate that the ability to randomly insert an inducible promoter into the genome of V. fischeri will advance our understanding of various aspects of the physiology of this microbe.
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Affiliation(s)
- Jakob M Ondrey
- Department of Microbiology and Immunology, Health Sciences Division, Loyola University Chicago, 2160 S. First Avenue Building 105 Room 3936, Maywood, IL 60153, USA
| | - Karen L Visick
- Department of Microbiology and Immunology, Health Sciences Division, Loyola University Chicago, 2160 S. First Avenue Building 105 Room 3936, Maywood, IL 60153, USA
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21
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Abstract
The construction of increasingly sophisticated synthetic biological circuits is dependent on the development of extensible tools capable of providing specific control of gene expression in eukaryotic cells. Here, we describe a new class of synthetic transcription factors that activate gene expression in response to extracellular chemical stimuli. These inducible activators consist of customizable transcription activator-like effector (TALE) proteins combined with steroid hormone receptor ligand-binding domains. We demonstrate that these ligand-responsive TALE transcription factors allow for tunable and conditional control of gene activation and can be used to regulate the expression of endogenous genes in human cells. Since TALEs can be designed to recognize any contiguous DNA sequence, the conditional gene regulatory system described herein will enable the design of advanced synthetic gene networks.
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Affiliation(s)
- Andrew C. Mercer
- The Skaggs Institute for
Chemical Biology and the Departments of Chemistry and Cell and Molecular
Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Thomas Gaj
- The Skaggs Institute for
Chemical Biology and the Departments of Chemistry and Cell and Molecular
Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Shannon J. Sirk
- The Skaggs Institute for
Chemical Biology and the Departments of Chemistry and Cell and Molecular
Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Brian M. Lamb
- The Skaggs Institute for
Chemical Biology and the Departments of Chemistry and Cell and Molecular
Biology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Carlos F. Barbas
- The Skaggs Institute for
Chemical Biology and the Departments of Chemistry and Cell and Molecular
Biology, The Scripps Research Institute, La Jolla, California 92037, United States
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22
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Abstract
Since the success of homologous recombination in altering mouse genome and the discovery of Cre-loxP system, the combination of these two breakthroughs has created important applications for studying the immune system in the mouse. Here, we briefly summarize the general principles of this technology and its applications in studying immune cell development and responses; such implications include conditional gene knockout and inducible and/or tissue-specific gene over-expression, as well as lineage fate mapping. We then discuss the pros and cons of a few commonly used Cre-expressing mouse lines for studying lymphocyte development and functions. We also raise several general issues, such as efficiency of gene deletion, leaky activity of Cre, and Cre toxicity, all of which may have profound impacts on data interpretation. Finally, we selectively list some useful links to the Web sites as valuable mouse resources.
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Affiliation(s)
- Suveena Sharma
- Molecular and Cellular Immunoregulation Unit, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Jinfang Zhu
- Molecular and Cellular Immunoregulation Unit, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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23
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Cao J, Arha M, Sudrik C, Schaffer DV, Kane RS. Bidirectional regulation of mRNA translation in mammalian cells by using PUF domains. Angew Chem Int Ed Engl 2014; 53:4900-4. [PMID: 24677733 DOI: 10.1002/anie.201402095] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Indexed: 12/12/2022]
Abstract
The regulation of gene expression is crucial in diverse areas of biological science, engineering, and medicine. A genetically encoded system based on the RNA binding domain of the Pumilio and FBF (PUF) proteins was developed for the bidirectional regulation (i.e., either upregulation or downregulation) of the translation of a target mRNA. PUF domains serve as designable scaffolds for the recognition of specific RNA elements and the specificity can be easily altered to target any 8-nucleotide RNA sequence. The expression of a reporter could be varied by over 17-fold when using PUF-based activators and repressors. The specificity of the method was established by using wild-type and mutant PUF domains. Furthermore, this method could be used to activate the translation of target mRNA downstream of PUF binding sites in a light-dependent manner. Such specific bidirectional control of mRNA translation could be particularly useful in the fields of synthetic biology, developmental biology, and metabolic engineering.
