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Bidgood SR, Samolej J, Novy K, Collopy A, Albrecht D, Krause M, Burden JJ, Wollscheid B, Mercer J. Poxviruses package viral redox proteins in lateral bodies and modulate the host oxidative response. PLoS Pathog 2022; 18:e1010614. [PMID: 35834477 PMCID: PMC9282662 DOI: 10.1371/journal.ppat.1010614] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 05/24/2022] [Indexed: 01/23/2023] Open
Abstract
All poxviruses contain a set of proteinaceous structures termed lateral bodies (LB) that deliver viral effector proteins into the host cytosol during virus entry. To date, the spatial proteotype of LBs remains unknown. Using the prototypic poxvirus, vaccinia virus (VACV), we employed a quantitative comparative mass spectrometry strategy to determine the poxvirus LB proteome. We identified a large population of candidate cellular proteins, the majority being mitochondrial, and 15 candidate viral LB proteins. Strikingly, one-third of these are VACV redox proteins whose LB residency could be confirmed using super-resolution microscopy. We show that VACV infection exerts an anti-oxidative effect on host cells and that artificial induction of oxidative stress impacts early and late gene expression as well as virion production. Using targeted repression and/or deletion viruses we found that deletion of individual LB-redox proteins was insufficient for host redox modulation suggesting there may be functional redundancy. In addition to defining the spatial proteotype of VACV LBs, these findings implicate poxvirus redox proteins as potential modulators of host oxidative anti-viral responses and provide a solid starting point for future investigations into the role of LB resident proteins in host immunomodulation.
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Affiliation(s)
- Susanna R. Bidgood
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Jerzy Samolej
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Karel Novy
- Swiss Federal Institute of Technology (ETH Zürich), Department of Health Sciences and Technology (D-HEST), Institute of Translational Medicine (ITM), Zürich, Switzerland
| | - Abigail Collopy
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - David Albrecht
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Melanie Krause
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Jemima J. Burden
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Bernd Wollscheid
- Swiss Federal Institute of Technology (ETH Zürich), Department of Health Sciences and Technology (D-HEST), Institute of Translational Medicine (ITM), Zürich, Switzerland
- Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Jason Mercer
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
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2
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Barreto-Vieira DF, Couto-Lima D, Jácome FC, Caldas GC, Barth OM. Dengue, Yellow Fever, Zika and Chikungunya epidemic arboviruses in Brazil: ultrastructural aspects. Mem Inst Oswaldo Cruz 2021; 115:e200278. [PMID: 33566939 PMCID: PMC7860610 DOI: 10.1590/0074-02760200278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/21/2020] [Indexed: 08/30/2023] Open
Abstract
BACKGROUND The impact of arbovirus cocirculation in Brazil is unknown. Dengue virus (DENV) reinfection may result in more intense viraemia or immunopathology, leading to more severe disease. The Zika virus (ZIKV) epidemic in the Americas provided pathogenicity evidence that had not been previously observed in flavivirus infections. In contrast to other flaviviruses, electron microscopy studies have shown that ZIKV may replicate in viroplasm-like structures. Flaviviruses produce an ensemble of structurally different virions, collectively contributing to tissue tropism and virus dissemination. OBJECTIVES AND METHODS In this work, the Aedes albopictus mosquito cell lineage (C6/36 cells) and kidney epithelial cells from African green monkeys (Vero cells) were infected with samples of the main circulating arboviruses in Brazil [DENV-1, DENV-2, DENV-3, DENV-4, ZIKV, Yellow Fever virus (YFV) and Chikungunya virus (CHIKV)], and ultrastructural studies by transmission electron microscopy were performed. FINDINGS We observed that ZIKV, the DENV serotypes, YFV and CHIKV particles are spherical. ZIKV, DENV-1, -2, -3 and -4 presented diameters of 40-50 nm, and CHIKV presented approximate diameters of 50-60 nm. Viroplasm-like structures was observed in ZIKV replication cycle. MAIN CONCLUSIONS The morphogenesis of these arboviruses is similar to what has been presented in previous studies. However, we understand that further studies are needed to investigate the relationship between viroplasm-like structures and ZIKV replication dynamics.
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Affiliation(s)
- Debora Ferreira Barreto-Vieira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Morfologia e Morfogênese Viral, Rio de Janeiro, RJ, Brasil
| | - Dinair Couto-Lima
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Mosquitos Transmissores de Hematozoários, Rio de Janeiro, RJ, Brasil
| | - Fernanda Cunha Jácome
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Morfologia e Morfogênese Viral, Rio de Janeiro, RJ, Brasil
| | - Gabriela Cardoso Caldas
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Morfologia e Morfogênese Viral, Rio de Janeiro, RJ, Brasil
| | - Ortrud Monika Barth
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Morfologia e Morfogênese Viral, Rio de Janeiro, RJ, Brasil
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Giotis ES, Laidlaw SM, Bidgood SR, Albrecht D, Burden JJ, Robey RC, Mercer J, Skinner MA. Modulation of Early Host Innate Immune Response by an Avipox Vaccine Virus' Lateral Body Protein. Biomedicines 2020; 8:E634. [PMID: 33352813 PMCID: PMC7766033 DOI: 10.3390/biomedicines8120634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/14/2022] Open
Abstract
The avian pathogen fowlpox virus (FWPV) has been successfully used as a vaccine vector in poultry and humans, but relatively little is known about its ability to modulate host antiviral immune responses in these hosts, which are replication-permissive and nonpermissive, respectively. FWPV is highly resistant to avian type I interferon (IFN) and able to completely block the host IFN-response. Microarray screening of host IFN-regulated gene expression in cells infected with 59 different, nonessential FWPV gene knockout mutants revealed that FPV184 confers immunomodulatory capacity. We report that the FPV184-knockout virus (FWPVΔ184) induces the cellular IFN response as early as 2 h postinfection. The wild-type, uninduced phenotype can be rescued by transient expression of FPV184 in FWPVΔ184-infected cells. Ectopic expression of FPV184 inhibited polyI:C activation of the chicken IFN-β promoter and IFN-α activation of the chicken Mx1 promoter. Confocal and correlative super-resolution light and electron microscopy demonstrated that FPV184 has a functional nuclear localisation signal domain and is packaged in the lateral bodies of the virions. Taken together, these results provide a paradigm for a late poxvirus structural protein packaged in the lateral bodies, capable of suppressing IFN induction early during the next round of infection.
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Affiliation(s)
- Efstathios S. Giotis
- Section of Virology, School of Medicine, St Mary’s Campus, Imperial College, London W2 1PG, UK; (S.M.L.); (R.C.R.); (M.A.S.)
- School of Life Sciences, University of Essex, Colchester C04 3SQ, UK
| | - Stephen M. Laidlaw
- Section of Virology, School of Medicine, St Mary’s Campus, Imperial College, London W2 1PG, UK; (S.M.L.); (R.C.R.); (M.A.S.)
| | - Susanna R. Bidgood
- Medical Research Council-Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; (S.R.B.); (D.A.); (J.J.B.); (J.M.)
| | - David Albrecht
- Medical Research Council-Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; (S.R.B.); (D.A.); (J.J.B.); (J.M.)
| | - Jemima J. Burden
- Medical Research Council-Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; (S.R.B.); (D.A.); (J.J.B.); (J.M.)
| | - Rebecca C. Robey
- Section of Virology, School of Medicine, St Mary’s Campus, Imperial College, London W2 1PG, UK; (S.M.L.); (R.C.R.); (M.A.S.)
| | - Jason Mercer
- Medical Research Council-Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; (S.R.B.); (D.A.); (J.J.B.); (J.M.)
| | - Michael A. Skinner
- Section of Virology, School of Medicine, St Mary’s Campus, Imperial College, London W2 1PG, UK; (S.M.L.); (R.C.R.); (M.A.S.)
