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Sami SA, Marma KKS, Mahmud S, Khan MAN, Albogami S, El-Shehawi AM, Rakib A, Chakraborty A, Mohiuddin M, Dhama K, Uddin MMN, Hossain MK, Tallei TE, Emran TB. Designing of a Multi-epitope Vaccine against the Structural Proteins of Marburg Virus Exploiting the Immunoinformatics Approach. ACS OMEGA 2021; 6:32043-32071. [PMID: 34870027 PMCID: PMC8638006 DOI: 10.1021/acsomega.1c04817] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/10/2021] [Indexed: 05/08/2023]
Abstract
Marburg virus disease (MVD) caused by the Marburg virus (MARV) generally appears with flu-like symptoms and leads to severe hemorrhagic fever. It spreads via direct contact with infected individuals or animals. Despite being considered to be less threatening in terms of appearances and the number of infected patients, the high fatality rate of this pathogenic virus is a major concern. Until now, no vaccine has been developed to combat this deadly virus. Therefore, vaccination for this virus is necessary to reduce its mortality. Our current investigation focuses on the design and formulation of a multi-epitope vaccine based on the structural proteins of MARV employing immunoinformatics approaches. The screening of potential T-cell and B-cell epitopes from the seven structural proteins of MARV was carried out through specific selection parameters. Afterward, we compiled the shortlisted epitopes by attaching them to an appropriate adjuvant and linkers. Population coverage analysis, conservancy analysis, and MHC cluster analysis of the shortlisted epitopes were satisfactory. Importantly, physicochemical characteristics, human homology assessment, and structure validation of the vaccine construct delineated convenient outcomes. We implemented disulfide bond engineering to stabilize the tertiary or quaternary interactions. Furthermore, stability and physical movements of the vaccine protein were explored using normal-mode analysis. The immune simulation study of the vaccine complexes also exhibited significant results. Additionally, the protein-protein docking and molecular dynamics simulation of the final construct exhibited a higher affinity toward toll-like receptor-4 (TLR4). From simulation trajectories, multiple descriptors, namely, root mean square deviations (rmsd), radius of gyration (Rg), root mean square fluctuations (RMSF), solvent-accessible surface area (SASA), and hydrogen bonds, have been taken into account to demonstrate the inflexible and rigid nature of receptor molecules and the constructed vaccine. Inclusively, our findings suggested the vaccine constructs' ability to regulate promising immune responses against MARV pathogenesis.
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Affiliation(s)
- Saad Ahmed Sami
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Kay Kay Shain Marma
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Shafi Mahmud
- Microbiology
Laboratory, Bioinformatics Division, Department of Genetic Engineering
and Biotechnology, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Md. Asif Nadim Khan
- Department of Biochemistry and Molecular
Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong 4331, Bangladesh
| | - Sarah Albogami
- Department
of Biotechnology, College of Science, Taif
University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Ahmed M. El-Shehawi
- Department
of Biotechnology, College of Science, Taif
University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Ahmed Rakib
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Agnila Chakraborty
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Mostafah Mohiuddin
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary
Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243122, India
| | - Mir Muhammad Nasir Uddin
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Mohammed Kamrul Hossain
- Department of Pharmacy,
Faculty of Biological Sciences, University
of Chittagong, Chittagong 4331, Bangladesh
| | - Trina Ekawati Tallei
- Department of Biology,
Faculty of Mathematics and Natural Sciences, Sam Ratulangi University, Manado, North Sulawesi 95115, Indonesia
| | - Talha Bin Emran
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong 4381, Bangladesh
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2
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Ilinykh PA, Huang K, Santos RI, Gilchuk P, Gunn BM, Karim MM, Liang J, Fouch ME, Davidson E, Parekh DV, Kimble JB, Pietzsch CA, Meyer M, Kuzmina NA, Zeitlin L, Saphire EO, Alter G, Crowe JE, Bukreyev A. Non-neutralizing Antibodies from a Marburg Infection Survivor Mediate Protection by Fc-Effector Functions and by Enhancing Efficacy of Other Antibodies. Cell Host Microbe 2020; 27:976-991.e11. [PMID: 32320678 DOI: 10.1016/j.chom.2020.03.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 12/10/2019] [Accepted: 03/26/2020] [Indexed: 11/15/2022]
Abstract
Marburg virus (MARV) and Ebola virus (EBOV) belong to the family Filoviridae. MARV causes severe disease in humans with high fatality. We previously isolated a large panel of monoclonal antibodies (mAbs) from B cells of a human survivor with previous naturally acquired MARV infection. Here, we characterized functional properties of these mAbs and identified non-neutralizing mAbs targeting the glycoprotein (GP) 2 portion of the mucin-like domain (MLD) of MARV GP, termed the wing region. One mAb targeting the GP2 wing, MR228, showed therapeutic protection in mice and guinea pigs infected with MARV. The protection was mediated by the Fc fragment functions of MR228. Binding of another GP2 wing-specific non-neutralizing mAb, MR235, to MARV GP increased accessibility of epitopes in the receptor-binding site (RBS) for neutralizing mAbs, resulting in enhanced virus neutralization by these mAbs. These findings highlight an important role for non-neutralizing mAbs during natural human MARV infection.
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Affiliation(s)
- Philipp A Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Rodrigo I Santos
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bronwyn M Gunn
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - Marcus M Karim
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - Jenny Liang
- Integral Molecular, Philadelphia, PA 19104, USA
| | | | | | - Diptiben V Parekh
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - James B Kimble
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Colette A Pietzsch
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Michelle Meyer
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Natalia A Kuzmina
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | | | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - James E Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pediatrics (Infectious Diseases), Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX; Galveston National Laboratory, Galveston, TX, USA.
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3
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Hasan M, Azim KF, Begum A, Khan NA, Shammi TS, Imran AS, Chowdhury IM, Urme SRA. Vaccinomics strategy for developing a unique multi-epitope monovalent vaccine against Marburg marburgvirus. INFECTION GENETICS AND EVOLUTION 2019; 70:140-157. [DOI: 10.1016/j.meegid.2019.03.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/09/2019] [Accepted: 03/04/2019] [Indexed: 12/23/2022]
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4
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Alfson KJ, Avena LE, Delgado J, Beadles MW, Patterson JL, Carrion R, Griffiths A. A Single Amino Acid Change in the Marburg Virus Glycoprotein Arises during Serial Cell Culture Passages and Attenuates the Virus in a Macaque Model of Disease. mSphere 2018; 3:e00401-17. [PMID: 29299527 PMCID: PMC5750385 DOI: 10.1128/msphere.00401-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/04/2017] [Indexed: 12/17/2022] Open
Abstract
Marburg virus (MARV) causes disease with high case fatality rates, and there are no approved vaccines or therapies. Licensing of MARV countermeasures will likely require approval via the FDA's Animal Efficacy Rule, which requires well-characterized animal models that recapitulate human disease. This includes selection of the virus used for exposure and ensuring that it retains the properties of the original isolate. The consequences of amplification of MARV for challenge studies are unknown. Here, we serially passaged and characterized MARV through 13 passes from the original isolate. Surprisingly, the viral genome was very stable, except for a single nucleotide change that resulted in an amino acid substitution in the hydrophobic region of the signal peptide of the glycoprotein (GP). The particle/PFU ratio also decreased following passages, suggesting a role for the amino acid in viral infectivity. To determine if amplification introduces a phenotype in an animal model, cynomolgus macaques were exposed to either 100 or 0.01 PFU of low- and high-passage-number MARV. All animals succumbed when exposed to 100 PFU of either passage 3 or 13 viruses, although animals exposed to the high-passage-number virus survived longer. However, none of the passage 13 MARV-exposed animals succumbed to 0.01-PFU exposure compared to 75% of passage 3-exposed animals. This is consistent with other filovirus studies that show some particles that are unable to yield a plaque in cell culture can cause lethal disease in vivo. These results have important consequences for the design of experiments that investigate MARV pathogenesis and that test the efficacy of MARV countermeasures. IMPORTANCE Marburg virus (MARV) causes disease with a high case fatality rate, and there are no approved vaccines or therapies. Serial amplification of viruses in cell culture often results in accumulation of mutations, but the effect of such cell culture passage on MARV is unclear. Serial passages of MARV resulted in a single mutation in the region encoding the glycoprotein (GP). This is a region where mutations can have important consequences on outbreaks and human disease [S. Mahanty and M. Bray, Lancet Infect Dis 4:487-498, 2004, https://doi.org/10.1016/S1473-3099(04)01103-X]. We thus investigated whether this mutation impacted disease by using a cynomolgus macaque model of MARV infection. Monkeys exposed to virus containing the mutation had better clinical outcomes than monkeys exposed to virus without the mutation. We also observed that a remarkably low number of MARV particles was sufficient to cause death. Our results could have a significant impact on how future studies are designed to model MARV disease and test vaccines and therapeutics.
