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Qin H, Anderson D, Zou Z, Higashi D, Borland C, Kreth J, Merritt J. Mass spectrometry and split luciferase complementation assays reveal the MecA protein interactome of Streptococcus mutans. Microbiol Spectr 2024; 12:e0369123. [PMID: 38230956 PMCID: PMC10845952 DOI: 10.1128/spectrum.03691-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/11/2023] [Indexed: 01/18/2024] Open
Abstract
MecA is a highly conserved adaptor protein encoded by prokaryotes from the Bacillota phylum. MecA mutants exhibit similar pleiotropic defects in a variety of organisms, although most of these phenotypes currently lack a mechanistic basis. MecA mediates ClpCP-dependent proteolysis of its substrates, but only several such substrates have been reported in the literature and there are suggestions that proteolysis-independent regulatory mechanisms may also exist. Here, we provide the first comprehensive characterization of the MecA interactome and further assess its regulatory role in Clp-dependent proteolysis. Untargeted coimmunoprecipitation assays coupled with mass spectrometry revealed that the MecA ortholog from the oral pathobiont Streptococcus mutans likely serves as a major protein interaction network hub by potentially complexing with >100 distinct protein substrates, most of which function in highly conserved metabolic pathways. The interactome results were independently verified using a newly developed prokaryotic split luciferase complementation assay (SLCA) to detect MecA protein-protein interactions in vivo. In addition, we further develop a new application of SLCA to support in vivo measurements of MecA relative protein binding affinities. SLCA results were independently verified using targeted coimmunoprecipitation assays, suggesting the general utility of this approach for prokaryotic protein-protein interaction studies. Our results indicate that MecA indeed regulates its interactome through both Clp-dependent proteolysis as well as through an as-yet undefined proteolysis-independent mechanism that may affect more than half of its protein interactome. This suggests a significant aspect of the MecA regulatory function still has yet to be discovered.IMPORTANCEDespite multiple decades of study, the regulatory mechanism and function of MecA have remained largely a mystery. The current study provides the first detailed roadmap to investigate these functions in other medically significant bacteria. Furthermore, this study developed new genetic approaches to assay prokaryotic protein-protein interactions via the split luciferase complementation assay (SLCA). SLCA technology is commonly employed in eukaryotic genetic research but has not yet been established for studies of bacterial protein-protein interactions. The SLCA protein binding affinity assay described here is a new technological advance exclusive to the current study and has not been reported elsewhere.
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Affiliation(s)
- Hua Qin
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
| | - David Anderson
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
| | - Zhengzhong Zou
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
| | - Dustin Higashi
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
| | - Christina Borland
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
| | - Jens Kreth
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - Justin Merritt
- Division of Biomaterial and Biomedical Sciences, Oregon Health & Science University, Portland, Oregon, USA
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
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2
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Xie WJ, Liu D, Wang X, Zhang A, Wei Q, Nandi A, Dong S, Warshel A. Enhancing luciferase activity and stability through generative modeling of natural enzyme sequences. Proc Natl Acad Sci U S A 2023; 120:e2312848120. [PMID: 37983512 PMCID: PMC10691223 DOI: 10.1073/pnas.2312848120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/09/2023] [Indexed: 11/22/2023] Open
Abstract
The availability of natural protein sequences synergized with generative AI provides new paradigms to engineer enzymes. Although active enzyme variants with numerous mutations have been designed using generative models, their performance often falls short of their wild type counterparts. Additionally, in practical applications, choosing fewer mutations that can rival the efficacy of extensive sequence alterations is usually more advantageous. Pinpointing beneficial single mutations continues to be a formidable task. In this study, using the generative maximum entropy model to analyze Renilla luciferase (RLuc) homologs, and in conjunction with biochemistry experiments, we demonstrated that natural evolutionary information could be used to predictively improve enzyme activity and stability by engineering the active center and protein scaffold, respectively. The success rate to improve either luciferase activity or stability of designed single mutants is ~50%. This finding highlights nature's ingenious approach to evolving proficient enzymes, wherein diverse evolutionary pressures are preferentially applied to distinct regions of the enzyme, ultimately culminating in an overall high performance. We also reveal an evolutionary preference in RLuc toward emitting blue light that holds advantages in terms of water penetration compared to other light spectra. Taken together, our approach facilitates navigation through enzyme sequence space and offers effective strategies for computer-aided rational enzyme engineering.
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Affiliation(s)
- Wen Jun Xie
- Department of Chemistry, University of Southern California, Los Angeles, CA90089
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, Genetics Institute, University of Florida, Gainesville, FL32610
| | - Dangliang Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, School of Pharmaceutical Sciences, Peking University, Beijing100191, China
| | - Xiaoya Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, School of Pharmaceutical Sciences, Peking University, Beijing100191, China
| | - Aoxuan Zhang
- Department of Chemistry, University of Southern California, Los Angeles, CA90089
| | - Qijia Wei
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, School of Pharmaceutical Sciences, Peking University, Beijing100191, China
| | - Ashim Nandi
- Department of Chemistry, University of Southern California, Los Angeles, CA90089
| | - Suwei Dong
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, School of Pharmaceutical Sciences, Peking University, Beijing100191, China
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, Los Angeles, CA90089
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3
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Xie WJ, Liu D, Wang X, Zhang A, Wei Q, Nandi A, Dong S, Warshel A. Enhancing Luciferase Activity and Stability through Generative Modeling of Natural Enzyme Sequences. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.18.558367. [PMID: 37786693 PMCID: PMC10541610 DOI: 10.1101/2023.09.18.558367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
The availability of natural protein sequences synergized with generative artificial intelligence (AI) provides new paradigms to create enzymes. Although active enzyme variants with numerous mutations have been produced using generative models, their performance often falls short compared to their wild-type counterparts. Additionally, in practical applications, choosing fewer mutations that can rival the efficacy of extensive sequence alterations is usually more advantageous. Pinpointing beneficial single mutations continues to be a formidable task. In this study, using the generative maximum entropy model to analyze Renilla luciferase homologs, and in conjunction with biochemistry experiments, we demonstrated that natural evolutionary information could be used to predictively improve enzyme activity and stability by engineering the active center and protein scaffold, respectively. The success rate of designed single mutants is ~50% to improve either luciferase activity or stability. These finding highlights nature's ingenious approach to evolving proficient enzymes, wherein diverse evolutionary pressures are preferentially applied to distinct regions of the enzyme, ultimately culminating in an overall high performance. We also reveal an evolutionary preference in Renilla luciferase towards emitting blue light that holds advantages in terms of water penetration compared to other light spectrum. Taken together, our approach facilitates navigation through enzyme sequence space and offers effective strategies for computer-aided rational enzyme engineering.