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4
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Mirzakhanyan Y, Gershon P. The Vaccinia virion: Filling the gap between atomic and ultrastructure. PLoS Pathog 2019; 15:e1007508. [PMID: 30615658 PMCID: PMC6336343 DOI: 10.1371/journal.ppat.1007508] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/17/2019] [Accepted: 12/06/2018] [Indexed: 01/19/2023] Open
Abstract
We have investigated the molecular-level structure of the Vaccinia virion in situ by protein-protein chemical crosslinking, identifying 4609 unique-mass crosslink ions at an effective FDR of 0.33%, covering 2534 unique pairs of crosslinked protein positions, 625 of which were inter-protein. The data were statistically non-random and rational in the context of known structures, and showed biological rationality. Crosslink density strongly tracked the individual proteolytic maturation products of p4a and p4b, the two major virion structural proteins, and supported the prediction of transmembrane domains within membrane proteins. A clear sub-network of four virion structural proteins provided structural insights into the virion core wall, and proteins VP8 and A12 formed a strongly-detected crosslinked pair with an apparent structural role. A strongly-detected sub-network of membrane proteins A17, H3, A27 and A26 represented an apparent interface of the early-forming virion envelope with structures added later during virion morphogenesis. Protein H3 seemed to be the central hub not only for this sub-network but also for an 'attachment protein' sub-network comprising membrane proteins H3, ATI, CAHH(D8), A26, A27 and G9. Crosslinking data lent support to a number of known interactions and interactions within known complexes. Evidence is provided for the membrane targeting of genome telomeres. In covering several orders of magnitude in protein abundance, this study may have come close to the bottom of the protein-protein crosslinkome of an intact organism, namely a complex animal virus.
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Affiliation(s)
- Yeva Mirzakhanyan
- Department of Molecular Biology & Biochemistry, UC-Irvine, Irvine, California, United States of America
| | - Paul Gershon
- Department of Molecular Biology & Biochemistry, UC-Irvine, Irvine, California, United States of America
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5
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Enigmatic origin of the poxvirus membrane from the endoplasmic reticulum shown by 3D imaging of vaccinia virus assembly mutants. Proc Natl Acad Sci U S A 2017; 114:E11001-E11009. [PMID: 29203656 DOI: 10.1073/pnas.1716255114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The long-standing inability to visualize connections between poxvirus membranes and cellular organelles has led to uncertainty regarding the origin of the viral membrane. Indeed, there has been speculation that viral membranes form de novo in cytoplasmic factories. Another possibility, that the connections are too short-lived to be captured by microscopy during a normal infection, motivated us to identify and characterize virus mutants that are arrested in assembly. Five conserved vaccinia virus proteins, referred to as Viral Membrane Assembly Proteins (VMAPs), that are necessary for formation of immature virions were found. Transmission electron microscopy studies of two VMAP deletion mutants had suggested retention of connections between viral membranes and the endoplasmic reticulum (ER). We now analyzed cells infected with each of the five VMAP deletion mutants by electron tomography, which is necessary to validate membrane continuity, in addition to conventional transmission electron microscopy. In all cases, connections between the ER and viral membranes were demonstrated by 3D reconstructions, supporting a role for the VMAPs in creating and/or stabilizing membrane scissions. Furthermore, coexpression of the viral reticulon-like transmembrane protein A17 and the capsid-like scaffold protein D13 was sufficient to form similar ER-associated viral structures in the absence of other major virion proteins. Determination of the mechanism of ER disruption during a normal VACV infection and the likely participation of both viral and cell proteins in this process may provide important insights into membrane dynamics.
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6
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Barreto-Vieira DF, Jácome FC, da Silva MAN, Caldas GC, de Filippis AMB, de Sequeira PC, de Souza EM, Andrade AA, Manso PPDA, Trindade GF, Lima SMB, Barth OM. Structural investigation of C6/36 and Vero cell cultures infected with a Brazilian Zika virus. PLoS One 2017; 12:e0184397. [PMID: 28898286 PMCID: PMC5595330 DOI: 10.1371/journal.pone.0184397] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 08/23/2017] [Indexed: 12/22/2022] Open
Abstract
Zika virus (ZIKV) is a member of the flavivirus genus, and its genome is approximately 10.8 kilobases of positive-strand RNA enclosed in a capsid and surrounded by a membrane. Studies on the replication dynamics of ZIKV are scarce, which limits the development of antiviral agents and vaccines directed against ZIKV. In this study, Aedes albopictus mosquito lineage cells (C6/36 cells) and African green monkey kidney epithelial cells (Vero cells) were inoculated with a ZIKV sample isolated from a Brazilian patient, and the infection was characterized by immunofluorescence staining, phase contrast light microscopy, transmission electron microscopy and real-time RT-PCR. The infection was observed in both cell lineages, and ZIKV particles were observed inside lysosomes, the rough endoplasmic reticulum and viroplasm-like structures. The susceptibility of C6/36 and Vero cells to ZIKV infection was demonstrated. Moreover, this study showed that part of the replicative cycle may occur within viroplasm-like structures, which has not been previously demonstrated in other flaviviruses.
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Affiliation(s)
- Debora Ferreira Barreto-Vieira
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | - Fernanda Cunha Jácome
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | - Marcos Alexandre Nunes da Silva
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | - Gabriela Cardoso Caldas
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | | | | | - Elen Mello de Souza
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | - Audrien Alves Andrade
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | | | - Gisela Freitas Trindade
- Laboratory of Virological Technology, Bio-Manguinhos, Avenida Brasil, Rio de Janeiro, RJ, Brazil
| | | | - Ortrud Monika Barth
- Laboratory of Morphology and Viral Morphogenesis, Instituto Oswaldo Cruz, Fiocruz, Avenida Brasil, Rio de Janeiro, RJ, Brazil
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7
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The vaccinia virus E6 protein influences virion protein localization during virus assembly. Virology 2015; 482:147-56. [PMID: 25863879 DOI: 10.1016/j.virol.2015.02.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 11/22/2022]
Abstract
Vaccinia virus mutants in which expression of the virion core protein gene E6R is repressed are defective in virion morphogenesis. E6 deficient infections fail to properly package viroplasm into viral membranes, resulting in an accumulation of empty immature virions and large aggregates of viroplasm. We have used immunogold electron microscopy and immunofluorescence confocal microscopy to assess the intracellular localization of several virion structural proteins and enzymes during E6R mutant infections. We find that during E6R mutant infections virion membrane proteins and virion transcription enzymes maintain a normal localization within viral factories while several major core and lateral body proteins accumulate in aggregated virosomes. The results support a model in which vaccinia virions are assembled from at least three substructures, the membrane, the viroplasm and a "pre-nucleocapsid", and that the E6 protein is essential for maintaining proper localization of the seven-protein complex and the viroplasm during assembly.