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Affiliation(s)
- Kendra J. Alfson
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
- University of Texas Health Science Center, San Antonio, Texas, USA
| | - Laura E. Avena
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Jenny Delgado
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Michael W. Beadles
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Jean L. Patterson
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Ricardo Carrion
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Anthony Griffiths
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, USA
- University of Texas Health Science Center, San Antonio, Texas, USA
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5
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Groseth A, Hoenen T. Forty Years of Ebolavirus Molecular Biology: Understanding a Novel Disease Agent Through the Development and Application of New Technologies. Methods Mol Biol 2017; 1628:15-38. [PMID: 28573608 DOI: 10.1007/978-1-4939-7116-9_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Molecular biology is a broad discipline that seeks to understand biological phenomena at a molecular level, and achieves this through the study of DNA, RNA, proteins, and/or other macromolecules (e.g., those involved in the modification of these substrates). Consequently, it relies on the availability of a wide variety of methods that deal with the collection, preservation, inactivation, separation, manipulation, imaging, and analysis of these molecules. As such the state of the art in the field of ebolavirus molecular biology research (and that of all other viruses) is largely intertwined with, if not driven by, advancements in the technical methodologies available for these kinds of studies. Here we review of the current state of our knowledge regarding ebolavirus biology and emphasize the associated methods that made these discoveries possible.
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Affiliation(s)
- Allison Groseth
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Thomas Hoenen
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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6
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Rivera A, Messaoudi I. Molecular mechanisms of Ebola pathogenesis. J Leukoc Biol 2016; 100:889-904. [PMID: 27587404 PMCID: PMC6608070 DOI: 10.1189/jlb.4ri0316-099rr] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
Ebola viruses (EBOVs) and Marburg viruses (MARVs) are among the deadliest human viruses, as highlighted by the recent and widespread Ebola virus outbreak in West Africa, which was the largest and longest epidemic of Ebola virus disease (EVD) in history, resulting in significant loss of life and disruptions across multiple continents. Although the number of cases has nearly reached its nadir, a recent cluster of 5 cases in Guinea on March 17, 2016, has extended the enhanced surveillance period to June 15, 2016. New, enhanced 90-d surveillance windows replaced the 42-d surveillance window to ensure the rapid detection of new cases that may arise from a missed transmission chain, reintroduction from an animal reservoir, or more important, reemergence of the virus that has persisted in an EVD survivor. In this review, we summarize our current understanding of EBOV pathogenesis, describe vaccine and therapeutic candidates in clinical trials, and discuss mechanisms of viral persistence and long-term health sequelae for EVD survivors.
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Affiliation(s)
- Andrea Rivera
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California, USA
| | - Ilhem Messaoudi
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California, USA
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7
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Chimeric Filoviruses for Identification and Characterization of Monoclonal Antibodies. J Virol 2016; 90:3890-3901. [PMID: 26819310 DOI: 10.1128/jvi.00101-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 01/22/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Recent experiments suggest that some glycoprotein (GP)-specific monoclonal antibodies (MAbs) can protect experimental animals against the filovirus Ebola virus (EBOV). There is a need for isolation of MAbs capable of neutralizing multiple filoviruses. Antibody neutralization assays for filoviruses frequently use surrogate systems such as the rhabdovirus vesicular stomatitis Indiana virus (VSV), lentiviruses or gammaretroviruses with their envelope proteins replaced with EBOV GP or pseudotyped with EBOV GP. It is optimal for both screening and in-depth characterization of newly identified neutralizing MAbs to generate recombinant filoviruses that express a reporter fluorescent protein in order to more easily monitor and quantify the infection. Our study showed that unlike neutralization-sensitive chimeric VSV, authentic filoviruses are highly resistant to neutralization by MAbs. We used reverse genetics techniques to replace EBOV GP with its counterpart from the heterologous filoviruses Bundibugyo virus (BDBV), Sudan virus, and even Marburg virus and Lloviu virus, which belong to the heterologous genera in the filovirus family. This work resulted in generation of multiple chimeric filoviruses, demonstrating the ability of filoviruses to tolerate swapping of the envelope protein. The sensitivity of chimeric filoviruses to neutralizing MAbs was similar to that of authentic biologically derived filoviruses with the same GP. Moreover, disabling the expression of the secreted GP (sGP) resulted in an increased susceptibility of an engineered virus to the BDBV52 MAb isolated from a BDBV survivor, suggesting a role for sGP in evasion of antibody neutralization in the context of a human filovirus infection. IMPORTANCE The study demonstrated that chimeric rhabdoviruses in which G protein is replaced with filovirus GP, widely used as surrogate targets for characterization of filovirus neutralizing antibodies, do not accurately predict the ability of antibodies to neutralize authentic filoviruses, which appeared to be resistant to neutralization. However, a recombinant EBOV expressing a fluorescent protein tolerated swapping of GP with counterparts from heterologous filoviruses, allowing high-throughput screening of B cell lines to isolate MAbs of any filovirus specificity. Human MAb BDBV52, which was isolated from a survivor of BDBV infection, was capable of partially neutralizing a chimeric EBOV carrying BDBV GP in which expression of sGP was disabled. In contrast, the parental virus expressing sGP was resistant to the MAb. Thus, the ability of filoviruses to tolerate swapping of GP can be used for identification of neutralizing MAbs specific to any filovirus and for the characterization of MAb specificity and mechanism of action.
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8
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Page A, Volchkova V, Reid S, Mateo M, Bagnaud-Baule A, Nemirov K, Shurtleff A, Lawrence P, Reynard O, Ottmann M, Lotteau V, Biswal S, Thimmulappa R, Bavari S, Volchkov V. Marburgvirus Hijacks Nrf2-Dependent Pathway by Targeting Nrf2-Negative Regulator Keap1. Cell Rep 2014; 6:1026-1036. [DOI: 10.1016/j.celrep.2014.02.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/13/2013] [Accepted: 02/18/2014] [Indexed: 12/26/2022] Open
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9
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Song J, Wolinsky M, Wren M, Burr T, Li PE, Doggett N. Forensic signatures for Marburgviruses. Forensic Sci Int 2013; 233:338-47. [PMID: 24314539 DOI: 10.1016/j.forsciint.2013.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 09/30/2013] [Indexed: 11/30/2022]
Abstract
Marburgvirus is one of the most important hemorrhagic fever viruses with extremely high infectivity and fatality rate (~90%). It is transmitted easily in human populations through a respiratory route and therefore considered as a major biothreat agent. Although detection assays have been developed, no assay is available for forensic analysis. Here we report development of forensic assays for Marburgvirus. We performed detailed phylogenetic analysis of strains and isolates from all known Marburg virus outbreaks as well as from several laboratory strains and identified canonical SNPs for all major clades (outbreaks) and strains. TaqMan-MGB allelic discrimination assays targeting these SNPs were designed and experimentally screened against synthetic RNA templates and genomic RNAs. A total of 45 assays were validated to provide 100% coverage of the clades (outbreaks) and 91% at the strain level (21 out of the 23 targeted Marburgvirus strains) with built-in redundancy for increased robustness. Using these validated assays, we were able to provide accurate forensic analysis on 3 "unknown" Marburgviruses. These high-resolution forensic assays allow rapid and accurate genotyping of Marburgviruses for forensic investigations.