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Affiliation(s)
- Wen Jun Xie
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
- Departmet of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Dangliang Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, and School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Xiaoya Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, and School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Aoxuan Zhang
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Qijia Wei
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, and School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Ashim Nandi
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Suwei Dong
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, and School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Arieh Warshel
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
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4
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Lu Q, Grotzke JE, Cresswell P. A novel probe to assess cytosolic entry of exogenous proteins. Nat Commun 2018; 9:3104. [PMID: 30082832 PMCID: PMC6079096 DOI: 10.1038/s41467-018-05556-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 07/06/2018] [Indexed: 01/08/2023] Open
Abstract
Dendritic cells use a specialized pathway called cross-presentation to activate CD8+ T cells by presenting peptides from exogenous protein antigens on major histocompatibility complex class I molecules. Considerable evidence suggests that internalized antigens cross endocytic membranes to access cytosolic proteasomes for processing. The mechanism of protein dislocation represents a major unsolved problem. Here we describe the development of a sensitive reporter substrate, an N-glycosylated variant of Renilla luciferase fused to the Fc region of human IgG1. The luciferase variant is designed to be enzymatically inactive when glycosylated, but active after the asparagine to aspartic acid conversion that occurs upon deglycosylation by the cytosolic enzyme N-glycanase-1. The generation of cytosolic luminescence depends on internalization, deglycosylation, the cytosolic AAA-ATPase VCP/p97, and the cytosolic chaperone HSP90. By incorporating a T cell epitope into the fusion protein, we demonstrate that antigen dislocation into the cytosol is the rate limiting step in cross-presentation. The mechanism of protein dislocation into the cytosol during antigen cross-presentation is poorly understood. Here the authors engineer a dislocation reporter fusing a glycosylated luciferase variant to the Fc region of IgG1, and find that dislocation is the rate limiting step in cross-presentation.
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Affiliation(s)
- Qiao Lu
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Jeff E Grotzke
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Peter Cresswell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, 06520, USA.
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5
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Ishibashi M, Kawanabe R, Amaba N, Arai S, Laksmi FA, Komori K, Tokunaga M. Expression and characterization of the Renilla luciferase with the cumulative mutation. Protein Expr Purif 2017; 145:39-44. [PMID: 29288731 DOI: 10.1016/j.pep.2017.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/23/2017] [Accepted: 12/23/2017] [Indexed: 10/18/2022]
Abstract
Luciferase from Renilla reniformis (RLuc) is a good research tool as a reporter protein and bioimaging probes, yielding blue light using the substrate coelenterazine. However, the applications are limited since RLuc is unstable under various conditions. Therefore, an attempt was made to increase RLuc thermostability. In this study, 5 mutations reported previously [1] and one mutation obtained using site-directed mutagenesis were combined. As a result of this combination, the thermostability effect increased, with the mutant showing approximately 10 °C higher stability. Furthermore, the mutant simultaneously improved a tolerance for protease digestion, e.g. trypsin and proteinase K, and for organic solvent. Residual activity of the mutant after treatment with 10% 2-propanol, 10% DMF and 20% DMSO at 35 °C for 1 h was 29.4, 24.8 and 91.3%, respectively, whereas that of the wild type was 0.4, 0.1 and 24.3%, respectively.
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Affiliation(s)
- Matsujiro Ishibashi
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
| | - Ryo Kawanabe
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Norie Amaba
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Shigeki Arai
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Fina Amreta Laksmi
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Kenta Komori
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Masao Tokunaga
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
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6
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Delroisse J, Ullrich-Lüter E, Blaue S, Ortega-Martinez O, Eeckhaut I, Flammang P, Mallefet J. A puzzling homology: a brittle star using a putative cnidarian-type luciferase for bioluminescence. Open Biol 2017; 7:rsob.160300. [PMID: 28381628 PMCID: PMC5413902 DOI: 10.1098/rsob.160300] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 03/06/2017] [Indexed: 01/31/2023] Open
Abstract
Bioluminescence relies on the oxidation of a luciferin substrate catalysed by a luciferase enzyme. Luciferins and luciferases are generic terms used to describe a large variety of substrates and enzymes. Whereas luciferins can be shared by phylogenetically distant organisms which feed on organisms producing them, luciferases have been thought to be lineage-specific enzymes. Numerous light emission systems would then have co-emerged independently along the tree of life resulting in a plethora of non-homologous luciferases. Here, we identify for the first time a candidate luciferase of a luminous echinoderm, the ophiuroid Amphiura filiformis Phylogenomic analyses identified the brittle star predicted luciferase as homologous to the luciferase of the sea pansy Renilla (Cnidaria), contradicting with the traditional viewpoint according to which luciferases would generally be of convergent origins. The similarity between the Renilla and Amphiura luciferases allowed us to detect the latter using anti-Renilla luciferase antibodies. Luciferase expression was specifically localized in the spines which were demonstrated to be the bioluminescent organs in vivo However, enzymes homologous to the Renilla luciferase but unable to trigger light emission were also identified in non-luminous echinoderms and metazoans. Our findings strongly indicate that those enzymes, belonging to the haloalkane dehalogenase family, might then have been convergently co-opted into luciferases in cnidarians and echinoderms. In these two benthic suspension-feeding species, similar ecological pressures would constitute strong selective forces for the functional shift of these enzymes and the emergence of bioluminescence.