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8
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Liu L, Cooper T, Howley PM, Hayball JD. From crescent to mature virion: vaccinia virus assembly and maturation. Viruses 2014; 6:3787-808. [PMID: 25296112 PMCID: PMC4213562 DOI: 10.3390/v6103787] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 09/29/2014] [Accepted: 10/02/2014] [Indexed: 01/22/2023] Open
Abstract
Vaccinia virus (VACV) has achieved unprecedented success as a live viral vaccine for smallpox which mitigated eradication of the disease. Vaccinia virus has a complex virion morphology and recent advances have been made to answer some of the key outstanding questions, in particular, the origin and biogenesis of the virion membrane, the transformation from immature virion (IV) to mature virus (MV), and the role of several novel genes, which were previously uncharacterized, but have now been shown to be essential for VACV virion formation. This new knowledge will undoubtedly contribute to the rational design of safe, immunogenic vaccine candidates, or effective antivirals in the future. This review endeavors to provide an update on our current knowledge of the VACV maturation processes with a specific focus on the initiation of VACV replication through to the formation of mature virions.
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Affiliation(s)
- Liang Liu
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, Adelaide, 5000, SA, Australia.
| | - Tamara Cooper
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, Adelaide, 5000, SA, Australia.
| | - Paul M Howley
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, Adelaide, 5000, SA, Australia.
| | - John D Hayball
- Experimental Therapeutics Laboratory, Hanson Institute and Sansom Institute, Adelaide, 5000, SA, Australia.
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9
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Maruri-Avidal L, Weisberg AS, Moss B. Vaccinia virus L2 protein associates with the endoplasmic reticulum near the growing edge of crescent precursors of immature virions and stabilizes a subset of viral membrane proteins. J Virol 2011; 85:12431-41. [PMID: 21917978 PMCID: PMC3209352 DOI: 10.1128/jvi.05573-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 09/04/2011] [Indexed: 12/11/2022] Open
Abstract
The initial step in poxvirus morphogenesis, the formation of crescent membranes, occurs within cytoplasmic factories. L2 is one of several vaccinia virus proteins known to be necessary for formation of crescents and the only one synthesized early in infection. Virus replication was unaffected when the L2R open reading frame was replaced by L2R containing an N-terminal epitope tag while retaining the original promoter. L2 colocalized with the endoplasmic reticulum (ER) protein calnexin throughout the cytoplasm of infected and transfected cells. Topological studies indicated that the N terminus of L2 is exposed to the cytoplasm with the hydrophobic C terminus anchored in the ER. Using immunogold labeling and electron microscopy, L2 was detected in tubular membranes outside factories and inside factories near crescents and close to the edge or rim of crescents; a similar labeling pattern was found for the ER luminal protein disulfide isomerase (PDI). The phenotype of L2 conditional lethal mutants and the localization of L2 suggest that it participates in elongation of crescents by the addition of ER membrane to the growing edge. Small amounts of L2 and PDI were detected within immature and mature virions, perhaps trapped during assembly. The repression of L2, as well as A11 and A17, two other proteins that are required for viral crescent formation, profoundly decreased the stability of a subset of viral membrane proteins including those comprising the entry-fusion complex. To avoid degradation, these unstable membrane proteins may need to directly insert into the viral membrane or be rapidly shunted there from the ER.
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Affiliation(s)
- Liliana Maruri-Avidal
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-3210
| | - Andrea S. Weisberg
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-3210
| | - Bernard Moss
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-3210
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10
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He LB, Ke F, Zhang QY. Rana grylio virus as a vector for foreign gene expression in fish cells. Virus Res 2011; 163:66-73. [PMID: 21889962 DOI: 10.1016/j.virusres.2011.08.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/16/2011] [Accepted: 08/18/2011] [Indexed: 01/25/2023]
Abstract
In the present study, Rana grylio virus (RGV, an iridovirus) thymidine kinase (TK) gene and viral envelope protein 53R gene were chosen as targets for foreign gene insertion. ΔTK-RGV and Δ53R-RGV, two recombinant RGV, expressing enhanced green fluorescence protein (EGFP) were constructed and analyzed in Epithelioma papulosum cyprinid (EPC) cells. The EGFP gene which fused to the virus major capsid protein (MCP) promoter p50 was inserted into TK and 53R gene loci of RGV, respectively. Cells infected with these two recombinant viruses not only displayed plaques, but also emitted strong green fluorescence under fluorescence microscope, providing a simple method for selection and purification of recombinant viruses. ΔTK-RGV was purified by seven successive rounds of plaque isolation and could be stably propagated in EPC cells. All of the plaques produced by the purified recombinant virus emitted green fluorescence. However, Δ53R-RGV was hard to be purified even through twenty rounds of plaque isolation. The purified recombinant virus ΔTK-RGV was verified by PCR analysis and Western blotting. These results showed EGFP was expressed in ΔTK-RGV infected cells. Furthermore, one-step growth curves and electron microscopy revealed that infection with recombinant ΔTK-RGV and wild-type RGV are similar. Therefore, RGV was demonstrated could be as a viral vector for foreign gene expression in fish cells.
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Affiliation(s)
- Li-Bo He
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan 430072, China
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11
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Chlanda P, Carbajal MA, Kolovou A, Hamasaki M, Cyrklaff M, Griffiths G, Krijnse-Locker J. Vaccinia virus lacking A17 induces complex membrane structures composed of open membrane sheets. Arch Virol 2011; 156:1647-53. [PMID: 21590268 DOI: 10.1007/s00705-011-1012-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
The vaccinia virus (VACV) precursor membrane, the crescent, consists of an open membrane sheet and is formed by rupture of a cellular compartment. Here, we asked whether A17, a viral membrane protein, plays a role in membrane rupture. Without A17 synthesis, crescents are not formed, and instead, tubular and vesicular membranes accumulate (Rodriguez et al. in J Virol 69:4640-4648, 1). We used electron tomography (ET) to analyze whether the viral membranes lacking A17 consist of open membrane sheets. Tubular, vesicular and so far not described onion-shaped membranes, which consisted of open membrane sheets, were seen. Thus, the data show that membrane rupture occurs independently of the A17 protein.
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Affiliation(s)
- Petr Chlanda
- European Molecular Biology Laboratory, Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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12
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Structure/Function analysis of the vaccinia virus F18 phosphoprotein, an abundant core component required for virion maturation and infectivity. J Virol 2010; 84:6846-60. [PMID: 20392848 DOI: 10.1128/jvi.00399-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Poxvirus virions, whose outer membrane surrounds two lateral bodies and a core, contain at least 70 different proteins. The F18 phosphoprotein is one of the most abundant core components and is essential for the assembly of mature virions. We report here the results of a structure/function analysis in which the role of conserved cysteine residues, clusters of charged amino acids and clusters of hydrophobic/aromatic amino acids have been assessed. Taking advantage of a recombinant virus in which F18 expression is IPTG (isopropyl-beta-d-thiogalactopyranoside) dependent, we developed a transient complementation assay to evaluate the ability of mutant alleles of F18 to support virion morphogenesis and/or to restore the production of infectious virus. We have also examined protein-protein interactions, comparing the ability of mutant and WT F18 proteins to interact with WT F18 and to interact with the viral A30 protein, another essential core component. We show that F18 associates with an A30-containing multiprotein complex in vivo in a manner that depends upon clusters of hydrophobic/aromatic residues in the N' terminus of the F18 protein but that it is not required for the assembly of this complex. Finally, we confirmed that two PSSP motifs within F18 are the sites of phosphorylation by cellular proline-directed kinases in vitro and in vivo. Mutation of both of these phosphorylation sites has no apparent impact on virion morphogenesis but leads to the assembly of virions with significantly reduced infectivity.
