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Wright DJ, O'Reilly M, Tisi D. Engineering and purification of a thermostable, high-yield, variant of PfCRT, the Plasmodium falciparum chloroquine resistance transporter. Protein Expr Purif 2017; 141:7-18. [PMID: 28823509 DOI: 10.1016/j.pep.2017.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 06/16/2017] [Accepted: 08/10/2017] [Indexed: 11/30/2022]
Abstract
Historically chloroquine was used to treat the most deadly form of malaria, caused by the parasite Plasmodium falciparum. The selective pressure of chloroquine therapy led to the rapid emergence of chloroquine resistant parasites. Resistance has been attributed to the Plasmodium falciparum Chloroquine Resistance Transporter (PfCRT), an integral membrane protein of unknown structure. A PfCRT structure would provide new insights into how the protein confers chloroquine resistance and thereby also yield novel opportunities for developing anti-malarial therapies. Although PfCRT is an attractive target for characterisation and structure determination, very little work has been published on its expression and purification. Here we present a medium throughput protocol, employing Sf9 insect cells, for testing the expression, stability and purification yield of rationally designed PfCRT mutant constructs and constructs of a PfCRT orthologue from Neospora caninum (NcCRT). We have identified a conserved cysteine residue in PfCRT that results in elevated protein stability when mutated. Combining this mutation with the insertion of T4-lysozyme into a specific surface loop further augments PfCRT protein yield and thermostability. Screening also identified an NcCRT construct with an elevated purification yield. Furthermore it was possible to purify both PfCRT and NcCRT constructs at milligram-scales, with high purities and with size exclusion chromatography profiles that were consistent with monodispersed, homogeneous protein.
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Affiliation(s)
- David J Wright
- Astex Pharmaceuticals, 436 Cambridge Science Park, Milton Road, Cambridge CB4 0QA, UK
| | - Marc O'Reilly
- Astex Pharmaceuticals, 436 Cambridge Science Park, Milton Road, Cambridge CB4 0QA, UK
| | - Dominic Tisi
- Astex Pharmaceuticals, 436 Cambridge Science Park, Milton Road, Cambridge CB4 0QA, UK.
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Wu HC, Cha HJ, Bentley WE. Evaluating Baculovirus Infection Using Green Fluorescent Protein and Variants. Methods Mol Biol 2016; 1350:447-59. [PMID: 26820872 DOI: 10.1007/978-1-4939-3043-2_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
By use of a strategy incorporating the green fluorescent protein (GFP), facile and rapid monitoring and visualization of baculovirus infection in insect cells is possible in vivo. This chapter describes two techniques for simple determination of virus titer in the baculovirus expression system using GFP co-expression and rapid monitoring of Sf-9 insect cell infection using a combination of GFP and the early-to-late (ETL) promoter of the virus vector. Because of its early appearance, GFP, when placed under the control of ETL promoter, will facilitate vector construction, virus isolation, and titer determination.
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Affiliation(s)
- Hsuan-Chen Wu
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.,Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA
| | - Hyung Joon Cha
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - William E Bentley
- Fischell Department of Bioengineering, University of Maryland, 2226 Jeong H. Kim Engineering Building, College Park, MD, 20742, USA. .,Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA.
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3
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Abstract
The ease of use, robustness, cost-effectiveness, and posttranslational machinery make baculovirus expression system a popular choice for production of eukaryotic membrane proteins. This system can be readily adapted for high-throughput operations. This chapter outlines the techniques and procedures for cloning, transfection, small-scale production, and purification of membrane protein samples in a high-throughput manner.