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Affiliation(s)
- Jérôme Delroisse
- Research Institute for Biosciences, Biology of Marine Organisms and Biomimetics, University of Mons - UMONS, 23 Place du Parc, 7000 Mons, Belgium
| | - Esther Ullrich-Lüter
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr. 43, 10115 Berlin, Germany
| | - Stefanie Blaue
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr. 43, 10115 Berlin, Germany
| | - Olga Ortega-Martinez
- Department of Marine Science, The Sven Lovén Centre for Marine Sciences - Kristineberg, University of Gothenburg, 45178 Fiskebäckskil, Sweden
| | - Igor Eeckhaut
- Research Institute for Biosciences, Biology of Marine Organisms and Biomimetics, University of Mons - UMONS, 23 Place du Parc, 7000 Mons, Belgium
| | - Patrick Flammang
- Research Institute for Biosciences, Biology of Marine Organisms and Biomimetics, University of Mons - UMONS, 23 Place du Parc, 7000 Mons, Belgium
| | - Jérôme Mallefet
- Marine Biology Laboratory, Université Catholique de Louvain, ELI, 3 Place Croix du Sud L7.04.06, 1348 Louvain-La-Neuve, Belgium
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7
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Molecular basis of thermostability enhancement of Renilla luciferase at higher temperatures by insertion of a disulfide bridge into the structure. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:252-259. [DOI: 10.1016/j.bbapap.2016.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 11/20/2022]
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8
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Rahnama S, Saffar B, Kahrani ZF, Nazari M, Emamzadeh R. Super RLuc8: A novel engineered Renilla luciferase with a red-shifted spectrum and stable light emission. Enzyme Microb Technol 2016; 96:60-66. [PMID: 27871386 DOI: 10.1016/j.enzmictec.2016.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/18/2016] [Accepted: 09/19/2016] [Indexed: 11/17/2022]
Abstract
Renilla luciferase is a bioluminescent enzyme which is broadly used as a reporter protein in molecular biosensors. In this study, a novel luciferase with desired light emission wavelength and thermostability is reported. The results indicated that the new luciferase, namely super RLuc8, had a red-shifted spectrum and showed stable light emission. Super RLuc8 showed a 10-fold (p-value=0.0084) increase in the thermostability at 37°C after 20min incubation, in comparison to the native enzyme. The optimum temperature of the mutant increased from 30 to 37°C. Molecular dynamics simulation analysis indicated that the increased thermostability was most probably caused by a better structural compactness and more local rigidity in the regions out of the emitter site.
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Affiliation(s)
- Somaieh Rahnama
- Department of Biology, Nourdanesh Institute of Higher Education, Meymeh, Iran
| | - Behnaz Saffar
- Department of Genetics, Shahrekord University, Shahrekord, Iran
| | | | - Mahboobeh Nazari
- Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
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9
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Novel functional Renilla luciferase mutant provides long-term serum stability and high luminescence activity. Protein Expr Purif 2013; 91:215-20. [DOI: 10.1016/j.pep.2013.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/15/2013] [Accepted: 08/02/2013] [Indexed: 11/22/2022]
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10
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Xu Y, Kreth J. Role of LytF and AtlS in eDNA release by Streptococcus gordonii. PLoS One 2013; 8:e62339. [PMID: 23638042 PMCID: PMC3634736 DOI: 10.1371/journal.pone.0062339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/20/2013] [Indexed: 02/07/2023] Open
Abstract
Extracellular DNA (eDNA) is an important component of the biofilm matrix produced by many bacteria. In general, the release of eDNA is associated with the activity of muralytic enzymes leading to obvious cell lysis. In the Gram-positive oral commensal Streptococcus gordonii, eDNA release is dependent on pyruvate oxidase generated hydrogen peroxide (H2O2). Addition of H2O2 to cells grown under conditions non-permissive for H2O2 production causes eDNA release. Furthermore, eDNA release is maximal under aerobic growth conditions known to induce pyruvate oxidase gene expression and H2O2 production. Obvious cell lysis, however, does not occur. Two enzymes have been recently associated with eDNA release in S. gordonii. The autolysin AtlS and the competence regulated murein hydrolase LytF. In the present report, we investigated the role of both proteins in the H2O2 dependent eDNA release process. Single and double mutants in the respective genes for LytF and AtlS released less eDNA under normal growth conditions, but the AtlS mutant was still inducible for eDNA release by external H2O2. Moreover, we showed that the AtlS mutation interfered with the ability of S. gordonii to produce eDNA release inducing amounts of H2O2. Our data support a role of LytF in the H2O2 eDNA dependent release of S. gordonii as part of the competence stress pathway responding to oxidative stress.