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13
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The E6 protein from vaccinia virus is required for the formation of immature virions. Virology 2010; 399:201-11. [PMID: 20116821 DOI: 10.1016/j.virol.2010.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 01/04/2010] [Accepted: 01/07/2010] [Indexed: 11/22/2022]
Abstract
An IPTG-inducible mutant in the E6R gene of vaccinia virus was used to study the role of the E6 virion core protein in viral replication. In the absence of the inducer, the mutant exhibited a normal pattern DNA replication, concatemer resolution and late gene expression, but it showed an inhibition of virion structural protein processing it failed to produce infectious particles. Electron microscopic analysis showed that in the absence of IPTG viral morphogenesis was arrested before IV formation: crescents, aberrant or empty IV-like structures, and large aggregated virosomes were observed throughout the cytoplasm. The addition of IPTG to release a 12-h block showed that virus infectious particles could be formed in the absence of de novo DNA synthesis. Our observations show that in the absence of E6 the association of viroplasm with viral membrane crescents is impaired.
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14
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Resch W, Weisberg AS, Moss B. Expression of the highly conserved vaccinia virus E6 protein is required for virion morphogenesis. Virology 2009; 386:478-85. [PMID: 19217136 DOI: 10.1016/j.virol.2009.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 01/05/2009] [Accepted: 01/09/2009] [Indexed: 11/29/2022]
Abstract
The vaccinia virus E6R gene (VACVWR062) is conserved in all members of the poxvirus family and encodes a protein associated with the mature virion. We confirmed this association and provided evidence for an internal location. An inducible mutant that conditionally expresses E6 was constructed. In the absence of inducer, plaque formation and virus production were severely inhibited in several cell lines, whereas some replication occurred in others. This difference could be due to variation in the stringency of repression, since we could not isolate a stable deletion mutant even in the more "permissive" cells. Under non-permissive conditions, viral late proteins were synthesized but processing of core proteins was inefficient, indicative of an assembly block. Transmission electron microscopy of sections of cells infected with the mutant in the absence of inducer revealed morphogenetic defects with crescents and empty immature virions adjacent to dense inclusions of viroplasm. Mature virions were infrequent and cores appeared to have lucent centers.
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Affiliation(s)
- Wolfgang Resch
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-3210, USA
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15
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Netherton C, Moffat K, Brooks E, Wileman T. A guide to viral inclusions, membrane rearrangements, factories, and viroplasm produced during virus replication. Adv Virus Res 2007; 70:101-82. [PMID: 17765705 PMCID: PMC7112299 DOI: 10.1016/s0065-3527(07)70004-0] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Virus replication can cause extensive rearrangement of host cell cytoskeletal and membrane compartments leading to the “cytopathic effect” that has been the hallmark of virus infection in tissue culture for many years. Recent studies are beginning to redefine these signs of viral infection in terms of specific effects of viruses on cellular processes. In this chapter, these concepts have been illustrated by describing the replication sites produced by many different viruses. In many cases, the cellular rearrangements caused during virus infection lead to the construction of sophisticated platforms in the cell that concentrate replicase proteins, virus genomes, and host proteins required for replication, and thereby increase the efficiency of replication. Interestingly, these same structures, called virus factories, virus inclusions, or virosomes, can recruit host components that are associated with cellular defences against infection and cell stress. It is possible that cellular defence pathways can be subverted by viruses to generate sites of replication. The recruitment of cellular membranes and cytoskeleton to generate virus replication sites can also benefit viruses in other ways. Disruption of cellular membranes can, for example, slow the transport of immunomodulatory proteins to the surface of infected cells and protect against innate and acquired immune responses, and rearrangements to cytoskeleton can facilitate virus release.
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Affiliation(s)
- Christopher Netherton
- Vaccinology Group, Pirbright Laboratories, Institute for Animal Health, Surrey, United Kingdom
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16
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Resch W, Hixson KK, Moore RJ, Lipton MS, Moss B. Protein composition of the vaccinia virus mature virion. Virology 2006; 358:233-47. [PMID: 17005230 DOI: 10.1016/j.virol.2006.08.025] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 08/03/2006] [Accepted: 08/18/2006] [Indexed: 10/24/2022]
Abstract
The protein content of vaccinia virus mature virions, purified by rate zonal and isopycnic centrifugations and solubilized by SDS or a solution of urea and thiourea, was determined by the accurate mass and time tag technology which uses both tandem mass spectrometry and Fourier transform-ion cyclotron resonance mass spectrometry to detect tryptic peptides separated by high-resolution liquid chromatography. Eighty vaccinia virus-encoded proteins representing 37% of the 218 genes annotated in the complete genome sequence were detected in at least three analyses. Ten proteins accounted for approximately 80% of the virion mass. Thirteen identified proteins were not previously reported as components of virions. On the other hand, 8 previously described virion proteins were not detected here, presumably due to technical reasons including small size and hydrophobicity. In addition to vaccinia virus-encoded proteins, 24 host proteins omitting isoforms were detected. The most abundant of these were cytoskeletal proteins, heat shock proteins and proteins involved in translation.
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Affiliation(s)
- Wolfgang Resch
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 4 Center Drive, MSC 0445, Bethesda, MD 20892-0445, USA
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17
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Abstract
Poxviruses comprise a large family of viruses characterized by a large, linear dsDNA genome, a cytoplasmic site of replication and a complex virion morphology. The most notorious member of the poxvirus family is variola, the causative agent of smallpox. The laboratory prototype virus used for the study of poxviruses is vaccinia, the virus that was used as a live, naturally attenuated vaccine for the eradication of smallpox. Both the morphogenesis and structure of poxvirus virions are unique among viruses. Poxvirus virions apparently lack any of the symmetry features common to other viruses such as helical or icosahedral capsids or nucleocapsids. Instead poxvirus virions appear as "brick shaped" or "ovoid" membrane-bound particles with a complex internal structure featuring a walled, biconcave core flanked by "lateral bodies." The virion assembly pathway involves a remarkable fabrication of membrane-containing crescents and immature virions, which evolve into mature virions in a process that is unparalleled in virology. As a result of significant advances in poxvirus genetics and molecular biology during the past 15 years, we can now positively identify over 70 specific gene products contained in poxvirus virions, and we can describe the effects of mutations in over 50 specific genes on poxvirus assembly. This review summarizes these advances and attempts to assemble them into a comprehensible and thoughtful picture of poxvirus structure and assembly.