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Affiliation(s)
- Jian Song
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, United States
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10
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Bhattacharyya S, Mulherkar N, Chandran K. Endocytic pathways involved in filovirus entry: advances, implications and future directions. Viruses 2013; 4:3647-64. [PMID: 23342373 PMCID: PMC3528284 DOI: 10.3390/v4123647] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Detailed knowledge of the host-virus interactions that accompany filovirus entry into cells is expected to identify determinants of viral virulence and host range, and to yield targets for the development of antiviral therapeutics. While it is generally agreed that filovirus entry into the host cytoplasm requires viral internalization into acidic endosomal compartments and proteolytic cleavage of the envelope glycoprotein by endo/lysosomal cysteine proteases, our understanding of the specific endocytic pathways co-opted by filoviruses remains limited. This review addresses the current knowledge on cellular endocytic pathways implicated in filovirus entry, highlights the consensus as well as controversies, and discusses important remaining questions.
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Affiliation(s)
- Suchita Bhattacharyya
- Department of Atomic Energy-Centre for Excellence in Basic Sciences, University of Mumbai, Health Centre Building, Vidyanagari, Kalina, Santacruz East, Mumbai 400098, India; E-Mail:
| | - Nirupama Mulherkar
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA; E-Mail:
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-718-430-8851
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11
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Cellular factors implicated in filovirus entry. Adv Virol 2013; 2013:487585. [PMID: 23365575 PMCID: PMC3556833 DOI: 10.1155/2013/487585] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 12/11/2022] Open
Abstract
Although filoviral infections are still occurring in different parts of the world, there are no effective preventive or treatment strategies currently available against them. Not only do filoviruses cause a deadly infection, but they also have the potential of being used as biological weapons. This makes it imperative to comprehensively study these viruses in order to devise effective strategies to prevent the occurrence of these infections. Entry is the foremost step in the filoviral replication cycle and different studies have reported the involvement of a myriad of cellular factors including plasma membrane components, cytoskeletal proteins, endosomal components, and cytosolic factors in this process. Signaling molecules such as the TAM family of receptor tyrosine kinases comprising of Tyro3, Axl, and Mer have also been implicated as putative entry factors. Additionally, filoviruses are suggested to bind to a common receptor and recent studies have proposed T-cell immunoglobulin and mucin domain 1 (TIM-1) and Niemann-Pick C1 (NPC1) as potential receptor candidates. This paper summarizes the existing literature on filoviral entry with a special focus on cellular factors involved in this process and also highlights some fundamental questions. Future research aimed at answering these questions could be very useful in designing novel antiviral therapeutics.
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12
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Mittler E, Kolesnikova L, Herwig A, Dolnik O, Becker S. Assembly of the Marburg virus envelope. Cell Microbiol 2012. [PMID: 23186212 DOI: 10.1111/cmi.12076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The key player to assemble the filamentous Marburg virus particles is the matrix protein VP40 which orchestrates recruitment of nucleocapsid complexes and the viral glycoprotein GP to the budding sites at the plasma membrane. Here, VP40 induces the formation of the viral particles, determines their morphology and excludes cellular proteins from the virions. Budding takes place at filopodia in non-polarized cells and at the basolateral cell pole in polarized epithelial cells. Molecular basis of how VP40 exerts its multifunctional role in these different processes is currently under investigation. Here we summarize recent data on structure-function relationships of VP40 and GP in connection with their function in assembly. Questions concerning the complex particle assembly, budding and release remaining enigmatic are addressed. Cytoplasmic domains of viral surface proteins often serve as a connection to the viral matrix protein or as binding sites for further viral or cellular proteins. A cooperation of MARV GP and VP40 building up the viral envelope can be proposed and is discussed in more detail in this review, as the cytoplasmic domain of GP represents an obvious interaction candidate because of its localization adjacent to the VP40 layer. Interestingly, truncation of the short cytoplasmic domain of GP neither inhibited interaction with VP40 nor incorporation of GP into progeny viral particles. Based on reverse genetics we generated recombinant virions expressing a GP mutant without the cytoplasmic tail. Investigations revealed attenuation in virus growth and an obvious defect in entry. Further investigations showed that the truncation of the cytoplasmic domain of GP impaired the structural integrity of the ectodomain, whichconsequently had impact on entry steps downstream of virus binding. Our data indicated that changes in the cytoplasmic domain are relayed over the lipid membrane to alter the function of the ectodomain.
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Affiliation(s)
- Eva Mittler
- Institute of Virology, Philipps University Marburg, Hans-Meerwein-Strasse 2, 35043 Marburg, Germany
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13
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Abstract
In 1967, the first reported filovirus hemorrhagic fever outbreak took place in Germany and the former Yugoslavia. The causative agent that was identified during this outbreak, Marburg virus, is one of the most deadly human pathogens. This article provides a comprehensive overview of our current knowledge about Marburg virus disease ranging from ecology to pathogenesis and molecular biology.
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Affiliation(s)
- Kristina Brauburger
- Department of Microbiology, School of Medicine and National Emerging Infectious Diseases Laboratories Institute, Boston University, Boston, MA 02118, USA.
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14
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Usami K, Matsuno K, Igarashi M, Denda-Nagai K, Takada A, Irimura T. Involvement of viral envelope GP2 in Ebola virus entry into cells expressing the macrophage galactose-type C-type lectin. Biochem Biophys Res Commun 2011; 407:74-8. [PMID: 21362405 DOI: 10.1016/j.bbrc.2011.02.110] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 02/22/2011] [Indexed: 11/24/2022]
Abstract
Ebola virus (EBOV) infection is initiated by the interaction of the viral surface envelope glycoprotein (GP) with the binding sites on target cells. Differences in the mortality among different species of the Ebola viruses, i.e., Zaire ebolavirus (ZEBOV) and Reston ebolavirus (REBOV), correspond to the in vitro infectivity of the pseudo-typed virus constructed with the GPs in cells expressing macrophage galactose-type calcium-type lectin (MGL/CD301). Through mutagenesis of GP2, the transmembrane-anchored subunit of GP, we found that residues 502-527 of the GP2 sequence determined the different infectivity between VSV-ZEBOV GP and -REBOV GP in MGL/CD301-expressing cells and a histidine residue at position 516 of ZEBOV GP2 appeared essential in the differential infectivity. These findings may provide a clue to clarify a molecular basis of different pathogenicity among EBOV species.
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Affiliation(s)
- Katsuaki Usami
- Laboratory of Cancer Biology and Molecular Immunology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
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15
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Kuhn JH, Becker S, Ebihara H, Geisbert TW, Johnson KM, Kawaoka Y, Lipkin WI, Negredo AI, Netesov SV, Nichol ST, Palacios G, Peters CJ, Tenorio A, Volchkov VE, Jahrling PB. Proposal for a revised taxonomy of the family Filoviridae: classification, names of taxa and viruses, and virus abbreviations. Arch Virol 2010; 155:2083-103. [PMID: 21046175 PMCID: PMC3074192 DOI: 10.1007/s00705-010-0814-x] [Citation(s) in RCA: 296] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 09/16/2010] [Indexed: 11/30/2022]
Abstract
The taxonomy of the family Filoviridae (marburgviruses and ebolaviruses) has changed several times since the discovery of its members, resulting in a plethora of species and virus names and abbreviations. The current taxonomy has only been partially accepted by most laboratory virologists. Confusion likely arose for several reasons: species names that consist of several words or which (should) contain diacritical marks, the current orthographic identity of species and virus names, and the similar pronunciation of several virus abbreviations in the absence of guidance for the correct use of vernacular names. To rectify this problem, we suggest (1) to retain the current species names Reston ebolavirus, Sudan ebolavirus, and Zaire ebolavirus, but to replace the name Cote d'Ivoire ebolavirus [sic] with Taï Forest ebolavirus and Lake Victoria marburgvirus with Marburg marburgvirus; (2) to revert the virus names of the type marburgviruses and ebolaviruses to those used for decades in the field (Marburg virus instead of Lake Victoria marburgvirus and Ebola virus instead of Zaire ebolavirus); (3) to introduce names for the remaining viruses reminiscent of jargon used by laboratory virologists but nevertheless different from species names (Reston virus, Sudan virus, Taï Forest virus), and (4) to introduce distinct abbreviations for the individual viruses (RESTV for Reston virus, SUDV for Sudan virus, and TAFV for Taï Forest virus), while retaining that for Marburg virus (MARV) and reintroducing that used over decades for Ebola virus (EBOV). Paying tribute to developments in the field, we propose (a) to create a new ebolavirus species (Bundibugyo ebolavirus) for one member virus (Bundibugyo virus, BDBV); (b) to assign a second virus to the species Marburg marburgvirus (Ravn virus, RAVV) for better reflection of now available high-resolution phylogeny; and (c) to create a new tentative genus (Cuevavirus) with one tentative species (Lloviu cuevavirus) for the recently discovered Lloviu virus (LLOV). Furthermore, we explain the etymological derivation of individual names, their pronunciation, and their correct use, and we elaborate on demarcation criteria for each taxon and virus.