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Belforte FS, Targovnik AM, González-Lebrero RM, Osorio Larroche C, Citterio CE, González-Sarmiento R, Miranda MV, Targovnik HM, Rivolta CM. Kinetic characterization of human thyroperoxidase. Normal and pathological enzyme expression in Baculovirus system: a molecular model of functional expression. Mol Cell Endocrinol 2015; 404:9-15. [PMID: 25576858 DOI: 10.1016/j.mce.2014.12.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/25/2014] [Accepted: 12/30/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND Human thyroperoxidase (hTPO) is a membrane-bound glycoprotein located at the apical membrane of the thyroid follicular cells which catalyzes iodide oxidation and organification in the thyroglobulin (TG) tyrosine residues, leading to the thyroid hormone synthesis by coupling of iodotyrosine residues. Mutations in hTPO gene are the main cause of iodine organification defects (IOD) in infants. METHODS We investigated the functional impact of hTPO gene missense mutations previously identified in our laboratory (p.C808R, p.G387R and p.P499L). In order to obtain the whole wild-type (WT) coding sequence of hTPO, sequential cloning strategy in pGEMT vector was carried out. Then, site-directed mutagenesis was performed. WT and mutant hTPOs were cloned into the pAcGP67B transfer vector and the recombinant proteins were expressed in Baculovirus System, purified and characterized by SDS-PAGE and Western blot. Moreover, we report for the first time the kinetic constants of hTPO, of both WT and mutant enzymes. RESULTS The functional evaluation of the recombinant hTPOs showed decreased activity in the three mutants with respect to WT. Regarding to the affinity for the substrate, the mutants showed higher Km values with respect to the WT. Additionally, the three mutants showed lower reaction efficiencies (Vmax/Km) with respect to WT hTPO. CONCLUSIONS We optimize the expression and purification of recombinant hTPOs using the Baculovirus System and we report for the first time the kinetic characterization of hTPOs.
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Affiliation(s)
- Fiorella S Belforte
- Laboratorio de Genética y Biología Molecular, Instituto de Inmunología, Genética y Metabolismo (INIGEM, CONICET-UBA), Hospital de Clínicas "José de San Martín", C1120AAR Buenos Aires, Argentina; Cátedra de Genética y Biología Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Alexandra M Targovnik
- Instituto de Nanobiotecnología (NANOBIOTEC, CONICET-UBA), Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Rodolfo M González-Lebrero
- Instituto de Química y Fisicoquímica Biológicas "Prof. Alejandro C. Paladini" (IQUIFIB, CONICET-UBA) and Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Carolina Osorio Larroche
- Laboratorio de Genética y Biología Molecular, Instituto de Inmunología, Genética y Metabolismo (INIGEM, CONICET-UBA), Hospital de Clínicas "José de San Martín", C1120AAR Buenos Aires, Argentina; Cátedra de Genética y Biología Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Cintia E Citterio
- Laboratorio de Genética y Biología Molecular, Instituto de Inmunología, Genética y Metabolismo (INIGEM, CONICET-UBA), Hospital de Clínicas "José de San Martín", C1120AAR Buenos Aires, Argentina; Cátedra de Genética y Biología Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Rogelio González-Sarmiento
- Unidad de Medicina Molecular-Departamento de Medicina, IBMCC and IBSAL, Universidad de Salamanca-CSIC, 37007 Salamanca, España
| | - María V Miranda
- Instituto de Nanobiotecnología (NANOBIOTEC, CONICET-UBA), Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Héctor M Targovnik
- Laboratorio de Genética y Biología Molecular, Instituto de Inmunología, Genética y Metabolismo (INIGEM, CONICET-UBA), Hospital de Clínicas "José de San Martín", C1120AAR Buenos Aires, Argentina; Cátedra de Genética y Biología Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Carina M Rivolta
- Laboratorio de Genética y Biología Molecular, Instituto de Inmunología, Genética y Metabolismo (INIGEM, CONICET-UBA), Hospital de Clínicas "José de San Martín", C1120AAR Buenos Aires, Argentina; Cátedra de Genética y Biología Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Buenos Aires, Argentina.
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6
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Coxsackievirus B3 VLPs purified by ion exchange chromatography elicit strong immune responses in mice. Antiviral Res 2014; 104:93-101. [DOI: 10.1016/j.antiviral.2014.01.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/20/2013] [Accepted: 01/20/2014] [Indexed: 01/29/2023]
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Airenne KJ, Hu YC, Kost TA, Smith RH, Kotin RM, Ono C, Matsuura Y, Wang S, Ylä-Herttuala S. Baculovirus: an insect-derived vector for diverse gene transfer applications. Mol Ther 2013; 21:739-49. [PMID: 23439502 PMCID: PMC3616530 DOI: 10.1038/mt.2012.286] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 12/11/2012] [Indexed: 01/23/2023] Open
Abstract
Insect-derived baculoviruses have emerged as versatile and safe workhorses of biotechnology. Baculovirus expression vectors (BEVs) have been applied widely for crop and forest protection, as well as safe tools for recombinant protein production in insect cells. However, BEVs ability to efficiently transduce noninsect cells is still relatively poorly recognized despite the fact that efficient baculovirus-mediated in vitro and ex vivo gene delivery into dormant and dividing vertebrate cells of diverse origin has been described convincingly by many authors. Preliminary proof of therapeutic potential has also been established in preclinical studies. This review summarizes the advantages and current status of baculovirus-mediated gene delivery. Stem cell transduction, preclinical animal studies, tissue engineering, vaccination, cancer gene therapy, viral vector production, and drug discovery are covered.