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Affiliation(s)
- Jicong Cao
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180 (USA)
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24
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Guo J, Wei J, Xu J, Sun MX. Inducible knock-down of GNOM during root formation reveals tissue-specific response to auxin transport and its modulation of local auxin biosynthesis. J Exp Bot 2014; 65:1165-79. [PMID: 24453227 PMCID: PMC3935571 DOI: 10.1093/jxb/ert475] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In plants, active transport of auxin plays an essential role in root development. Localization of the PIN1 auxin transporters to the basal membrane of cells directs auxin flow and depends on the trafficking mediator GNOM. GNOM-dependent auxin transport is vital for root development and thus offers a useful tool for the investigation of a possible tissue-specific response to dynamic auxin transport. To avoid pleiotropic effects, DEX-inducible expression of GNOM antisense RNA was used to disrupt GNOM expression transiently or persistently during embryonic root development. It was found that the elongation zone and the pericycle layer are the most sensitive to GNOM-dependent auxin transport variations, which is shown by the phenotypes in cell elongation and the initiation of lateral root primordia, respectively. This suggests that auxin dynamics is critical to cell differentiation and cell fate transition, but not to cell division. The results also reveal that GNOM-dependent auxin transport could affect local auxin biosynthesis. This suggests that local auxin biosynthesis may also contribute to the establishment of GNOM-dependent auxin gradients in specific tissues, and that auxin transport and local auxin biosynthesis may function together in the regulatory network for initiation and development of lateral root primordia. Thus, the data reveal a tissue-specific response to auxin transport and modulation of local auxin biosynthesis by auxin transport.
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Affiliation(s)
- Jingzhe Guo
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Jun Wei
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Jian Xu
- Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, Science Drive 4, Singapore117543
| | - Meng-Xiang Sun
- Department of Cell and Developmental Biology, College of Life Science and State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
- * To whom correspondence should be addressed. E-mail:
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25
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Schlücking K, Edel KH, Köster P, Drerup MM, Eckert C, Steinhorst L, Waadt R, Batistic O, Kudla J. A new β-estradiol-inducible vector set that facilitates easy construction and efficient expression of transgenes reveals CBL3-dependent cytoplasm to tonoplast translocation of CIPK5. Mol Plant 2013; 6:1814-29. [PMID: 23713076 DOI: 10.1093/mp/sst065] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Transient and stable expression of transgenes is central to many investigations in plant biology research. Chemical regulation of expression can circumvent problems of plant lethality caused by constitutive overexpression or allow inducible knock (out/down) approaches. Several chemically inducible or repressible systems have been described and successfully applied. However, cloning and application-specific modification of most available inducible expression systems have been limited and remained complicated due to restricted cloning options. Here we describe a new set of 57 vectors that enable transgene expression in transiently or stably transformed cells. All vectors harbor a synthetically optimized XVE expression cassette, allowing β-estradiol mediated protein expression. Plasmids are equipped with the reporter genes GUS, GFP, mCherry, or with HA and StrepII epitope tags and harbor an optimized multiple cloning site for flexible and simple cloning strategies. Moreover, the vector design allows simple substitution of the driving promoter to achieve tissue-specificity or to modulate expression ranges of inducible transgene expression. We report details of the kinetics and dose-dependence of expression induction in Arabidopsis leaf mesophyll protoplasts, transiently transformed Nicotiana benthamiana leaves, and stably transformed Arabidopsis plants. Using these vectors, we investigated the influence of CBL (Calcineurin B-like) protein expression on the subcellular localization of CIPKs (Calcineurin B-like interacting protein kinases). These analyses uncovered that induced co-expression of CBL3 is fully sufficient for dynamic translocation of CIPK5 from the cytoplasm to the tonoplast. Thus, the vector system presented here facilitates a broad range of research applications.