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Affiliation(s)
- Jens H Kuhn
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, National Interagency Biodefense Campus, B-8200 Research Plaza, Fort Detrick, Frederick, MD 21702, USA.
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16
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The Tyro3 receptor kinase Axl enhances macropinocytosis of Zaire ebolavirus. J Virol 2010; 85:334-47. [PMID: 21047970 DOI: 10.1128/jvi.01278-09] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Axl, a plasma membrane-associated Tyro3/Axl/Mer (TAM) family member, is necessary for optimal Zaire ebolavirus (ZEBOV) glycoprotein (GP)-dependent entry into some permissive cells but not others. To date, the role of Axl in virion entry is unknown. The focus of this study was to characterize entry pathways that are used for ZEBOV uptake in cells that require Axl for optimal transduction and to define the role of Axl in this process. Through the use of biochemical inhibitors, interfering RNA (RNAi), and dominant negative constructs, we demonstrate that ZEBOV-GP-dependent entry into these cells occurs through multiple uptake pathways, including both clathrin-dependent and caveola/lipid raft-mediated endocytosis. Other dynamin-dependent and -independent pathways such as macropinocytosis that mediate high-molecular-weight dextran uptake also stimulated ZEBOV-GP entry into these cells, and inhibitors that are known to block macropinocytosis inhibited both dextran uptake and ZEBOV infection. These findings provided strong evidence for the importance of this pathway in filovirus entry. Reduction of Axl expression by RNAi treatment resulted in decreased ZEBOV entry via macropinocytosis but had no effect on the clathrin-dependent or caveola/lipid raft-mediated endocytic mechanisms. Our findings demonstrate for the first time that Axl enhances macropinocytosis, thereby increasing productive ZEBOV entry.
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17
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Wenigenrath J, Kolesnikova L, Hoenen T, Mittler E, Becker S. Establishment and application of an infectious virus-like particle system for Marburg virus. J Gen Virol 2010; 91:1325-34. [PMID: 20071483 DOI: 10.1099/vir.0.018226-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The highly pathogenic Marburg virus (MARV) can only be investigated in high containment laboratories, which is time consuming and expensive. To investigate the MARV life cycle under normal laboratory conditions, an infectious virus-like particle (VLP) system was developed. The infectious VLP system is based on the T7-polymerase driven synthesis of a MARV-specific minigenome that encodes luciferase and is transcribed and replicated by the simultaneously expressed MARV nucleocapsid proteins NP, VP35, L and VP30. Transcription of the minigenome resulted in luciferase activity and replication resulted in encapsidated minigenomes. The encapsidated minigenomes, together with the viral matrix proteins VP40 and VP24 and the surface glycoprotein (GP), formed VLPs at the plasma membrane. Among the released pleomorphic VLPs, filamentous particles of 200-400 nm in length showed the highest capacity to induce reporter activity upon infection of target cells. To characterize the infectious VLP system, the intracellular concentration of one of the components was titrated, while all others were held constant. Intracellular concentrations of nucleocapsid proteins that resulted in highest replication and transcription activities also yielded VLPs with the highest ability to induce luciferase activity in target cells. High intracellular levels of VP40 maximized the release of VLPs, but reduced their ability to induce luciferase activity in target cells. The intracellular concentration of GP positively correlated with its incorporation into VLPs and their infectivity. Finally, we demonstrated that the infectious VLP system was suitable for rapid screening of neutralizing antibodies directed against MARV.
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Affiliation(s)
- Jörg Wenigenrath
- Institut für Virologie, Philipps-Universität Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany
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18
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Influence of proline on the thermostability of the active site and membrane arrangement of transmembrane proteins. Biophys J 2008; 95:4384-95. [PMID: 18658225 DOI: 10.1529/biophysj.108.136747] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proline residues play a fundamental and subtle role in the dynamics, structure, and function in many membrane proteins. Temperature derivative spectroscopy and differential scanning calorimetry have been used to determine the effect of proline substitution in the structural stability of the active site and transmembrane arrangement of bacteriorhodopsin. We have analyzed the Pro-to-Ala mutation for the helix-embedded prolines Pro50, Pro91, and Pro186 in the native membrane environment. This information has been complemented with the analysis of the respective crystallographic structures by the FoldX force field. Differential scanning calorimetry allowed us to determine distorted membrane arrangement for P50A and P186A. The protein stability was severely affected for P186A and P91A. In the case of Pro91, a single point mutation is capable of strongly slowing down the conformational diffusion along the denaturation coordinate, becoming a barrier-free downhill process above 371 K. Temperature derivative spectroscopy, applied for first time to study thermal stability of proteins, has been used to monitor the stability of the active site of bacteriorhodopsin. The mutation of Pro91 and Pro186 showed the most striking effects on the retinal binding pocket. These residues are the Pro in closer contact to the active site (activation energies for retinal release of 60.1 and 76.8 kcal/mol, respectively, compared to 115.8 kcal/mol for WT). FoldX analysis of the protein crystal structures indicates that the Pro-to-Ala mutations have both local and long-range effects on the structural stability of residues involved in the architecture of the protein and the active site and in the proton pumping function. Thus, this study provides a complete overview of the substitution effect of helix-embedded prolines in the thermodynamic and dynamic stability of a membrane protein, also related to its structure and function.
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19
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Towner JS, Khristova ML, Sealy TK, Vincent MJ, Erickson BR, Bawiec DA, Hartman AL, Comer JA, Zaki SR, Ströher U, Gomes da Silva F, del Castillo F, Rollin PE, Ksiazek TG, Nichol ST. Marburgvirus genomics and association with a large hemorrhagic fever outbreak in Angola. J Virol 2006; 80:6497-516. [PMID: 16775337 PMCID: PMC1488971 DOI: 10.1128/jvi.00069-06] [Citation(s) in RCA: 222] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In March 2005, the Centers for Disease Control and Prevention (CDC) investigated a large hemorrhagic fever (HF) outbreak in Uige Province in northern Angola, West Africa. In total, 15 initial specimens were sent to CDC, Atlanta, Ga., for testing for viruses associated with viral HFs known to be present in West Africa, including ebolavirus. Marburgvirus was also included despite the fact that the origins of all earlier outbreaks were linked directly to East Africa. Surprisingly, marburgvirus was confirmed (12 of 15 specimens) as the cause of the outbreak. The outbreak likely began in October 2004 and ended in July 2005, and it included 252 cases and 227 (90%) fatalities (report from the Ministry of Health, Republic of Angola, 2005), making it the largest Marburg HF outbreak on record. A real-time quantitative reverse transcription-PCR assay utilized and adapted during the outbreak proved to be highly sensitive and sufficiently robust for field use. Partial marburgvirus RNA sequence analysis revealed up to 21% nucleotide divergence among the previously characterized East African strains, with the most distinct being Ravn from Kenya (1987). The Angolan strain was less different ( approximately 7%) from the main group of East African marburgviruses than one might expect given the large geographic separation. To more precisely analyze the virus genetic differences between outbreaks and among viruses within the Angola outbreak itself, a total of 16 complete virus genomes were determined, including those of the virus isolates Ravn (Kenya, 1987) and 05DRC, 07DRC, and 09DRC (Democratic Republic of Congo, 1998) and the reference Angolan virus isolate (Ang1379v). In addition, complete genome sequences were obtained from RNAs extracted from 10 clinical specimens reflecting various stages of the disease and locations within the Angolan outbreak. While the marburgviruses exhibit high overall genetic diversity (up to 22%), only 6.8% nucleotide difference was found between the West African Angolan viruses and the majority of East African viruses, suggesting that the virus reservoir species in these regions are not substantially distinct. Remarkably few nucleotide differences were found among the Angolan clinical specimens (0 to 0.07%), consistent with an outbreak scenario in which a single (or rare) introduction of virus from the reservoir species into the human population was followed by person-to-person transmission with little accumulation of mutations. This is in contrast to the 1998 to 2000 marburgvirus outbreak, where evidence of several virus genetic lineages (with up to 21% divergence) and multiple virus introductions into the human population was found.