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Affiliation(s)
- Kari J Airenne
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Yu-Chen Hu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Thomas A Kost
- Biological Reagents and Assay Development, GlaxoSmithKline R&D, Research Triangle Park, North Carolina, USA
| | - Richard H Smith
- Molecular Virology and Gene Therapy Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert M Kotin
- Molecular Virology and Gene Therapy Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Chikako Ono
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Yoshiharu Matsuura
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Shu Wang
- Institute of Bioengineering and Nanotechnology, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Seppo Ylä-Herttuala
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
- Research Unit, Kuopio University Hospital, Kuopio, Finland
- Gene Therapy Unit, Kuopio University Hospital, Kuopio, Finland
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8
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Abstract
Historically, it has been proved difficult to adapt the traditional baculovirus expression systems to an automated platform because of the complexity of the processes involved. One of the major bottlenecks is the selection of recombinant from parental viruses. We have developed a bacmid vector (flashBAC™) that does not require any form of selection pressure to separate recombinant virus from nonrecombinant parental virus. The method relies on homologous recombination in insect cells between a transfer plasmid containing the gene of interest and a replication-deficient bacmid. The gene of interest replaces the bacterial replicon at the polyhedrin locus, simultaneously restoring a virus gene essential for replication, and as only recombinant virus can replicate, no further separation techniques are required. This chapter describes methods for producing and expression testing multiple recombinant baculoviruses on automated platforms using the flashBAC system.
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Affiliation(s)
- Richard B Hitchman
- Oxford Expression Technologies Ltd, Oxford Brookes University, Oxford, UK.
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Yumerefendi H, Desravines DC, Hart DJ. Library-based methods for identification of soluble expression constructs. Methods 2011; 55:38-43. [DOI: 10.1016/j.ymeth.2011.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 06/09/2011] [Accepted: 06/11/2011] [Indexed: 01/10/2023] Open
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10
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Nie Y, Viola C, Bieniossek C, Trowitzsch S, Vijay-Achandran LS, Chaillet M, Garzoni F, Berger I. Getting a grip on complexes. Curr Genomics 2011; 10:558-72. [PMID: 20514218 PMCID: PMC2817887 DOI: 10.2174/138920209789503923] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Revised: 07/15/2009] [Accepted: 07/24/2009] [Indexed: 02/03/2023] Open
Abstract
We are witnessing tremendous advances in our understanding of the organization of life. Complete genomes are being deciphered with ever increasing speed and accuracy, thereby setting the stage for addressing the entire gene product repertoire of cells, towards understanding whole biological systems. Advances in bioinformatics and mass spectrometric techniques have revealed the multitude of interactions present in the proteome. Multiprotein complexes are emerging as a paramount cornerstone of biological activity, as many proteins appear to participate, stably or transiently, in large multisubunit assemblies. Analysis of the architecture of these assemblies and their manifold interactions is imperative for understanding their function at the molecular level. Structural genomics efforts have fostered the development of many technologies towards achieving the throughput required for studying system-wide single proteins and small interaction motifs at high resolution. The present shift in focus towards large multiprotein complexes, in particular in eukaryotes, now calls for a likewise concerted effort to develop and provide new technologies that are urgently required to produce in quality and quantity the plethora of multiprotein assemblies that form the complexome, and to routinely study their structure and function at the molecular level. Current efforts towards this objective are summarized and reviewed in this contribution.