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Affiliation(s)
- Richard C Condit
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, 32610, USA
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18
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Yoder JD, Chen TS, Gagnier CR, Vemulapalli S, Maier CS, Hruby DE. Pox proteomics: mass spectrometry analysis and identification of Vaccinia virion proteins. Virol J 2006; 3:10. [PMID: 16509968 PMCID: PMC1540416 DOI: 10.1186/1743-422x-3-10] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 03/01/2006] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Although many vaccinia virus proteins have been identified and studied in detail, only a few studies have attempted a comprehensive survey of the protein composition of the vaccinia virion. These projects have identified the major proteins of the vaccinia virion, but little has been accomplished to identify the unknown or less abundant proteins. Obtaining a detailed knowledge of the viral proteome of vaccinia virus will be important for advancing our understanding of orthopoxvirus biology, and should facilitate the development of effective antiviral drugs and formulation of vaccines. RESULTS In order to accomplish this task, purified vaccinia virions were fractionated into a soluble protein enriched fraction (membrane proteins and lateral bodies) and an insoluble protein enriched fraction (virion cores). Each of these fractions was subjected to further fractionation by either sodium dodecyl sulfate-polyacrylamide gel electophoresis, or by reverse phase high performance liquid chromatography. The soluble and insoluble fractions were also analyzed directly with no further separation. The samples were prepared for mass spectrometry analysis by digestion with trypsin. Tryptic digests were analyzed by using either a matrix assisted laser desorption ionization time of flight tandem mass spectrometer, a quadrupole ion trap mass spectrometer, or a quadrupole-time of flight mass spectrometer (the latter two instruments were equipped with electrospray ionization sources). Proteins were identified by searching uninterpreted tandem mass spectra against a vaccinia virus protein database created by our lab and a non-redundant protein database. CONCLUSION Sixty three vaccinia proteins were identified in the virion particle. The total number of peptides found for each protein ranged from 1 to 62, and the sequence coverage of the proteins ranged from 8.2% to 94.9%. Interestingly, two vaccinia open reading frames were confirmed as being expressed as novel proteins: E6R and L3L.
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Affiliation(s)
- Jennifer D Yoder
- Oregon State University, Department of Microbiology, 220 Nash Hall, Corvallis, OR 97331-3804, USA
| | - Tsefang S Chen
- Oregon State University, Department of Microbiology, 220 Nash Hall, Corvallis, OR 97331-3804, USA
| | - Cliff R Gagnier
- Oregon State University, Department of Microbiology, 220 Nash Hall, Corvallis, OR 97331-3804, USA
| | - Srilakshmi Vemulapalli
- Oregon State University, Applied Biotechnology Program, 2082 Cordley Hall, Corvallis, OR 97331-8530, USA
| | - Claudia S Maier
- Oregon State University, Department of Chemistry, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA
| | - Dennis E Hruby
- Oregon State University, Department of Microbiology, 220 Nash Hall, Corvallis, OR 97331-3804, USA
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19
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Chung CS, Chen CH, Ho MY, Huang CY, Liao CL, Chang W. Vaccinia virus proteome: identification of proteins in vaccinia virus intracellular mature virion particles. J Virol 2006; 80:2127-40. [PMID: 16474121 PMCID: PMC1395410 DOI: 10.1128/jvi.80.5.2127-2140.2006] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 12/05/2005] [Indexed: 12/17/2022] Open
Abstract
Vaccinia virus is a large enveloped poxvirus with more than 200 genes in its genome. Although many poxvirus genomes have been sequenced, knowledge of the host and viral protein components of the virions remains incomplete. In this study, we used gel-free liquid chromatography and tandem mass spectroscopy to identify the viral and host proteins in purified vaccinia intracellular mature virions (IMV). Analysis of the proteins in the IMV showed that it contains 75 viral proteins, including structural proteins, enzymes, transcription factors, and predicted viral proteins not known to be expressed or present in the IMV. We also determined the relative abundances of the individual protein components in the IMV. Finally, 23 IMV-associated host proteins were also identified. This study provides the first comprehensive structural analysis of the infectious vaccinia virus IMV.
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Affiliation(s)
- Che-Sheng Chung
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
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20
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Chiu WL, Szajner P, Moss B, Chang W. Effects of a temperature sensitivity mutation in the J1R protein component of a complex required for vaccinia virus assembly. J Virol 2005; 79:8046-56. [PMID: 15956550 PMCID: PMC1143739 DOI: 10.1128/jvi.79.13.8046-8056.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Vaccinia virus J1R protein is required for virion morphogenesis (W. L. Chiu and W. Chang, J. Virol. 76:9575-9587, 2002). In this work, we further characterized the J1R protein of wild-type vaccinia virus and compared it with the protein encoded by the temperature-sensitive mutant virus Cts45. The mutant Cts45 was found to contain a Pro-to-Ser substitution at residue 132 of the J1R open reading frame, which is responsible for a loss-of-function phenotype. The half-life of the J1R-P132S mutant protein was comparable at both 31 and 39 degrees C, indicating that the P132S mutation did not affect the stability of the J1R protein. We also showed that the J1R protein interacts with itself in the virus-infected cells. The N-terminal region of the J1R protein, amino acids (aa) 1 to 77, interacted with the C-terminal region, aa 84 to 153, and the P132 mutation did not abolish this interaction, as determined by two-hybrid analysis. Furthermore, we demonstrated that J1R protein is part of a viral complex containing the A30L, G7L, and F10L proteins in virus-infected cells. In immunofluorescence analyses, wild-type J1R protein colocalized with the A30L, G7L, and F10L proteins in virus-infected cells but the loss-of-function P132 mutant did not. Furthermore, without a functional J1R protein, rapid degradation of A30L and the 15-kDa forms of the G7L and F10L proteins was observed in cells infected with Cts45 at 39 degrees C. This study thus demonstrated the importance of the J1R protein in the formation of a viral assembly complex required for morphogenesis.
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Affiliation(s)
- Wen-Ling Chiu
- Institute of Molecular Biology, Academia Sinica, 128, Sec. 2, Academia Road, Nankang, Taipei 11529, Taiwan, Republic of China
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21
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Punjabi A, Traktman P. Cell biological and functional characterization of the vaccinia virus F10 kinase: implications for the mechanism of virion morphogenesis. J Virol 2005; 79:2171-90. [PMID: 15681420 PMCID: PMC546551 DOI: 10.1128/jvi.79.4.2171-2190.2005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The vaccinia virus F10 protein is one of two virally encoded protein kinases. A phenotypic analysis of infections involving a tetracycline-inducible recombinant (vDeltaiF10) indicated that F10 is involved in the early stages of virion morphogenesis, as previously reported for the mutants ts28 and ts15. The proteins encoded by ts28 and ts15 have primary defects in enzymatic activity and thermostability, respectively. Using a transient complementation assay, we demonstrated that the enzymatic activity of F10 is essential for its biological function and that both its enzymatic and biological functions depend upon N-terminal sequences that precede the catalytic domain. An execution point analysis indicated that in addition to its role at the onset of morphogenesis, F10 is also required at later stages, when membrane crescents surround virosomal contents and develop into immature virions. The F10 protein is phosphorylated in vivo, appears to be tightly associated with intracellular membranes, and can bind to specific phosphoinositides in vitro. When F10 is repressed or impaired, the phosphorylation of several cellular and viral proteins appears to increase in intensity, suggesting that F10 may normally intersect with cellular signaling cascades via the activation of a phosphatase or the inhibition of another kinase. These cascades may drive the F10-induced remodeling of membranes that accompanies virion biogenesis. Upon the release of ts28-infected cultures from a 40 degrees C-induced block, a synchronous resumption of morphogenesis that culminates in the production of infectious virus can be observed. The pharmacological agents H89 and cerulenin, which are inhibitors of endoplasmic reticulum exit site formation and de novo lipid synthesis, respectively, block this recovery.