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Affiliation(s)
- Jonathan S Towner
- Special Pathogens Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Mailstop G14, Atlanta, GA 30333, USA
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20
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Marzi A, Wegele A, Pöhlmann S. Modulation of virion incorporation of Ebolavirus glycoprotein: effects on attachment, cellular entry and neutralization. Virology 2006; 352:345-56. [PMID: 16777170 DOI: 10.1016/j.virol.2006.04.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 02/23/2006] [Accepted: 04/27/2006] [Indexed: 01/09/2023]
Abstract
The filoviruses Ebolavirus (EBOV) and Marburgvirus (MARV) cause severe hemorrhagic fever in humans and are potential agents of biological warfare. The envelope glycoprotein (GP) of filoviruses mediates viral entry into cells and is an attractive target for therapeutic intervention and vaccine design. Here, we asked if the efficiency of virion incorporation of EBOV-GP impacts attachment and entry into target cells and modulates susceptibility to neutralizing antibodies. In order to control the level of EBOV-GP expression, we generated cell lines expressing the GPs of the four known EBOV subspecies in an inducible fashion. Regulated expression of GP on the cell surface allowed production of reporter viruses harboring different amounts of GP. A pronounced reduction of virion incorporation of EBOV-GP had relatively little effect on virion infectivity, suggesting that only a few copies of GP might be sufficient for efficient engagement of cellular receptors. In contrast, optimal interactions with cellular attachment factors like the DC-SIGN protein required incorporation of high amounts of GP. Antibody-mediated neutralization of virions bearing high amounts of GP was slightly more efficient than neutralization of virions harboring low amounts of GP, suggesting that the efficiency of GP incorporation into virions might modulate susceptibility to neutralizing antibodies. Finally, regulated expression of GP in permissive 293 cells did not reduce EBOV-GP-driven infection but diminished vesicular stomatitis virus GP (VSV-G) and amphotropic murine leukemia virus (A-MLV) GP mediated entry in a dose-dependent manner. Therefore, intracellular GP does not seem to downmodulate expression of its receptor(s) but might alter expression and/or function of molecules involved in VSV-G and A-MLV-GP-dependent entry. Our results suggest that the efficiency of virion incorporation of GP could impact EBOV attachment to target cells and might modulate control of viral spread by the humoral immune response.
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Affiliation(s)
- Andrea Marzi
- Institute for Clinical and Molecular Virology, University Erlangen-Nürnberg, 91054 Erlangen, Germany
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21
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Alazard-Dany N, Volchkova V, Reynard O, Carbonnelle C, Dolnik O, Ottmann M, Khromykh A, Volchkov VE. Ebola virus glycoprotein GP is not cytotoxic when expressed constitutively at a moderate level. J Gen Virol 2006; 87:1247-1257. [PMID: 16603527 DOI: 10.1099/vir.0.81361-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Transient expression of Ebola virus (EBOV) glycoprotein GP causes downregulation of surface proteins, cell rounding and detachment, a phenomenon believed to play a central role in the pathogenicity of the virus. In this study, evidence that moderate expression of GP does not result in such morphological changes was provided. It was shown that GP continuously produced in 293T cells from the Kunjin virus replicon was correctly processed and transported to the plasma membrane without affecting the surface expression of β1 and α5 integrins and major histocompatibility complex I molecules. The level of GP expression in Kunjin replicon GP-expressing cells was similar to that observed in cells infected with EBOV early in infection and lower than that produced in cells transfected with plasmid DNA, phCMV-GP, expressing GP from a strong promoter. Importantly, transient transfection of Kunjin replicon GP-expressing cells with GP-coding plasmid DNA resulted in overexpression of GP, which lead to the downregulation of surface molecules and massive rounding and detachment of transfected cells. Here, it was also demonstrated that cell rounding and downregulation of the surface markers are the late events in EBOV infection, whereas synthesis and massive release of virus particles occur at early steps and do not cause significant cytotoxic effects. These findings indicate that the synthesis of EBOV GP in virus-infected cells is controlled well by several mechanisms that do not allow GP overexpression and hence the early appearance of its cytotoxic properties.
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Affiliation(s)
- Nathalie Alazard-Dany
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Valentina Volchkova
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Olivier Reynard
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Caroline Carbonnelle
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Olga Dolnik
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Michèle Ottmann
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Alexander Khromykh
- School of Molecular and Microbial Sciences, University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Viktor E Volchkov
- Filovirus Laboratory, Claude Bernard University Lyon 1, INSERM U758, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
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22
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Sinn PL, Burnight ER, Shen H, Fan H, McCray PB. Inclusion of Jaagsiekte sheep retrovirus proviral elements markedly increases lentivirus vector pseudotyping efficiency. Mol Ther 2005; 11:460-9. [PMID: 15727943 DOI: 10.1016/j.ymthe.2004.10.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Revised: 10/11/2004] [Accepted: 10/26/2004] [Indexed: 11/23/2022] Open
Abstract
Retroviral pseudotyping for gene transfer applications endeavors to alter vector tropism and maintain a suitable titer. We investigated the compatibility of the Jaagsiekte sheep retrovirus (JSRV) envelope glycoprotein with the feline immunodeficiency virus (FIV) vector. A construct consisting of the minimal JSRV env coding region expressed from a standard mammalian expression plasmid generated FIV vector titers of approximately 10(4) TU/ml following standard triple transfection, collection of supernatants, and concentration by centrifuge. Interestingly, retention of the native proviral 5' and 3' flanking regions surrounding the JSRV env resulted in exceptional titers of approximately 10(8) TU/ml following the same viral preparation. To discern the regions necessary to achieve this 10,000-fold increase in titer, additional constructs were designed and tested. Our results indicate that the enhanced vector titer correlates with an increase in steady-state levels of envelope RNA that results from a combination of RNA splicing and stability, leading to increased envelope protein production. Expression of four other glycoproteins in an expression plasmid retaining the enhancing elements from the JSRV proviral sequence increased FIV vector titers from 0- to 100-fold. These novel data demonstrate that optimization of the envelope expression construct can profoundly influence titers for lentivirus vectors.
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Affiliation(s)
- Patrick L Sinn
- Department of Pediatrics, Program in Gene Therapy, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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23
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Fowler T, Bamberg S, Möller P, Klenk HD, Meyer TF, Becker S, Rudel T. Inhibition of Marburg virus protein expression and viral release by RNA interference. J Gen Virol 2005; 86:1181-1188. [PMID: 15784912 DOI: 10.1099/vir.0.80622-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High mortality rates and lack of an available vaccine against Marburg haemorrhagic fever (MHF) highlight the need for a defensive therapy against MHF and greater knowledge of the causative agent, the Marburg virus (MARV). Here, RNA interference (RNAi) is employed to destroy MARV transcripts, disrupting replication and allowing analysis of various roles of MARV proteins. Small interfering RNAs (siRNAs) homologous to three MARV transcripts (NP, VP35 and VP30) were co-transfected into cells with plasmids encoding the corresponding nucleocapsid proteins. The resulting decrease in MARV nucleocapsid-protein levels was shown to be specific, as siRNA that was not homologous to the MARV genome did not decrease the levels of viral nucleocapsid proteins. Additionally, transcript levels of double-stranded RNA (dsRNA)-sensor proteins, the dsRNA-activated protein kinase and 2',5'-oligoadenylate synthetase 1 remained unchanged, suggesting that the decrease in viral proteins was not a result of activation of the antiviral properties of the interferon system. Subsequently, siRNAs were shown to reduce intracellular viral proteins in MARV-infected cells and viral material released into the medium. Targeted reduction of VP30 downregulated the intracellular levels of all other viral proteins, suggesting that VP30 plays an essential role for transcription/replication. The efficient reduction of MARV replication also suggests that RNAi may provide an agent against MHF.