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Affiliation(s)
- Yan Nie
- European Molecular Biology Laboratory (EMBL), Grenoble Outstation and Unit of Virus Host-Cell Interactions (UVHCI), UJF-EMBL-CNRS, UMR 5233, 6 rue Jules Horowitz, 38042 Grenoble CEDEX 9, France
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Roldão A, Vicente T, Peixoto C, Carrondo MJT, Alves PM. Quality control and analytical methods for baculovirus-based products. J Invertebr Pathol 2011; 107 Suppl:S94-105. [PMID: 21784235 DOI: 10.1016/j.jip.2011.05.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 01/24/2011] [Indexed: 11/28/2022]
Affiliation(s)
- António Roldão
- Instituto de Tecnologia Química e Biológica/Universidade Nova de Lisboa, Apartado 127, P-2781-901 Oeiras, Portugal
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Lesch HP, Makkonen KE, Laitinen A, Määttä AM, Närvänen O, Airenne KJ, Ylä-Herttuala S. Requirements for baculoviruses for clinical gene therapy applications. J Invertebr Pathol 2011; 107 Suppl:S106-12. [PMID: 21784225 DOI: 10.1016/j.jip.2011.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 01/23/2011] [Indexed: 11/30/2022]
Affiliation(s)
- Hanna P Lesch
- AI Virtanen Institute Department of Biotechnology and Molecular Medicine, University of Eastern Finland/Kuopio, Finland
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13
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Chen CY, Lin CY, Chen GY, Hu YC. Baculovirus as a gene delivery vector: recent understandings of molecular alterations in transduced cells and latest applications. Biotechnol Adv 2011; 29:618-31. [PMID: 21550393 PMCID: PMC7126054 DOI: 10.1016/j.biotechadv.2011.04.004] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 04/15/2011] [Accepted: 04/15/2011] [Indexed: 12/13/2022]
Abstract
Baculovirus infects insects in nature and is non-pathogenic to humans, but can transduce a broad range of mammalian and avian cells. Thanks to the biosafety, large cloning capacity, low cytotoxicity and non-replication nature in the transduced cells as well as the ease of manipulation and production, baculovirus has gained explosive popularity as a gene delivery vector for a wide variety of applications. This article extensively reviews the recent understandings of the molecular mechanisms pertinent to baculovirus entry and cellular responses, and covers the latest advances in the vector improvements and applications, with special emphasis on antiviral therapy, cancer therapy, regenerative medicine and vaccine.
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Affiliation(s)
- Chi-Yuan Chen
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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Vicente T, Fáber R, Alves PM, Carrondo MJT, Mota JPB. Impact of ligand density on the optimization of ion-exchange membrane chromatography for viral vector purification. Biotechnol Bioeng 2011; 108:1347-59. [PMID: 21294110 DOI: 10.1002/bit.23058] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 12/04/2010] [Accepted: 12/23/2010] [Indexed: 12/12/2022]
Abstract
The effect of ligand density on anion-exchange membrane chromatography (AEXmc) for the purification of recombinant baculoviruses (rBVs), potential viral vectors in clinical applications, is studied by surface plasmon resonance on customized AEX surfaces and gradient elution experiments on Sartobind D membrane prototypes with different diethylamine ligand densities, complemented by dynamic light scattering analysis for estimation of the hydrodynamic particle size of the various biologics. A chromatographic-column model based on the steric mass action model of ion exchange is employed to analyze the gradient-elution AEXmc experiments, extrapolate the results to other operating conditions, and provide directions for process improvement. Although counterintuitively, the experimental evidence provided in this study shows that the lowering of ligand density is beneficial for rBV purification by AEXmc in bind-and-elute-mode, because it decreases the residual concentrations of host cell protein, dsDNA, and non-infective rBVs in the eluted product cut, and increases the overall yield by roughly 20% over current standard values. Overall, we present a case study on how rational design can streamline downstream process development.
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Airenne KJ, Makkonen KE, Mähönen AJ, Ylä-Herttuala S. Baculoviruses mediate efficient gene expression in a wide range of vertebrate cells. Methods Mol Biol 2011; 737:279-301. [PMID: 21590402 DOI: 10.1007/978-1-61779-095-9_12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Baculovirus expression vector system (BEVS) is well known as a feasible and safe technology to produce recombinant (re-)proteins in a eukaryotic milieu of insect cells. However, its proven power in gene delivery and gene therapy is still poorly recognized. The basis of BEVS lies in large enveloped DNA viruses derived from insects, the prototype virus being Autographa californica multiple nucleopolyhedrovirus (AcMNPV). Infection of insect cell culture with a virus encoding a desired transgene under powerful baculovirus promoter leads to re-protein production in high quantities. Although the replication of AcMNPV is highly insect specific in nature, it can penetrate and transduce a wide range of cells of other origin. Efficient transduction requires only virus arming with an expression cassette active in the cells under investigation. The inherent safety, ease and speed of virus generation in high quantities, low cytotoxicity and extreme transgene capacity and tropism provides many advantages for gene delivery over the other viral vectors typically derived from human pathogens.
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Affiliation(s)
- Kari J Airenne
- Department of Molecular Medicine, A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland.