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Affiliation(s)
- Yifan Xu
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Surgical Oncology, The First Hospital of China Medical University, Shenyang, PR China
| | - Jens Kreth
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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11
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Tomoyasu T, Tabata A, Ishikawa Y, Whiley RA, Nagamune H. Small heat shock protein AgsA: an effective stabilizer of enzyme activities. J Biosci Bioeng 2012; 115:15-9. [PMID: 22929984 DOI: 10.1016/j.jbiosc.2012.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/26/2012] [Accepted: 08/06/2012] [Indexed: 11/16/2022]
Abstract
A small heat shock protein, AgsA, possesses chaperone activity that can reduce the amount of heat-aggregated protein in vivo, and suppress the aggregation of chemical- and heat-denatured proteins in vitro. Therefore, we examined the ability of AgsA to stabilize the activity of several enzymes by using this chaperone activity. We observed that AgsA can stabilize the enzymatic activities of Renilla (Renilla reniformis) luciferase, firefly (Photinus pyralis) luciferase, and β-galactosidase, and showed comparable or greater stabilization of these enzymes than bovine serum albumin (BSA), a well-known stabilizer of enzyme activities. In particular, AgsA revealed better stabilization of Renilla luciferase and β-galactosidase than BSA under disulfide bond-reducing conditions with dithiothreitol. In addition, AgsA also increased the enzymatic performance of β-galactosidase and various restriction enzymes to a comparable or greater extent than BSA. These data indicate that AgsA may be useful as a general stabilizer of enzyme activities.
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Affiliation(s)
- Toshifumi Tomoyasu
- Department of Biological Science and Technology, Institute of Technology and Science, The University of Tokushima Graduate School, Minami-Josanjima-cho, Tokushima 770-8506, Japan.
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12
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Kobatake E, Kosaku C, Hanzawa S, Mie M. Construction of affinity changeable antibody in response to Ca2+. Biotechnol Lett 2012; 34:1019-23. [PMID: 22350334 DOI: 10.1007/s10529-012-0881-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 02/10/2012] [Indexed: 10/28/2022]
Abstract
Immunoaffinity chromatography is a powerful method for purification of proteins because of the high selectivity and avidity of antibodies. Due to the strength of antigen-antibody binding, however, elution of proteins bound to antibodies that are covalently immobilized on the column is performed by temporary denaturation of the antibody. Therefore, the development of milder elution conditions could improve the recovery of the antibodies and prolong the life of the immunoaffinity column. We describe the design and construction of an antibody that changes its affinity in response to external stimuli. The heavy chain and light chain of a single chain Fv of the D1.3 antibody against hen egg-white lysozyme (HEL) were fused at the N- and C-termini, respectively, of the calmodulin-M13 fusion protein. The affinity of this fusion protein for HEL could be modulated by changing the Ca(2+) concentration.
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Affiliation(s)
- Eiry Kobatake
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan.
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13
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Zhang L, Moo-Young M, Chou CP. Molecular manipulation associated with disulfide bond formation to enhance the stability of recombinant therapeutic protein. Protein Expr Purif 2011; 75:28-39. [PMID: 20719248 DOI: 10.1016/j.pep.2010.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 08/10/2010] [Accepted: 08/11/2010] [Indexed: 11/17/2022]
Abstract
Cys²⁷ in the extracellular domain of human CD83 (hCD83ext), a potential therapeutic protein, was identified as a target for molecular manipulation. Two Escherichia coli strains of BL21(DE3) and Origami B(DE3), respectively, with a reducing and an oxidative cytoplasm were used as the expression host to produce the Cys²⁷ mutants. It was observed that Cys²⁷ was involved in the in vivo formation of intramolecular disulfide bonds when hCD83ext was expressed in Origami B(DE3). The Origami-derived protein products had a higher tendency than the BL21-derived counterparts for multimerization via the in vitro formation of intermolecular disulfide bonds. Various analyses were conducted to identify the structural differences among these mutant variants. Most importantly, molecular stability was enhanced by the Cys²⁷ mutations since the Cys²⁷ mutants derived from either BL21 or Origami were much less susceptible to degradation compared to wild-type hCD83ext. This study highlights the implications of aberrant disulfide bond formation on the production of therapeutic proteins.
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Affiliation(s)
- Lin Zhang
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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14
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Ching KH, Burbelo PD, Kimball RM, Clawson LL, Corse AM, Iadarola MJ. Recombinant expression of the AChR-alpha1 subunit for the detection of conformation-dependent epitopes in Myasthenia Gravis. Neuromuscul Disord 2010; 21:204-13. [PMID: 21195619 DOI: 10.1016/j.nmd.2010.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 10/15/2010] [Accepted: 12/03/2010] [Indexed: 12/21/2022]
Abstract
Detection of autoantibodies associated with neurological disease typically involves immunoprecipitation of radioactively labeled native proteins. We explored whether single receptor subunits, fused to Renilla luciferase (Ruc), could detect patient autoantibodies in Luciferase Immunoprecipitation Systems. Myasthenia Gravis patient sera were tested for conformational autoantibodies to only the α1-subunit of the nicotinic acetylcholine receptor (AChR). Using a panel of 10 AChR-α1 fragments, AChR-α1-Δ5-Ruc demonstrated the highest immunoreactivity with a conformational-specific antibody and the highest sensitivity in a pilot cohort. Testing a larger cohort with AChR-α1-Δ5-Ruc demonstrated 21% sensitivity and 97% specificity. A point mutation within Ruc increased the diagnostic performance of AChR-α1-Δ5 (32% sensitivity, 97% specificity). The (125)I-α-bungarotoxin multi-subunit AChR assay demonstrated 63% sensitivity and 97% specificity. These findings highlight the difficulty in detecting Myasthenia Gravis conformational epitopes across assay formats and lay the foundation for detecting autoantibodies to defined recombinant chains of the AChR and potentially other neurotransmitter receptors.