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Affiliation(s)
- Trent Fowler
- Max Planck Institute for Infection Biology, Schumannstrasse 21/22, Campus Charité Mitte, 10117 Berlin, Germany
| | - Sandra Bamberg
- Institute of Virology, Philipps University Marburg, Robert-Koch-Strasse 17, 35037 Marburg, Germany
| | - Peggy Möller
- Institute of Virology, Philipps University Marburg, Robert-Koch-Strasse 17, 35037 Marburg, Germany
| | - Hans-Dieter Klenk
- Institute of Virology, Philipps University Marburg, Robert-Koch-Strasse 17, 35037 Marburg, Germany
| | - Thomas F Meyer
- Max Planck Institute for Infection Biology, Schumannstrasse 21/22, Campus Charité Mitte, 10117 Berlin, Germany
| | - Stephan Becker
- Institute of Virology, Philipps University Marburg, Robert-Koch-Strasse 17, 35037 Marburg, Germany
| | - Thomas Rudel
- Max Planck Institute for Infection Biology, Schumannstrasse 21/22, Campus Charité Mitte, 10117 Berlin, Germany
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24
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Volchkov VE, Volchkova VA, Dolnik O, Feldmann H, Klenk HD. Polymorphism of Filovirus Glycoproteins. Adv Virus Res 2005; 64:359-81. [PMID: 16139600 DOI: 10.1016/s0065-3527(05)64011-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Viktor E Volchkov
- Biologie des Filovirus, Claude Bernard University Lyon, INSERM U412 69365 Lyon, France
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25
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Sinn PL, Hickey MA, Staber PD, Dylla DE, Jeffers SA, Davidson BL, Sanders DA, McCray PB. Lentivirus vectors pseudotyped with filoviral envelope glycoproteins transduce airway epithelia from the apical surface independently of folate receptor alpha. J Virol 2003; 77:5902-10. [PMID: 12719583 PMCID: PMC154009 DOI: 10.1128/jvi.77.10.5902-5910.2003] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The practical application of gene therapy as a treatment for cystic fibrosis is limited by poor gene transfer efficiency with vectors applied to the apical surface of airway epithelia. Recently, folate receptor alpha (FR alpha), a glycosylphosphatidylinositol-linked surface protein, was reported to be a cellular receptor for the filoviruses. We found that polarized human airway epithelia expressed abundant FR alpha on their apical surface. In an attempt to target these apical receptors, we pseudotyped feline immunodeficiency virus (FIV)-based vectors by using envelope glycoproteins (GPs) from the filoviruses Marburg virus and Ebola virus. Importantly, primary cultures of well-differentiated human airway epithelia were transduced when filovirus GP-pseudotyped FIV was applied to the apical surface. Furthermore, by deleting a heavily O-glycosylated extracellular domain of the Ebola GP, we improved the titer of concentrated vector severalfold. To investigate the folate receptor dependence of gene transfer with the filovirus pseudotypes, we compared gene transfer efficiency in immortalized airway epithelium cell lines and primary cultures. By utilizing phosphatidylinositol-specific phospholipase C (PI-PLC) treatment and FR alpha-blocking antibodies, we demonstrated FR alpha-dependent and -independent entry by filovirus glycoprotein-pseudotyped FIV-based vectors in airway epithelia. Of particular interest, entry independent of FR alpha was observed in primary cultures of human airway epithelia. Understanding viral vector binding and entry pathways is fundamental for developing cystic fibrosis gene therapy applications.
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Affiliation(s)
- Patrick L Sinn
- Program in Gene Therapy, Department of Pediatrics, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
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26
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Sui J, Marasco WA. Evidence against Ebola virus sGP binding to human neutrophils by a specific receptor. Virology 2002; 303:9-14. [PMID: 12482654 DOI: 10.1006/viro.2002.1715] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The issue of whether Ebola secretory glycoprotein (sGP) binds to human neutrophils via the IgG Fc receptor IIIb (FcgammaRIIIb, CD16b) or other receptors has been controversial. To clarify this, FACS analysis, an sGP absorption assay, and direct binding of (125)I-sGP to neutrophils were performed. Results from FACS analysis demonstrated that limited washing conditions leads to the nonspecific formation of immune complexes on the neutrophil surface and this, but not a specific interaction between sGP and CD16b, is responsible for the previous observations. An sGP absorption assay also demonstrated that sGP is not specifically bound but is nonspecifically proteolysed by proteases released from neutrophils. Finally, there was no difference in (125)I-sGP binding to neutrophils compared to other control cell types. Taken together, these results demonstrate that neutrophils do not express a specific receptor for Ebola virus sGP. It is unlikely that sGP plays a role in the Ebola virus pathogenesis through interfering with the innate immunity by targeting neutrophils.
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Affiliation(s)
- Jianhua Sui
- Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, Massachusetts, 02115, USA
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27
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Groseth A, Ströher U, Theriault S, Feldmann H. Molecular characterization of an isolate from the 1989/90 epizootic of Ebola virus Reston among macaques imported into the United States. Virus Res 2002; 87:155-63. [PMID: 12191779 DOI: 10.1016/s0168-1702(02)00087-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have determined the entire genomic sequence of the Pennsylvania strain, which was isolated along with the Virginia strain during the emergence of Ebola virus Reston in 1989/90 in the United States. Thus, either the Pennsylvania or Virginia strain, neither of which had been previously molecularly characterized, can be considered as the prototype for Ebola virus Reston. Comparative analysis showed a high degree of homology to the concomitantly analyzed and recently published Philippine strain of EBOV Reston from 1996 (Ikegami et al., Arch. Virol., 146 (2001) 2021). In comparison to EBOV Zaire, strain Mayinga, conservation could be found within the open reading frames, the 3' leader and 5' trailer region and the transcriptional signals, whereas the non-coding and intergenic regions did not show any homology. This clearly supports that EBOV Reston is a distinct species within the genus Ebola-like virus but which seems to be similar to other members with respect to transcription and replication strategies. The sequence determination provides the basis for the development of a reverse genetics system for Ebola virus Reston, which is needed to study differences in pathogenicity among filoviruses.
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Affiliation(s)
- Allison Groseth
- Special Pathogens Program, Canadian Science Centre for Human and Animal Health, 1015 Arlington Street, Winnipeg, Manitoba, Canada R3E 3R2
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28
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Sänger C, Mühlberger E, Lötfering B, Klenk HD, Becker S. The Marburg virus surface protein GP is phosphorylated at its ectodomain. Virology 2002; 295:20-9. [PMID: 12033762 DOI: 10.1006/viro.2002.1374] [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: 01/16/2023]
Abstract
Marburg virus, a filovirus, contains only one transmembrane protein (GP) which is responsible for receptor recognition on target cells. GP, a type I membrane protein of approximately 220 kDa, is acylated and highly glycosylated carrying N- and O-linked sugar side chains. GP is transported through the exocytotic pathway toward the plasma membrane where budding of virions takes place. In the trans-Golgi network, GP is proteolytically activated by the prohormone convertase furin into two subunits GP(1) and GP(2). In the present paper, we provide evidence that GP undergoes an additional posttranslational modification; it is phosphorylated at its ectodomain. Phosphorylation takes place at serine residues between amino acid 260 and 273. The respective serines are located in conserved recognition sites for luminal protein kinases (protein kinase CK II and Golgi casein kinase). Consistent with this data, it was found that GP was phosphorylated in the Golgi apparatus of the expressing HeLa cells before cleavage of the molecule. GP is the first example of a viral glycoprotein with a phosphorylated ectodomain.