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Affiliation(s)
- Almira Punjabi
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Rd., BSB-273, Milwaukee, WI 53226, USA
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22
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Mercer J, Traktman P. Genetic and cell biological characterization of the vaccinia virus A30 and G7 phosphoproteins. J Virol 2005; 79:7146-61. [PMID: 15890954 PMCID: PMC1112092 DOI: 10.1128/jvi.79.11.7146-7161.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The vaccinia virus proteins A30 and G7 are known to play essential roles in early morphogenesis, acting prior to the formation of immature virions. Their repression or inactivation results in the accumulation of large virosomes, detached membrane crescents, and empty immature virions. We have undertaken further study of these proteins to place them within the context of the F10 kinase, the A14 membrane protein, and the H5 phosphoprotein, which have been the focus of previous studies within our laboratory. Here we confirm that both A30 and G7 undergo F10 kinase-dependent phosphorylation in vivo and recapitulate that modification of A30 in vitro. Although the detached crescents observed upon loss of A30 or G7 echo those seen upon repression of A14, no interaction between A30/G7 and A14 could be detected. We did, however, determine that the A30 and G7 proteins are unstable during nonpermissive tsH5 infections, suggesting that the loss of A30/G7 is the underlying cause for the formation of lacy or curdled virosomes. We also determined that the temperature-sensitive phenotype of the Cts11 virus is due to mutations in two codons of the G7L gene. Phenotypic analysis of nonpermissive Cts11 infections indicated that these amino acid substitutions compromise G7 function without impairing the stability of either G7 or A30. Utilizing Cts11 in conjunction with a rifampin release assay, we determined that G7 acts at multiple stages of virion morphogenesis that can be distinguished both by ultrastructural analysis and by monitoring the phosphorylation status of several viral proteins that undergo F10-mediated phosphorylation.
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Affiliation(s)
- Jason Mercer
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Paula Traktman
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
- Corresponding author. Mailing address: Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Rd., BSB-273, Milwaukee, WI 53226. Phone: (414) 456-8253. Fax: (414) 456-6535. E-mail:
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23
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Resch W, Weisberg AS, Moss B. Vaccinia virus nonstructural protein encoded by the A11R gene is required for formation of the virion membrane. J Virol 2005; 79:6598-609. [PMID: 15890898 PMCID: PMC1112135 DOI: 10.1128/jvi.79.11.6598-6609.2005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The vaccinia virus A11R gene has orthologs in all known poxvirus genomes, and the A11 protein has been previously reported to interact with the putative DNA packaging protein A32 in a yeast two-hybrid screen. Using antisera raised against A11 peptides, we show that the A11 protein was (i) expressed at late times with an apparent mass of 40 kDa, (ii) not incorporated into virus particles, (iii) phosphorylated independently of the viral F10 kinase, (iv) coimmunoprecipitated with A32, and (v) localized to the viral factory. To determine the role of the A11 protein and test whether it is indeed involved in DNA packaging, we constructed a recombinant vaccinia virus with an inducible A11R gene. This recombinant was dependent on inducer for single-cycle growth and plaque formation. In the absence of inducer, viral late proteins were produced at normal levels, but proteolytic processing and other posttranslational modifications of some proteins were inhibited, suggesting a block in virus particle assembly. Consistent with this observation, electron microscopy of cells infected in the absence of inducer showed virus factories with abnormal electron-dense viroplasms and intermediate density regions associated with membranes and containing the D13 protein. However, no viral membrane crescents, immature virions, or mature virions were produced. The requirement for nonvirion protein A11 in order to make normal viral membranes was an unexpected and exciting finding, since neither the origin of these membranes nor their mechanism of formation in the cytoplasm of infected cells is understood.
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Affiliation(s)
- Wolfgang Resch
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0445, USA
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24
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Sainova IV, Kril AI, Simeonov KB, Popova TP, Ivanov IG. Investigation of the morphology of cell clones, derived from the mammalian EBTr cell line and their susceptibility to vaccine avian poxvirus strains FK and Dessau. J Virol Methods 2005; 124:37-40. [PMID: 15664048 DOI: 10.1016/j.jviromet.2004.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Revised: 10/18/2004] [Accepted: 10/19/2004] [Indexed: 11/24/2022]
Abstract
The ability for replication of vaccine avian pox viral strains FK and Dessau in cell clones, derived from the EBTr cell line, derived from embryonic bovine trachea, was studied. The derived seven cell clones showed different morphological characteristics and diverse sensitivity to both vaccine avian pox viral strains. Hence, the EBTr-derived cell clones could be used for cultivation, as well as for differentiation of vaccine avian pox viral strains. In addition, studies have been undertaken to elucidate the possible use of cultivated strains in these heterologous cell culture system's vaccine avian pox viral strains for biotechnology, as well as for solving problems, related to infection of people with avian viruses.
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Affiliation(s)
- Iskra Ventseslavova Sainova
- Bulgarian Academy of Sciences, Central Laboratory of Optical Storage and Processing of Information, Acad. Georgi Bonchev Street, Block 101, P.O. Box 95, 1113 Sofia, Bulgaria.
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25
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Szajner P, Jaffe H, Weisberg AS, Moss B. A complex of seven vaccinia virus proteins conserved in all chordopoxviruses is required for the association of membranes and viroplasm to form immature virions. Virology 2005; 330:447-59. [PMID: 15567438 DOI: 10.1016/j.virol.2004.10.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Revised: 09/28/2004] [Accepted: 10/05/2004] [Indexed: 10/26/2022]
Abstract
Early events in vaccinia virus (VAC) morphogenesis, particularly the formation of viral membranes and their association with viroplasm, are poorly understood. Recently, we showed that repression of A30 or G7 expression results in the accumulation of normal viral membranes that form empty-looking immature virions (IV), which are separated from large masses of electron-dense viroplasm. In addition, A30 and G7 physically and functionally interact with each other and with the F10 protein kinase. To identify other proteins involved in early morphogenesis, proteins from cells that had been infected with vaccinia virus expressing an epitope-tagged copy of F10 were purified by immunoaffinity chromatography and analyzed by gel electrophoresis. In addition to F10, A30, and G7, viral proteins A15, D2, D3, and J1 were identified by mass spectrometry of tryptic peptides. Further evidence for the complex was obtained by immunopurification of proteins associated with epitope-tagged A15, D2, and D3. The previously unstudied A15, like other proteins in the complex, was expressed late in infection, associated with virus cores, and required for the stability and kinase activity of F10. Biochemical and electron microscopic analyses indicated that mutants in which A15 or D2 expression was regulated by the Escherichia coli lac operator system exhibited phenotypes characterized by the presence of large numbers of empty immature virions, similar to the results obtained with inducible A30 and G7 mutants. Empty immature virions were also seen by electron microscopy of cells infected with temperature-sensitive mutants of D2 or D3, though the numbers of membrane forms were reduced perhaps due to additional effects of high temperature.