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Affiliation(s)
- Kathryn H Ching
- Neurobiology and Pain Therapeutics Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, 49 Convent Drive, Bethesda, MD 20892-4410, United States
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15
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Chen PT, Chiang CJ, Chao YP. Medium optimization and production of secreted Renilla luciferase in Bacillus subtilis by fed-batch fermentation. Biochem Eng J 2010. [DOI: 10.1016/j.bej.2010.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chiang CJ, Chen PT, Chao YP. Secreted production ofRenillaluciferase inBacillus subtilis. Biotechnol Prog 2009; 26:589-94. [DOI: 10.1002/btpr.351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Kaihara A, Umezawa Y, Furukawa T. Bioluminescent indicators for Ca2+ based on split Renilla luciferase complementation in living cells. ANAL SCI 2008; 24:1405-8. [PMID: 18997366 DOI: 10.2116/analsci.24.1405] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Genetically encoded bioluminescent indicators for intracellular Ca2+ are described here with CaM-M13 interaction-induced complementation of split Renilla luciferase. The Ca2+-induced interaction between CaM and M13 leads to complementation of the N- and C-terminal halves of split Renilla luciferase in living cells. This intramolecular interaction results in the spontaneous and simultaneous emission of bioluminescence split Renilla luciferase. This is how intracellular Ca2+ is illuminated with the intramolecular complementation of split Renilla luciferase. The Ca2+-dependent spontaneous and simultaneous emission of bioluminescence promises to reveal Ca2+ dynamics in living cells, and also in vivo using the present indicators.
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Affiliation(s)
- Asami Kaihara
- Department of Bio-Informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Chiyoda, Tokyo 101-0062, Japan.
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18
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Andou T, Endoh T, Mie M, Kobatake E. RNA detection using peptide-inserted Renilla luciferase. Anal Bioanal Chem 2008; 393:661-8. [PMID: 18979090 DOI: 10.1007/s00216-008-2473-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 10/06/2008] [Accepted: 10/09/2008] [Indexed: 11/26/2022]
Abstract
A novel complementation system with short peptide-inserted-Renilla luciferase (PI-Rluc) and split-RNA probes was constructed for noninvasive RNA detection. The RNA binding peptides HIV-1 Rev and BIV Tat were used as inserted peptides. They display induced fit conformational changes upon binding to specific RNAs and trigger complementation or discomplementation of Rluc. Split-RNA probes were designed to reform the peptide binding site upon hybridization with arbitrarily selected target RNA. This set of recombinant protein and split-RNA probes enabled a high degree of sensitivity in RNA detection. In this study, we show that the Rluc system is comparable to Fluc, but that its detection limit for arbitrarily selected RNA (at least 100 pM) exceeds that of Fluc by approximately two orders of magnitude.
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Affiliation(s)
- Takashi Andou
- Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan
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19
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Miller E, Fiete D, Blake NMJ, Beranek M, Oates EL, Mi Y, Roseman DS, Baenziger JU. A necessary and sufficient determinant for protein-selective glycosylation in vivo. J Biol Chem 2007; 283:1985-91. [PMID: 18048353 DOI: 10.1074/jbc.m708160200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A limited number of glycoproteins including luteinizing hormone and carbonic anhydrase-VI (CA6) bear N-linked oligosaccharides that are modified with beta1,4-linked N-acetylgalactosamine (GalNAc). The selective addition of GalNAc to these glycoproteins requires that the beta1,4-N-acetylgalactosaminyltransferase (betaGT) recognize both the oligosaccharide acceptor and a peptide recognition determinant on the substrate glycoprotein. We report here that two recently cloned betaGTs, betaGT3 and betaGT4, that are able to transfer GalNAc to GlcNAc in beta1,4-linkage display the necessary glycoprotein specificity in vivo. Both betaGTs transfer GalNAc to N-linked oligosaccharides on the luteinizing hormone alpha subunit and CA6 but not to those on transferrin (Trf). A single peptide recognition determinant encoded in the carboxyl-terminal 19-amino acid sequence of bovine CA6 mediates transfer of GalNAc to each of its two N-linked oligosaccharides. The addition of this 19-amino acid sequence to the carboxyl terminus of Trf confers full acceptor activity onto Trf for both betaGT3 and betaGT4 in vivo. The complete 19-amino acid sequence is required for optimal GalNAc addition in vivo, indicating that the peptide sequence is both necessary and sufficient for recognition by betaGT3 and betaGT4.
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Affiliation(s)
- Erin Miller
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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20
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Ojogho O, Li A, Zuppan CW, Escher A. Bioluminescent Mammalian Cells Grown in Sponge Matrices to Monitor Immune Rejection. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The growth and bioluminescence of cells seeded in collagen and gelatin sponge matrices were compared in vitro under different conditions, and immune rejection was quantified and visualized directly in situ based on loss of bioluminescence activity. Mammalian cells expressing a Renilla luciferase complementary deoxyribonucleic acid (cDNA) were used to seed collagen and gelatin sponge matrices soaked in either polylysine or gelatin to determine optimal growth conditions in vitro. The sponges were incubated in tissue culture plates for 3 weeks and received 2, 9, or 15 injections of coelenterazine. Measurements of bioluminescence activity indicated that gelatin sponges soaked in gelatin emitted the highest levels of light emission, multiple injections of coelenterazine did not affect light emission significantly, and light emission from live cells grown in sponges could be measured qualitatively but not quantitatively. Histologic analysis of sponge matrices cultured in vitro showed that cells grew best in gelatin matrices. Visualization of subcutaneously implanted sponges in mice showed accelerated loss of light emission in immunocompetent BALB/c mice compared with immunodeficient BALB/c- scid mice, which was associated with increased cell infiltration. Our results indicate that sponge matrices carrying bioluminescent mammalian cells are a valid model system to study immune rejection in situ.