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Affiliation(s)
- Christian Sänger
- Institut für Virologie der Philipps-Universität Marburg, Robert-Koch-Str. 17, Marburg, 35037, Germany
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29
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Feldmann H, Volchkov VE, Volchkova VA, Ströher U, Klenk HD. Biosynthesis and role of filoviral glycoproteins. J Gen Virol 2001; 82:2839-2848. [PMID: 11714958 DOI: 10.1099/0022-1317-82-12-2839] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Heinz Feldmann
- Canadian Science Centre for Human and Animal Health, 1015 Arlington Street, Winnipeg, Manitoba, CanadaR3E 3R21
| | - Viktor E Volchkov
- Biologie des Filovirus, Claude Bernard University Lyon-1, 46 Allée d'Italie, 69007 Lyon, France2
| | - Valentina A Volchkova
- Biologie des Filovirus, Claude Bernard University Lyon-1, 46 Allée d'Italie, 69007 Lyon, France2
| | - Ute Ströher
- Institut für Virologie, Philipps-Universität, Robert-Koch-Str. 17, D-35037 Marburg, Germany3
| | - Hans-Dieter Klenk
- Institut für Virologie, Philipps-Universität, Robert-Koch-Str. 17, D-35037 Marburg, Germany3
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30
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Bénit L, Dessen P, Heidmann T. Identification, phylogeny, and evolution of retroviral elements based on their envelope genes. J Virol 2001; 75:11709-19. [PMID: 11689652 PMCID: PMC114757 DOI: 10.1128/jvi.75.23.11709-11719.2001] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phylogenetic analyses of retroviral elements, including endogenous retroviruses, have relied essentially on the retroviral pol gene expressing the highly conserved reverse transcriptase. This enzyme is essential for the life cycle of all retroid elements, but other genes are also endowed with conserved essential functions. Among them, the transmembrane (TM) subunit of the envelope gene is involved in virus entry through membrane fusion. It has also been reported to contain a domain, named the immunosuppressive domain, that has immunosuppressive properties most probably essential for virus spread within the host. This domain is conserved among a large series of retroviral elements, and we have therefore attempted to generate phylogenetic links between retroviral elements identified from databases following tentative alignments of the immunosuppressive domain and adjacent sequences. This allowed us to unravel a conserved organization among TM domains, also found in the Ebola and Marburg filoviruses, and to identify a large number of human endogenous retroviruses (HERVs) from sequence databases. The latter elements are part of previously identified families of HERVs, and some of them define new families. A general phylogenetic analysis based on the TM proteins of retroelements, and including those with no clearly identified immunosuppressive domain, could then be derived and compared with pol-based phylogenetic trees, providing a comprehensive survey of retroelements and definitive evidence for recombination events in the generation of both the endogenous and the present-day infectious retroviruses.
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Affiliation(s)
- L Bénit
- Unité des Rétrovirus Endogènes et Eléments Rétroïdes des Eucaryotes Supérieurs, CNRS UMR 1573, Institut Gustave Roussy, 94805 Villejuif Cedex, France
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31
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Hevey M, Negley D, VanderZanden L, Tammariello RF, Geisbert J, Schmaljohn C, Smith JF, Jahrling PB, Schmaljohn AL. Marburg virus vaccines: comparing classical and new approaches. Vaccine 2001; 20:586-93. [PMID: 11672925 DOI: 10.1016/s0264-410x(01)00353-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An effort to develop a safe and effective vaccine for Marburg virus (MBGV), one of the filoviruses known to cause high mortality rates in humans, led us to compare directly some of the merits of modern versus classical vaccine approaches for this agent. Prior work had established the MBGV-glycoprotein (GP), the only known virion surface antigen, as a candidate for inclusion in a vaccine. In this study, we vaccinated groups of Hartley guinea pigs with killed MBGV, live attenuated MBGV, soluble MBGV-GP expressed by baculovirus recombinants, MBGV-GP delivered as a DNA vaccine, or MBGV-GP delivered via an alphavirus RNA replicon. Serological responses were evaluated, and animals were challenged with a lethal dose of MBGV given either subcutaneously or via aerosol. Killed MBGV and replicon-delivered MBGV-GP were notably immunogenic and protective against MBGV, but results did not exclude any approach and suggested a role for DNA vaccines in immunological priming.
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Affiliation(s)
- M Hevey
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA
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32
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Volchkov VE, Volchkova VA, Muhlberger E, Kolesnikova LV, Weik M, Dolnik O, Klenk HD. Recovery of infectious Ebola virus from complementary DNA: RNA editing of the GP gene and viral cytotoxicity. Science 2001; 291:1965-9. [PMID: 11239157 DOI: 10.1126/science.1057269] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To study the mechanisms underlying the high pathogenicity of Ebola virus, we have established a system that allows the recovery of infectious virus from cloned cDNA and thus permits genetic manipulation. We created a mutant in which the editing site of the gene encoding envelope glycoprotein (GP) was eliminated. This mutant no longer expressed the nonstructural glycoprotein sGP. Synthesis of GP increased, but most of it accumulated in the endoplasmic reticulum as immature precursor. The mutant was significantly more cytotoxic than wild-type virus, indicating that cytotoxicity caused by GP is down-regulated by the virus through transcriptional RNA editing and expression of sGP.
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Affiliation(s)
- V E Volchkov
- Institut für Virologie, Philipps-Universität, Robert-Koch-Strasse 17, 35037 Marburg, Germany.
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33
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Sänger C, Mühlberger E, Ryabchikova E, Kolesnikova L, Klenk HD, Becker S. Sorting of Marburg virus surface protein and virus release take place at opposite surfaces of infected polarized epithelial cells. J Virol 2001; 75:1274-83. [PMID: 11152500 PMCID: PMC114033 DOI: 10.1128/jvi.75.3.1274-1283.2001] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Marburg virus, a filovirus, causes severe hemorrhagic fever with hitherto poorly understood molecular pathogenesis. We have investigated here the vectorial transport of the surface protein GP of Marburg virus in polarized epithelial cells. To this end, we established an MDCKII cell line that was able to express GP permanently (MDCK-GP). The functional integrity of GP expressed in these cells was analyzed using vesicular stomatitis virus pseudotypes. Further experiments revealed that GP is transported in MDCK-GP cells mainly to the apical membrane and is released exclusively into the culture medium facing the apical membrane. When MDCKII cells were infected with Marburg virus, the majority of GP was also transported to the apical membrane, suggesting that the protein contains an autonomous apical transport signal. Release of infectious progeny virions, however, took place exclusively at the basolateral membrane of the cells. Thus, vectorial budding of Marburg virus is presumably determined by factors other than the surface protein.
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Affiliation(s)
- C Sänger
- Institut für Virologie, Philipps-Universität Marburg, D-35037 Marburg, Germany
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34
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Sänger C, Mühlberger E, Klenk HD, Becker S. Adverse effects of MVA-T7 on the transport of Marburg virus glycoprotein. J Virol Methods 2001; 91:29-35. [PMID: 11164483 DOI: 10.1016/s0166-0934(00)00239-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Expression of glycoproteins has been carried out successfully using recombinant vaccinia virus vectors. Especially attractive is the use of recombinant vaccinia viruses which express the DNA-dependent RNA polymerase of the phage T7 (T7-polymerase). The T7-polynerase drives the transcription of plasmid-based genes under the control of the T7 RNA polymerase promoter transfected into the infected cell. Comparison of two different recombinant vaccinia viruses, vTF7-3 and MVA-T7, revealed that post-translational processing of Marburg virus surface glycoprotein (GP) is impaired in the MVA-T7 but not in the vTF7-3 system. Influenza virus hemagglutinin, however, was transported and processed like the authentic protein in both systems. It is shown that transport of GP in the MVA-T7 system is not completely blocked, but the vast majority of molecules remained Endo H-sensitive. Only trace amounts evaded the endoplasmatic reticulum and reached the plasma membrane. Thus, the adverse effects of MVA-T7 on the processing of recombinant glycoproteins cannot be predicted, and correct processing has to be investigated for every expressed glycoprotein.
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Affiliation(s)
- C Sänger
- Institut für Virologie der Philipps, Universität Marburg, Robert-Koch-Strasse 17, D-35037, Marburg, Germany
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35
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Chan SY, Ma MC, Goldsmith MA. Differential induction of cellular detachment by envelope glycoproteins of Marburg and Ebola (Zaire) viruses. J Gen Virol 2000; 81:2155-2159. [PMID: 10950971 DOI: 10.1099/0022-1317-81-9-2155] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human infection by Marburg (MBG) or Ebola (EBO) virus is associated with fatal haemorrhagic fevers. While these filoviruses may both incite disease as a result of explosive virus replication, we hypothesized that expression of individual viral gene products, such as the envelope glycoprotein (GP), may directly alter target cells and contribute to pathogenesis. We found that expression of EBO GP in 293T cells caused significant levels of cellular detachment in the absence of cell death or virus replication. This detachment was induced most potently by membrane-bound EBO GP, rather than the shed glycoprotein products (sGP or GP1), and was largely attributable to a domain within the extracellular region of GP2. Furthermore, detachment was blocked by the Ser/Thr kinase inhibitor 2-aminopurine, suggesting the importance of a phosphorylation-dependent signalling cascade in inducing detachment. Since MBG GP did not induce similar cellular detachment, MBG and EBO GP interact with target cells by distinct processes to elicit cellular dysregulation.