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Affiliation(s)
- Patricia Szajner
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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26
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da Fonseca FG, Weisberg AS, Caeiro MF, Moss B. Vaccinia virus mutants with alanine substitutions in the conserved G5R gene fail to initiate morphogenesis at the nonpermissive temperature. J Virol 2004; 78:10238-48. [PMID: 15367589 PMCID: PMC516429 DOI: 10.1128/jvi.78.19.10238-10248.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The initial characterization of the product of the vaccinia virus G5R gene, which is conserved in all poxviruses sequenced to date, is described. The G5 protein was detected in the core fraction of purified virions, and transcription and translation of the G5R open reading frame occurred early in infection, independently of DNA replication. Attempts to delete the G5R gene and isolate a replication-competent virus were unsuccessful, suggesting that G5R encodes an essential function. We engineered vaccinia virus mutants with clusters of charged amino acids changed to alanines and determined that several were unable to replicate at 40 degrees C but grew well at 37 degrees C. At the nonpermissive temperature, viral gene expression and DNA replication and processing were unperturbed. However, tyrosine phosphorylation and proteolytic cleavage of the A17 membrane protein and proteolytic cleavage of core proteins were inhibited at 40 degrees C, suggesting an assembly defect. The cytoplasm of cells that had been infected at the nonpermissive temperature contained large granular areas devoid of cellular organelles or virus structures except for occasional short crescent-shaped membranes and electron-dense lacy structures. The temperature-sensitive phenotype of the G5R mutants closely resembled the phenotypes of vaccinia virus mutants carrying conditionally lethal F10R protein kinase and H5R mutations. F10, although required for phosphorylation of A17 and viral membrane formation, was synthesized by the G5R mutants under nonpermissive conditions. An intriguing possibility is that G5 participates in the formation of viral membranes, a poorly understood event in poxvirus assembly.
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Affiliation(s)
- Flavio G da Fonseca
- Laboratory of Viral Diseases, National Institutes of Health, 4 Center Dr., MSC 0445, Bethesda, MD 20892-0445, USA
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27
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Szajner P, Weisberg AS, Moss B. Evidence for an essential catalytic role of the F10 protein kinase in vaccinia virus morphogenesis. J Virol 2004; 78:257-65. [PMID: 14671107 PMCID: PMC303407 DOI: 10.1128/jvi.78.1.257-265.2004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Temperature-sensitive mutants of vaccinia virus, with genetic changes that map to the open reading frame encoding the F10 protein kinase, exhibit a defect at an early stage of viral morphogenesis. To further study the role of the enzyme, we constructed recombinant vaccinia virus vF10V5i, which expresses inducible V5 epitope-tagged F10 and is dependent on a chemical inducer for plaque formation and replication. In the absence of inducer, viral membrane formation was delayed and crescents and occasional immature forms were detected only late in infection. When the temperature was raised from 37 to 39 degrees C, the block in membrane formation persisted throughout the infection. The increased stringency may be explained by a mild temperature sensitivity of the wild-type F10 kinase, which reduced the activity of the very small amount expressed in the absence of inducer, or by the thermolability of an unphosphorylated kinase substrate or uncomplexed F10-interacting protein. Further analyses demonstrated that tyrosine and threonine phosphorylation of the A17 membrane component was inhibited in the absence of inducer. The phosphorylation defect could be overcome by transfection of plasmids that express wild-type F10, but not by plasmids that express F10 with single amino acid substitutions that abolished catalytic activity. Although the mutated forms of F10 were stable and concentrated in viral factories, only the wild-type protein complemented the assembly and replication defects of vF10V5i in the absence of inducer. These studies provide evidence for an essential catalytic role of the F10 kinase in vaccinia virus morphogenesis.
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Affiliation(s)
- Patricia Szajner
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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28
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Szajner P, Weisberg AS, Moss B. Physical and functional interactions between vaccinia virus F10 protein kinase and virion assembly proteins A30 and G7. J Virol 2004; 78:266-74. [PMID: 14671108 PMCID: PMC303406 DOI: 10.1128/jvi.78.1.266-274.2004] [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] [Received: 07/16/2003] [Accepted: 09/12/2003] [Indexed: 11/20/2022] Open
Abstract
An early step in vaccinia virus morphogenesis, the association of crescent membranes with electron-dense granular material, is perturbed when expression of the viral protein encoded by the A30L or G7L open reading frame is repressed. Under these conditions, we found that phosphorylation of the A17 membrane protein, which is mediated by the F10 kinase, was severely reduced. Furthermore, A30 and G7 stimulated F10-dependent phosphorylation of A17 in the absence of other viral late proteins. Evidence for physical interactions between A30, G7, and F10 was obtained by their coimmunoprecipitation with antibody against A30 or F10. In addition, phosphorylation of A30 was dependent on the F10 kinase and autophosphorylation of F10 was stimulated by A30 and G7. Nevertheless, the association of A30, G7, and F10 occurred even with mutated, catalytically inactive forms of F10. Just as A30 and G7 are mutually dependent on each other for stability, F10 was nearly undetectable in the absence of A30 and G7. The reverse is not true, however, as repression of F10 did not diminish A30 or G7. Interaction of F10 with A30 and G7 presumably occurred within the virus factory areas of the cytoplasm, where each was concentrated. F10 localized predominantly in the cortical region of immature virions, beneath the membrane where A17 is located. F10 remained associated with the particulate core fraction of mature virions after treatment with a nonionic detergent and reducing agent. The formation of protein complexes such as the one involving A30, G7, and F10 may be a mechanism for the regulated packaging and processing of virion components.
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Affiliation(s)
- Patricia Szajner
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Castro APV, Carvalho TMU, Moussatché N, Damaso CRA. Redistribution of cyclophilin A to viral factories during vaccinia virus infection and its incorporation into mature particles. J Virol 2003; 77:9052-68. [PMID: 12885921 PMCID: PMC167230 DOI: 10.1128/jvi.77.16.9052-9068.2003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Accepted: 05/28/2003] [Indexed: 11/20/2022] Open
Abstract
Cyclophilins are peptidyl-prolyl cis-trans isomerases involved in catalyzing conformational changes and accelerating the rate of protein folding and refolding in several cellular systems. In the present study, we analyzed the expression pattern and intracellular distribution of the cellular isomerase cyclophilin A (CypA) during vaccinia virus (VV) infection. An impressive increase in CypA stability was observed, leading to a practically unchanged accumulation of CypA during infection, although its synthesis was completely inhibited at late times. By confocal microscopy, we observed that CypA went through an intense reorganization in the cell cytoplasm and colocalized with the virosomes late in infection. CypA relocation to viral factories required the synthesis of viral postreplicative proteins, and treatment of infected cells with cyclosporine (CsA) prevented CypA relocation, clearly excluding the virosomes from CypA staining. Immunoelectron microscopy of VV-infected cells showed that CypA was incorporated into VV particles during morphogenesis. Biochemical and electron microscopic assays with purified virions confirmed that CypA was encapsidated within the virus particle and localized specifically in the core. This work suggests that CypA may develop an important role in VV replication.