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Affiliation(s)
- Okechukwu Ojogho
- From the Transplantation Institute, Center for Transplant Immunology Research, Department of Biochemistry and Microbiology Department of Pathology, Loma Linda University and Medical Center, Loma Linda, CA
| | - Alice Li
- From the Transplantation Institute, Center for Transplant Immunology Research, Department of Biochemistry and Microbiology Department of Pathology, Loma Linda University and Medical Center, Loma Linda, CA
| | - Craig W. Zuppan
- From the Transplantation Institute, Center for Transplant Immunology Research, Department of Biochemistry and Microbiology Department of Pathology, Loma Linda University and Medical Center, Loma Linda, CA
| | - Alan Escher
- From the Transplantation Institute, Center for Transplant Immunology Research, Department of Biochemistry and Microbiology Department of Pathology, Loma Linda University and Medical Center, Loma Linda, CA
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21
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Pfleger KDG, Eidne KA. Illuminating insights into protein-protein interactions using bioluminescence resonance energy transfer (BRET). Nat Methods 2006; 3:165-74. [PMID: 16489332 DOI: 10.1038/nmeth841] [Citation(s) in RCA: 401] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Bioluminescence resonance energy transfer (BRET) is a straightforward biophysical technique for studying protein-protein interactions. It requires: (1) that proteins of interest and suitable controls be labeled with either a donor or acceptor molecule, (2) placement of these labeled proteins in the desired environment for assessing their potential interaction, and (3) use of suitable detection instrumentation to monitor resultant energy transfer. There are now several possible applications, combinations of donor and acceptor molecules, potential assay environments and detection system perturbations. Therefore, this review aims to demystify and clarify the important aspects of the BRET methodology that should be considered when using this technique.
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Affiliation(s)
- Kevin D G Pfleger
- 7TM Laboratory/Laboratory for Molecular Endocrinology, Western Australian Institute for Medical Research, UWA Centre for Medical Research, University of Western Australia, Nedlands, Perth, Western Australia 6009, Australia.
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22
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Yamagishi K, Enomoto T, Ohmiya Y. Perfusion-culture-based secreted bioluminescence reporter assay in living cells. Anal Biochem 2006; 354:15-21. [PMID: 16713985 DOI: 10.1016/j.ab.2006.03.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 03/08/2006] [Accepted: 03/20/2006] [Indexed: 11/20/2022]
Abstract
Bioluminescence reporter proteins have been widely used in the development of tools for monitoring biological events in living cells. In this study, we describe the development of a reporter system with secreted Cypridina noctiluca luciferase (CLuc) for a pharmacological assay that is based on targeted promoter activity. A model cell line was established with Rat-1 fibroblasts expressing CLuc driven by the promoter of a circadian clock gene, Bmal1. To accurately assay for temporally secreted CLuc activity, a perfusion culture in which the promoter activity was sequentially monitored by the reporter activity in the perfusate was adopted. By pulsing with dexamethasone (DEX), a glucocorticoid (GC) analog, the profile of the reporter activity successfully showed diurnal fluctuation, which is a canonical expression pattern of the Bmal1 gene. Trial studies illustrated that the DEX-pulsed circadian oscillation was reasonably attenuated by RU486, a GC receptor antagonist. Moreover, SP600125, a c-Jun N-terminal kinase inhibitor, caused phase shifting of the rhythmicity. We conclude that the CLuc reporter assay in combination with perfusion culture is a suitable pharmacological tool for drug discovery.
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Affiliation(s)
- Kazutoshi Yamagishi
- Cell Dynamics Research Group, Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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23
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Doyle TC, Nawotka KA, Purchio AF, Akin AR, Francis KP, Contag PR. Expression of firefly luciferase in Candida albicans and its use in the selection of stable transformants. Microb Pathog 2006; 40:69-81. [PMID: 16427765 DOI: 10.1016/j.micpath.2005.11.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 11/03/2005] [Accepted: 11/07/2005] [Indexed: 11/18/2022]
Abstract
The infectious yeast Candida albicans is a model organism for understanding the mechanisms of fungal pathogenicity. We describe the functional expression of the firefly luciferase gene, a reporter commonly used to tag genes in many other cellular systems. Due to a non-standard codon usage by this yeast, the CUG codons were first mutated to UUG to allow functional expression. When integrated into the chromosome of C. albicans with a strong constitutive promoter, cells bioluminesce when provided with luciferin substrate in their media. When fused to the inducible promoter from the HWP1 gene, expression and bioluminescence was only detected in cultures conditioning hyphal growth. We further used the luciferase gene as a selection to isolate transformed cell lines from clinical isolates of C. albicans, using a high-density screening strategy that purifies transformed colonies by virtue of light emission. This strategy requires no drug or auxotrophic selectable marker, and we were thus able to generate stable transformants of clinical isolates that are identical to the parental strain in all aspects tested, other than their bioluminescence. The firefly luciferase gene can, therefore, be used as a sensitive reporter to analyze gene function both in laboratory and clinical isolates of this medically important yeast.
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Affiliation(s)
- Timothy C Doyle
- Xenogen Corporation, 860 Atlantic Avenue, Alameda, CA 94501, USA.
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24
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Ozawa T. Designing split reporter proteins for analytical tools. Anal Chim Acta 2006; 556:58-68. [PMID: 17723331 DOI: 10.1016/j.aca.2005.06.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 06/01/2005] [Accepted: 06/08/2005] [Indexed: 11/25/2022]
Abstract
A current focus of biological research is to quantify and image cellular processes in living cells and animals. To detect such cellular processes, genetically-encoded reporters have been extensively used. The most common reporters include firefly luciferase, renilla luciferase, green fluorescent protein (GFP) and its variants with various spectral properties. This review describes novel design of split-GFP and luciferase reporters based on protein splicing, and highlights some potential applications with the reporters to study protein-protein interactions, protein localization, intracellular protein dynamics, and protein activity in living cells and animals.
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Affiliation(s)
- Takeaki Ozawa
- Department of Molecular Structure, Institute for Molecular Science, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan.