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Affiliation(s)
- Kathrin Schlücking
- Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
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26
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Xiong TC, Hann CM, Chambers JP, Surget M, Ng CKY. An inducible, modular system for spatio-temporal control of gene expression in stomatal guard cells. J Exp Bot 2009; 60:4129-36. [PMID: 19700494 PMCID: PMC2755031 DOI: 10.1093/jxb/erp246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Stomata, flanked by pairs of guard cells, are small pores on the leaf surfaces of plants and they function to control gas exchange between plants and the atmosphere. Stomata will open when water is available to allow for the uptake of carbon dioxide for photosynthesis. During periods of drought, stomata will close to reduce desiccation stress. As such, optimal functioning of stomata will impact on water use efficiency by plants. The development of an inducible, modular system for robust and targeted gene expression in stomatal guard cells is reported here. It is shown that application of ethanol vapour to activate the gene expression system did not affect the ability of stomata to respond to ABA in bioassays to determine the promotion of stomatal closure and the inhibition of stomatal opening. The system that has been developed allows for robust spatio-temporal control of gene expression in all cells of the stomatal lineage, thereby enabling molecular engineering of stomatal function as well as studies on stomatal development.
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Affiliation(s)
- Tou Cheu Xiong
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Cliona M. Hann
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - John P. Chambers
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Marie Surget
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Carl K.-Y. Ng
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland
- To whom correspondence should be addressed: E-mail:
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27
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Abstract
Genomic research has made a large number of sequences of novel genes or expressed sequence tags available. To investigate functions of these genes, a system for conditional control of gene expression would be a useful tool. Inducible transgene expression that uses green fluorescent protein gene (gfp) as a reporter gene has been investigated in transgenic cell lines of cotton (COT; Gossypium hirsutum L.), Fraser fir [FRA; Abies fraseri (Pursh) Poir], Nordmann fir (NOR; Abies nordmanniana Lk.), and rice (RIC; Oryza sativa L. cv. Radon). Transgenic cell lines were used to test the function of the chemical inducer dexamethasone. Inducible transgene expression was observed with fluorescence and confocal microscopy, and was confirmed by northern blot analyses. Dexamethasone at 5 mg/L induced gfp expression to the nearly highest level 48 h after treatment in COT, FRA, NOR, and RIC. Dexamethasone at 10 mg/L inhibited the growth of transgenic cells in FRA and NOR, but not COT and RIC. These results demonstrated that concentrations of inducer for optimum inducible gene expression system varied among transgenic cell lines. The inducible gene expression system described here was very effective and could be valuable in evaluating the function of novel gene.
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Affiliation(s)
- Wei Tang
- Department of Biology, Howell Science Complex, East Carolina University, Greenville, NC 27858-4353, USA.
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28
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Massie B, Mosser DD, Koutroumanis M, Vitté-Mony I, Lamoureux L, Couture F, Paquet L, Guilbault C, Dionne J, Chahla D, Jolicoeur P, Langelier Y. New adenovirus vectors for protein production and gene transfer. Cytotechnology 1998; 28:53-64. [PMID: 19003407 PMCID: PMC3449830 DOI: 10.1023/a:1008013211222] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Based on two new adenovirus expression cassettes, we have constructed a series of Ad transfer vectors for the overexpression of one or two genes either in a dicistronic configuration or with separate expression cassettes. Inclusion of the green or blue fluorescent protein in the vectors accelerates the generation of adenovirus recombinants and facilitates the functional characterization of genes both in vitro and in vivo by allowing easy quantification of gene transfer and expression. With our optimized tetracycline-regulated promoter (TR5) we have generated recombinant adenoviruses expressing proteins, that are either cytotoxic or which interfere with adenovirus replication, at levels of 10-15% of total cell protein. Proteins that are not cytotoxic can be produced at levels greater than 20% of total cell protein. As well, these levels of protein production can be achieved with or without adenovirus replication. This yield is similar to what can be obtained with our optimized human cytomegalovirus-immediate early promoter-enhancer (CMV5) for constitutive protein expression in non-complementing cell lines. Using the green fluorescent protein as a reporter, we have shown that a pAdCMV5-derived adenovirus vector expresses about 6-fold more protein in complementing 293 cells and about 12-fold more in non- complementing HeLa cells than an adenovirus vector containing the standard cytomegalovirus promoter. Moreover, a red-shifted variant of green fluorescent protein incorporated in one series of vectors was 12-fold more fluorescent than the S65T mutant, making the detection of the reporter protein possible at much lower levels of expression.
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Affiliation(s)
- B Massie
- Institut de Recherches en Biotechnologie, 6100 Royalmount Avenue, Montréal, Québec, H4P 2R2, Canada,
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