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Affiliation(s)
- Ana Paula V Castro
- Laboratório de Biologia Molecular de Vírus, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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Szajner P, Jaffe H, Weisberg AS, Moss B. Vaccinia virus G7L protein Interacts with the A30L protein and is required for association of viral membranes with dense viroplasm to form immature virions. J Virol 2003; 77:3418-29. [PMID: 12610117 PMCID: PMC149536 DOI: 10.1128/jvi.77.6.3418-3429.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The vaccinia virus A30L protein is required for the association of electron-dense, granular, proteinaceous material with the concave surfaces of crescent membranes, an early step in viral morphogenesis. For the identification of additional proteins involved in this process, we used an antibody to the A30L protein, or to an epitope appended to its C terminus, to capture complexes from infected cells. A prominent 42-kDa protein was resolved and identified by mass spectrometry as the vaccinia virus G7L protein. This previously uncharacterized protein was expressed late in infection and was associated with immature virions and the cores of mature particles. In order to study the role of the G7L protein, a conditional lethal mutant was made by replacing the G7L gene with an inducible copy. Expression of G7L and formation of infectious virus was dependent on the addition of inducer. Under nonpermissive conditions, morphogenesis was blocked and viral crescent membranes and immature virions containing tubular elements were separated from the electron-dense granular viroplasm, which accumulated in large spherical masses. This phenotype was identical to that previously obtained with an inducible, conditional lethal A30L mutant. Additional in vivo and in vitro experiments provided evidence for the direct interaction of the A30L and G7L proteins and demonstrated that the stability of each one was dependent on its association with the other.
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Affiliation(s)
- Patricia Szajner
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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31
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Chiu WL, Chang W. Vaccinia virus J1R protein: a viral membrane protein that is essential for virion morphogenesis. J Virol 2002; 76:9575-87. [PMID: 12208937 PMCID: PMC136503 DOI: 10.1128/jvi.76.19.9575-9587.2002] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vaccinia virus, a member of the poxvirus family, contains a conserved J1R open reading frame that encodes a late protein of 17.8 kDa. The 18-kDa J1R protein is associated mainly with the membrane fraction of intracellular mature virus particles. This study examines the biological function of J1R protein in the vaccinia virus life cycle. A recombinant vaccinia virus was constructed to conditionally express J1R protein in an isopropyl-beta-D-galactopyranoside (IPTG)-inducible manner. When J1R is not expressed during vaccinia virus infection, the virus titer is reduced approximately 100-fold. In contrast, J1R protein is not required for viral gene expression, as indicated by protein pulse-labeling. J1R protein is also not required for DNA processing, as the resolution of the concatemer junctions of replicated viral DNA was detected without IPTG. A deficiency of J1R protein caused a severe delay in the processing of p4a and p4b into mature core proteins 4a and 4b, indicating that J1R protein participates in virion morphogenesis. Infected cells grown in the absence of IPTG contained very few intracellular mature virions in the cytoplasm, and enlarged viroplasm structures accumulated with viral crescents attached at the periphery. Abundant intermediate membrane structures of abnormal shapes were observed, and many immature virions were either empty or partially filled, indicating that J1R protein is important for DNA packaging into immature virions. J1R protein also coimmunoprecipited with A45R protein in infected cells. In summary, these results indicate that vaccinia virus J1R is a membrane protein that is required for virus growth and plaque formation. J1R protein interacts with A45R protein and performs an important role during immature virion formation in cultured cells.
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Affiliation(s)
- Wen-Ling Chiu
- Graduate Institute of Life Science, National Defense Medical Center. Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China
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Damaso CRA, Oliveira MF, Massarani SM, Moussatché N. Azathioprine inhibits vaccinia virus replication in both BSC-40 and RAG cell lines acting on different stages of virus cycle. Virology 2002; 300:79-91. [PMID: 12202208 DOI: 10.1006/viro.2002.1534] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In the present study we demonstrate that azathioprine (AZA) inhibits vaccinia virus (VV) replication in both BSC-40 and RAG cell lines, acting on different stages of virus cycle. In BSC-40 cells, early protein synthesis was not significantly affected, but late gene expression was severely impaired. In RAG cells all stages of gene expression were completed during synchronous infection in the presence of the drug. The onset of DNA replication was not affected in RAG cells, but a severe inhibition was observed in BSC-40 cells. Electron microscopic analysis of VV-infected RAG cells treated with AZA revealed brick-shaped particles presenting abnormal definition of the internal structure. Purified virions from AZA-treated RAG cells presented several modifications of the protein content, a lesser amount of DNA, and a lower PFU:particle ratio. Our results suggest that in VV-infected RAG cells AZA interfered with virus morphogenesis, whereas in BSC-40 cells the replicative cycle was inhibited at the DNA replication stage.
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Affiliation(s)
- Clarissa R A Damaso
- Laboratório de Biologia Molecular de Vi;rus, Instituto de Biofi;sica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, Brazil
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33
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Cao JX, McFadden G. Characterization of the myxoma virus M118L protein: a novel essential poxvirus IMV-associated protein. Virus Genes 2001; 23:303-13. [PMID: 11778698 DOI: 10.1023/a:1012573306916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Myxoma M118L ORF has the capacity to encode a 76 amino acid protein that is highly conserved in other vertebrate poxviruses including vaccinia (A30L), molluscum contagiosum (MC136L), yaba tumour virus (D13L) and fowlpox virus (FPV 194). The time course analysis by Western blotting using M118L antibody showed that the M118L ORF is expressed as a typical poxvirus late gene. The M118L protein can be detected in both the virus infected cytosolic and membrane fractions, even though the M118L protein does not possess a predicted transmembrane domain. The protein was found to be associated with the sucrose gradient purified myxoma intracellular mature virus (IMV) as determined by Western blotting with M118L antibody. Furthermore, the M118L protein associated with the IMV can be surface labeled with water-soluble biotin and is released from the purified IMV with treatment of nonionic detergent NP-40, indicating that the M118L protein is associated with the outer membrane of myxoma IMV. Unexpectedly, an IMV-associated M118L protein isoform was observed to bind tightly to Streptavidin beads, unlike the six other detectable myxoma IMV surface proteins, suggesting an unusual post-translational modification, such as biotinylation. Extensive attempts to generate the M118L deletion mutant using standard homologous recombination technique with E. coli gpt gene as a positive selection marker were unsuccessful. Although PCR analysis clearly indicated the presence of the correctly targeted M118L deletion mutants in mixed recombinant virus plaques selected with mycophenolic acid (MPA), repeated passages and plaquing failed to segregate the pure M118L deletion mutant from either single crossover recombinants or regenerated wild type parental viruses. Taken together, our data strongly indicate that the M118L is a novel poxvirus IMV associated protein that is essential for virus viability.
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Affiliation(s)
- J X Cao
- The John P. Robarts Research Institute, London, Ontario, Canada
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Szajner P, Weisberg AS, Moss B. Unique temperature-sensitive defect in vaccinia virus morphogenesis maps to a single nucleotide substitution in the A30L gene. J Virol 2001; 75:11222-6. [PMID: 11602762 PMCID: PMC114702 DOI: 10.1128/jvi.75.22.11222-11226.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Marker rescue experiments demonstrated that the genetic lesion of a previously isolated vaccinia virus temperature-sensitive mutant which forms multilayered envelope structures with lucent interiors and foci of viroplasm with dense centers mapped to the A30L open reading frame. A single base change, resulting in a nonconservative Ser-to-Phe substitution at residue 17, was associated with degradation of the A30L protein at elevated temperatures.
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Affiliation(s)
- P Szajner
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0445, USA
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