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25
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Ozawa T. Methods of Analysis for Protein Dynamics in Living Cells Based on Protein Splicing. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2005. [DOI: 10.1246/bcsj.78.739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Nieuwenhuijsen BW, Huang Y, Wang Y, Ramirez F, Kalgaonkar G, Young KH. A dual luciferase multiplexed high-throughput screening platform for protein-protein interactions. ACTA ACUST UNITED AC 2004; 8:676-84. [PMID: 14711393 DOI: 10.1177/1087057103258287] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To study the biology of regulators of G-protein signaling (RGS) proteins and to facilitate the identification of small molecule modulators of RGS proteins, the authors recently developed an advanced yeast 2-hybrid (YTH) assay format for GalphaZ and RGS-Z1. Moreover, they describe the development of a multiplexed luciferase-based assay that has been successfully adapted to screen large numbers of small molecule modulators of protein-protein interactions. They generated and evaluated 2 different luciferase reporter gene systems for YTH interactions, a Gal4 responsive firefly luciferase reporter gene and a Gal4 responsive Renilla luciferase reporter gene. Both the firefly and Renilla luciferase reporter genes demonstrated a 40- to 50-fold increase in luminescence in strains expressing interacting YTH fusion proteins versus negative control strains. Because the firefly and Renilla luciferase proteins have different substrate specificity, the assays were multiplexed. The multiplexed luciferase-based YTH platform adds speed, sensitivity, simplicity, quantification, and efficiency to YTH high-throughput applications and therefore greatly facilitates the identification of small molecule modulators of protein-protein interactions as tools or potential leads for drug discovery efforts.
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27
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Sudomoina M, Latypova E, Favorova OO, Golemis EA, Serebriiskii IG. A gene expression system offering multiple levels of regulation: the Dual Drug Control (DDC) system. BMC Biotechnol 2004; 4:9. [PMID: 15117411 PMCID: PMC420247 DOI: 10.1186/1472-6750-4-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2003] [Accepted: 04/29/2004] [Indexed: 12/17/2022] Open
Abstract
Background Whether for cell culture studies of protein function, construction of mouse models to enable in vivo analysis of disease epidemiology, or ultimately gene therapy of human diseases, a critical enabling step is the ability to achieve finely controlled regulation of gene expression. Previous efforts to achieve this goal have explored inducible drug regulation of gene expression, and construction of synthetic promoters based on two-hybrid paradigms, among others. Results In this report, we describe the combination of dimerizer-regulated two-hybrid and tetracycline regulatory elements in an ordered cascade, placing expression of endpoint reporters under the control of two distinct drugs. In this Dual Drug Control (DDC) system, a first plasmid expresses fusion proteins to DBD and AD, which interact only in the presence of a small molecule dimerizer; a second plasmid encodes a cassette transcriptionally responsive to the first DBD, directing expression of the Tet-OFF protein; and a third plasmid encodes a reporter gene transcriptionally responsive to binding by Tet-OFF. We evaluate the dynamic range and specificity of this system in comparison to other available systems. Conclusion This study demonstrates the feasibility of combining two discrete drug-regulated expression systems in a temporally sequential cascade, without loss of dynamic range of signal induction. The efficient layering of control levels allowed by this combination of elements provides the potential for the generation of complex control circuitry that may advance ability to regulate gene expression in vivo.
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Affiliation(s)
- Marina Sudomoina
- Department of Molecular Biology and Biotechnology, Russian State Medical University, Moscow, Russia
| | - Ekaterina Latypova
- Division of Basic Science, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Olga O Favorova
- Department of Molecular Biology and Biotechnology, Russian State Medical University, Moscow, Russia
| | - Erica A Golemis
- Division of Basic Science, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Ilya G Serebriiskii
- Division of Basic Science, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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28
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Kotarsky K, Nilsson NE, Olde B, Owman C. Progress in Methodology Improved Reporter Gene Assays Used to Identify Ligands Acting on Orphan Seven-Transmembrane Receptors. ACTA ACUST UNITED AC 2003; 93:249-58. [PMID: 14675457 DOI: 10.1111/j.1600-0773.2003.pto930601.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Seven-transmembrane G-protein-coupled receptors play a central role in physiology by facilitating cell communication through recognition of a wide range of ligands. Even more important, they represent important drug targets. Unfortunately, for many of these receptors the endogenous ligands, and hence their functions, remain to be identified. These receptors are referred to as "orphan" receptors. A pre-requisite for the identification of ligands activating orphan receptors is powerful assay systems. Until now, reporter gene assays have not been in common use in this process. Here, we summarize our development of improved reporter gene assays. We optimized reporter gene assays in respect of (i) the promoter region of the construct, (ii) the reporter enzyme used, (iii) and the assay procedure. Furthermore, an unique fluorescence-based clone selection step was introduced, allowing rapid selection of the most sensitive reporter cell clones when establishing stable reporter cell lines. Mathematical formulae are provided to enable a simple and reliable comparison between different cell lines, when tested with a compound of interest. The resulting reporter cell lines responded in a very sensitive way to the stimulation of various test receptors. The reporter system was termed HighTRACE (high-throughput reporter assay with clone election). Its high assay quality makes it suitable as a primary screening tool. Ligands for two recently unknown 7TM receptors were identified using the HighTRACE system i.e., two cell surface free fatty acid receptors, GPR40 (FFA1R) and GPR43 (FFA2R). The identification was accomplished using a reverse pharmacology approach.