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O'Grady M, Batchelor RH, Scheyhing K, Kemp CW, Hanson GT, Lakshmipathy U. BacMam-mediated gene delivery into multipotent mesenchymal stromal cells. Methods Mol Biol 2011; 698:485-504. [PMID: 21431539 DOI: 10.1007/978-1-60761-999-4_34] [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] [Indexed: 05/30/2023]
Abstract
Baculoviruses have been used over the last several decades for high-level protein production in insect cells. Recently, modified baculovirus containing a mammalian promoter, known as BacMam virus, has been shown to give high transduction efficiencies across several cell types with minimal cytopathic effects. Cell types amenable to BacMam transduction include primary and adult stem cells. The shuttle vectors used in the construction of BacMam viruses can hold gene fragments up to 38 kb in size, and multiple BacMam viruses can be used in a single transduction for the delivery of more than one gene. BacMam technology has been used in the delivery and expression of targeted fluorescent protein cellular markers, small interfering RNAi, and extensively in the development of cell-based assays. BacMam offers an ideal method for the delivery and expression of large genes in hard-to-transfect cells such as primary and adult stem cells. In this chapter, we describe methods of generating high titer stocks of BacMam for transducing MSC and their derivatives.
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Affiliation(s)
- Michael O'Grady
- Primary and Stem Cell Systems, Life Technologies, Carlsbad, CA, USA
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Lo WH, Chen CY, Yeh CN, Lin CY, Hu YC. Rapid baculovirus titration based on regulatable green fluorescent protein expression in mammalian cells. Enzyme Microb Technol 2010; 48:13-8. [PMID: 22112765 DOI: 10.1016/j.enzmictec.2010.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 10/19/2022]
Abstract
Baculovirus is a promising gene delivery vector and can be titrated by constitutive EGFP expression in HeLa cells, which, however, might interfere with target transgene expression and impart cytotoxicity. Here we constructed Bac-ME accommodating egfp under the inducible metallothionein promoter and Bac-MECB harboring an additional BMP-2 gene. Bac-ME effectively transduced HeLa cells with minimal leaky expression, but expressed EGFP robustly upon induction with ZnSO(4), hence allowing for virus titration by transducing HeLa cells with serially diluted virus, subsequent ZnSO(4) induction and flow cytometry analysis of EGFP-positive cells. The titration protocol enabled the generation of discernable titration curves, determination of transducing titers, and discrimination of the transducing abilities of different virus batches. After titration, cell transduction with pre-determined Bac-ME dose revealed consistent transduction efficiency dependence on the dose, regardless of virus batch and cell type. Bac-MECB was similarly titrated by inducible EGFP expression and used to transduce de-differentiated articular chondrocytes without EGFP induction. BMP-2 expression was proportional to the Bac-MECB dose and promoted cartilage-specific matrix synthesis, implicating the potential of Bac-MECB in restoring chondrocyte differentiation. These data confirmed that regulatable EGFP expression enabled rapid, reliable baculovirus titration without interference with subsequent applications.
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Affiliation(s)
- Wen-Hsin Lo
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
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Vicente T, Peixoto C, Alves PM, Carrondo MJT. Modeling electrostatic interactions of baculovirus vectors for ion-exchange process development. J Chromatogr A 2010; 1217:3754-64. [PMID: 20444457 DOI: 10.1016/j.chroma.2010.03.059] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 03/22/2010] [Accepted: 03/30/2010] [Indexed: 10/19/2022]
Abstract
Product-related impurities constitute a major burden in the production of recombinant viral vectors for gene therapy and vaccination; it impairs not only the biological efficacy of the preparation but the process yield/productivity. Recombinant baculovirus was used as an enveloped virus model to address this issue. Given that ion-exchange chromatography is a process of choice for purification of viral vectors, the analysis of the electrostatic behavior can be instrumental for the improvement of impurity removal. The main species, product (infective virus particle) and product-derived impurities (dsDNA-, glycoprotein-, and envelope-deprived baculovirus particles), were isolated and correspondent zeta potentials were analyzed through dynamic light scattering. A model of the virus based on the viral components critical for biological function is proposed. The contribution of these viral components to the overall particle electrostatic interaction energy profile (calculated between the particle and a putative ion-exchange surface) was assessed as a function of ionic strength and pH. This resulted in a deterministic tool capable of distinguishing the electrostatic properties of the infective virus particle from the major virus-related impurities. Within an ion-exchange bind-elute process, this knowledge helps narrow the optimization space in early stage process development for viral vectors by predicting the best selectivity conditions.
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Affiliation(s)
- Tiago Vicente
- IBET, Apartado 12, P-2781-901 Oeiras, Portugal; ITQB-UNL, P-2780-157 Oeiras, Portugal
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