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Affiliation(s)
- Knut Kotarsky
- Division of Molecular Neurobiology, Department of Physiological Sciences, Wallenberg Neuroscience Center, S-221 84 Lund, Sweden
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29
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Kotarsky K, Antonsson L, Owman C, Olde B. Optimized reporter gene assays based on a synthetic multifunctional promoter and a secreted luciferase. Anal Biochem 2003; 316:208-15. [PMID: 12711342 DOI: 10.1016/s0003-2697(03)00082-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Efficient screening for ligands of seven-transmembrane, G-protein-coupled receptors, whether transfected or endogenously expressed, often involves cell-based reporter assays. Here we describe the development of reporter gene assays in HeLa cells. The reporter construct includes a synthetic multifunctional promoter with several different response motifs (NF-kappaB, STAT, and AP-1) and hence efficiently funnels several signaling pathways. The assay, performed with the resulting reporter cell line HFF11, has an exceptional high Z-factor and a large signal-to-background ratio. To facilitate cell handling during screening, we introduced a secreted Renilla luciferase as a reporter enzyme. HR36 reporter cells, equipped with the construct, were added to ligands present in a multiwell plate and after addition of coelenterazine they produced a luminescence readout. This procedure economizes cell handling and at the same time increases assay quality and sensitivity
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Affiliation(s)
- Knut Kotarsky
- Division of Molecular Neurobiology, Wallenberg Neuroscience Center, Lund University, Sweden.
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30
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Ma Y, Erkner A, Gong R, Yao S, Taipale J, Basler K, Beachy PA. Hedgehog-mediated patterning of the mammalian embryo requires transporter-like function of dispatched. Cell 2002; 111:63-75. [PMID: 12372301 DOI: 10.1016/s0092-8674(02)00977-7] [Citation(s) in RCA: 224] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The dispatched (disp) gene is required for long-range Hedgehog (Hh) signaling in Drosophila. Here, we demonstrate that one of two murine homologs, mDispA, can rescue disp function in Drosophila and is essential for all Hh patterning activities examined in the early mouse embryo. Embryonic fibroblasts lacking mDispA respond normally to exogenously provided Sonic hedgehog (Shh) signal, but are impaired in stimulation of other responding cells when expressing Shh. We have developed a biochemical assay that directly measures the activity of Disp proteins in release of soluble Hh proteins. This activity is disrupted by alteration of residues functionally conserved in Patched and in a related family of bacterial transmembrane transporters, thus suggesting similar mechanisms of action for all of these proteins.
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Affiliation(s)
- Yong Ma
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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31
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Schlatter S, Rimann M, Kelm J, Fussenegger M. SAMY, a novel mammalian reporter gene derived from Bacillus stearothermophilus alpha-amylase. Gene 2002; 282:19-31. [PMID: 11814674 DOI: 10.1016/s0378-1119(01)00824-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Bacillus stearothermophilus alpha-amylase (amyS) is a heat-stable monomeric exoenzyme which catalyses random hydrolysis of 1,4-alpha-glucosidic linkages in polyglucosans. The Bacillus alpha-amylase was engineered for use as an intracellular (AmyS(Delta S)) as well as a secreted reporter protein (SAMY; secreted alpha-amylase) in mammalian cells. The 5' end of amyS containing the prokaryotic secretion signal was either deleted (amyS(Delta S)) or replaced by a murine immunoglobulin secretion signal. SAMY was cloned under control of the cytomegalovirus promoter (P(CMV)) in a mammalian expression vector or the promoter of the human elongation factor 1 alpha (P(EF1 alpha)) in a lentiviral expression context. A variety of mammalian and human cell lines growing as monolayers, in suspension or as three-dimensional spheroids were transfected/transduced with SAMY- or amyS(Delta S)-encoding expression/lentiviral vectors and alpha-amylase activity was measured in cell lysates and culture supernatants. These experiments showed that SAMY and AmyS(Delta S) were either secreted or remained intracellular as highly sensitive reporter enzymes. SAMY expression and detection was fully compatible with established SEAP (human secreted alkaline phosphatase) and u-PA(LMW) (low molecular weight urokinase-type plasminogen activator) reporter systems and could be used to quantify expression of up to three independent genes in one culture supernatant.
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Affiliation(s)
- Stefan Schlatter
- Institute of Biotechnology, Swiss Federal Institute of Technology, ETH Hoenggerberg, CH-8093 Zurich, Switzerland
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32
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Filippova M, Liu J, Escher A. Effects of plasmid DNA injection on cyclophosphamide-accelerated diabetes in NOD mice. DNA Cell Biol 2001; 20:175-81. [PMID: 11313020 DOI: 10.1089/104454901300069022] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Type 1 diabetes results in most cases from the destruction of insulin-secreting beta cells by the immune system. Several immunization methods based on administration of autoantigenic polypeptides such as insulin and glutamic acid decarboxylase (GAD) have been used to prevent autoimmune diabetes in the non-obese diabetic (NOD) mouse. In the work presented here, a gene-based approach was taken for a similar purpose. A plasmid carrying different cDNAs was used to investigate the effects of injecting naked DNA on cyclophosphamide-accelerated diabetes in female NOD mice. Four-week-old animals received intramuscular injections of plasmid DNA encoding either intracellular GAD, a secreted form of GAD, or a secreted form of a soft coral luciferase. Monitoring of glycosuria and hyperglycemia indicated that injection of plasmid DNA encoding secreted GAD and secreted luciferase could prevent and delay diabetes, respectively. In contrast, injection of DNA encoding intracellular GAD did not suppress the disease significantly. Analysis of anti-GAD IgG(1) antibody titers in animal sera indicated that diabetes prevention after injection of GAD-encoding DNA was possibly associated with increased Th2-type activity. These results suggest that cellular localization of GAD is a factor to consider in the design of GAD-based genetic vaccines for the prevention of autoimmune diabetes.
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Affiliation(s)
- M Filippova
- Center for Molecular Biology and Gene Therapy, Loma Linda University, Loma Linda, California 92350, USA
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