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Affiliation(s)
- Stephen Y Chan
- Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA 94141-9100, USA2
- Gladstone Institute of Virology and Immunology, PO Box 419100, San Francisco, CA 94141-9100, USA1
| | - Melissa C Ma
- Gladstone Institute of Virology and Immunology, PO Box 419100, San Francisco, CA 94141-9100, USA1
| | - Mark A Goldsmith
- Department of Medicine, School of Medicine, University of California San Francisco, San Francisco, CA 94141-9100, USA2
- Gladstone Institute of Virology and Immunology, PO Box 419100, San Francisco, CA 94141-9100, USA1
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36
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Chan SY, Speck RF, Ma MC, Goldsmith MA. Distinct mechanisms of entry by envelope glycoproteins of Marburg and Ebola (Zaire) viruses. J Virol 2000; 74:4933-7. [PMID: 10775638 PMCID: PMC112022 DOI: 10.1128/jvi.74.10.4933-4937.2000] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since the Marburg (MBG) and Ebola (EBO) viruses have sequence homology and cause similar diseases, we hypothesized that they associate with target cells by similar mechanisms. Pseudotype viruses prepared with a luciferase-containing human immunodeficiency virus type 1 backbone and packaged by the MBG virus or the Zaire subtype EBO virus glycoproteins (GP) mediated infection of a comparable wide range of mammalian cell types, and both were inhibited by ammonium chloride. In contrast, they exhibited differential sensitivities to treatment of target cells with tunicamycin, endoglycosidase H, or protease (pronase). Therefore, while they exhibit certain functional similarities, the MBG and EBO virus GP interact with target cells by distinct processes.
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Affiliation(s)
- S Y Chan
- Gladstone Institute of Virology and Immunology, San Francisco, California 94141-9100, USA
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37
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Volchkov VE, Volchkova VA, Ströher U, Becker S, Dolnik O, Cieplik M, Garten W, Klenk HD, Feldmann H. Proteolytic processing of Marburg virus glycoprotein. Virology 2000; 268:1-6. [PMID: 10683320 DOI: 10.1006/viro.1999.0110] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Processing of the transmembrane glycoprotein (GP) of Marburg virus involved the conversion of an endo H-sensitive, ER-specific form into an endo H-resistant, Golgi-specific precursor that was cleaved into GP(1) and GP(2). Cleavage was mediated by furin or another subtilisin-like endoprotease with similar substrate specificity as indicated by mutational analysis of the cleavage site and inhibition using peptidyl chloromethylketones. Mature GP consisted of disulfide-linked GP(1) and GP(2) subunits.
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Affiliation(s)
- V E Volchkov
- Institut für Virologie, Philipps-Universität, Robert-Koch-Str. 17, Marburg, D-35037, Germany.
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38
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Feldmann H, Volchkov VE, Volchkova VA, Klenk HD. The glycoproteins of Marburg and Ebola virus and their potential roles in pathogenesis. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 1999; 15:159-69. [PMID: 10470276 DOI: 10.1007/978-3-7091-6425-9_11] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Filoviruses cause systemic infections that can lead to severe hemorrhagic fever in human and non-human primates. The primary target of the virus appears to be the mononuclear phagocytic system. As the virus spreads through the organism, the spectrum of target cells increases to include endothelial cells, fibroblasts, hepatocytes, and many other cells. There is evidence that the filovirus glycoprotein plays an important role in cell tropism, spread of infection, and pathogenicity. Biosynthesis of the glycoprotein forming the spikes on the virion surface involves cleavage by the host cell protease furin into two disulfide linked subunits GP1 and GP2. GP1 is also shed in soluble form from infected cells. Different strains of Ebola virus show variations in the cleavability of the glycoprotein, that may account for differences in pathogenicity, as has been observed with influenza viruses and paramyxoviruses. Expression of the spike glycoprotein of Ebola virus, but not of Marburg virus, requires transcriptional editing. Unedited GP mRNA yields the nonstructural glycoprotein sGP, which is secreted extensively from infected cells. Whether the soluble glycoproteins GP1 and sGP interfere with the humoral immune response and other defense mechanisms remains to be determined.
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Affiliation(s)
- H Feldmann
- Institut für Virologie, Philipps-Universität Marburg, Germany
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39
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Lötfering B, Mühlberger E, Tamura T, Klenk HD, Becker S. The nucleoprotein of Marburg virus is target for multiple cellular kinases. Virology 1999; 255:50-62. [PMID: 10049821 DOI: 10.1006/viro.1998.9577] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleoprotein (NP) of Marburg virus is phosphorylated at serine and threonine residues in a ratio of 85:15, regardless of whether the protein is isolated from virions or from eukaryotic expression systems. Phosphotyrosine is absent. Although many potential phosphorylation sites are located in the N-terminal half of NP, this part of the protein is not phosphorylated. Analyses of phosphorylation state and phosphoamino acid content of truncated NPs expressed in HeLa cells using the vaccinia virus T7 expression system led to the identification of seven phosphorylated regions (region I*, amino acids 404-432; II*, amino acids 446-472; III*, amino acids 484-511; IV*, amino acids 534-543; V*, amino acid 549; VI*, amino acids 599-604; and VII*, amino acid 619) with a minimum of seven phosphorylated amino acid residues located in the C-terminal half of NP. All phosphothreonine residues and consensus recognition sequences for protein kinase CKII are located in regions I*-V*. Regions VI* and VII* contain only phosphoserine with three of four serine residues in consensus recognition motifs for proline-directed protein kinases. Mutagenesis of proline-adjacent serine residues to alanine or aspartic acid did not influence the function of NP in a reconstituted transcription/replication system; thus it is concluded that serine phosphorylation in the most C-terminal part of NP is not a regulatory factor in viral RNA synthesis.
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Affiliation(s)
- B Lötfering
- Institut für Virologie der Philipps-Universität Marburg, Robert-Koch-Strabetae 17, Marburg, D-35037, Germany
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40
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Mühlberger E, Weik M, Volchkov VE, Klenk HD, Becker S. Comparison of the transcription and replication strategies of marburg virus and Ebola virus by using artificial replication systems. J Virol 1999; 73:2333-42. [PMID: 9971816 PMCID: PMC104478 DOI: 10.1128/jvi.73.3.2333-2342.1999] [Citation(s) in RCA: 368] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/1998] [Accepted: 11/16/1998] [Indexed: 11/20/2022] Open
Abstract
The members of the family Filoviridae, Marburg virus (MBGV) and Ebola virus (EBOV), are very similar in terms of morphology, genome organization, and protein composition. To compare the replication and transcription strategies of both viruses, an artificial replication system based on the vaccinia virus T7 expression system was established for EBOV. Specific transcription and replication of an artificial monocistronic minireplicon was demonstrated by reporter gene expression and detection of the transcribed and replicated RNA species. As it was shown previously for MBGV, three of the four EBOV nucleocapsid proteins, NP, VP35, and L, were essential and sufficient for replication. In contrast to MBGV, EBOV-specific transcription was dependent on the presence of the fourth nucleocapsid protein, VP30. When EBOV VP30 was replaced by MBGV VP30, EBOV-specific transcription was observed but with lower efficiency. Exchange of NP, VP35, and L between the two replication systems did not lead to detectable reporter gene expression. It was further observed that neither MBGV nor EBOV were able to replicate the heterologous minigenomes. A chimeric minigenome, however, containing the EBOV leader and the MBGV trailer was encapsidated, replicated, transcribed, and packaged by both viruses.
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Affiliation(s)
- E Mühlberger
- Institut für Virologie der Philipps-Universität Marburg, 35037 Marburg, Germany
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41
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Affiliation(s)
- V E Volchkov
- Institut für Virologie, Philipps-Universität Marburg, Germany
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42
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Schnittler HJ, Feldmann H. Molecular pathogenesis of filovirus infections: role of macrophages and endothelial cells. Curr Top Microbiol Immunol 1999; 235:175-204. [PMID: 9893384 DOI: 10.1007/978-3-642-59949-1_10] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- H J Schnittler
- Institut für Physiologie, Westfälische Friedrich-Wilhelms-Universität, Münster, Germany
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43
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Affiliation(s)
- H Feldmann
- Institut für Virologie, Philipps-Universität, Marburg, Germany
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44
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Becker S, Mühlberger E. Co- and posttranslational modifications and functions of Marburg virus proteins. Curr Top Microbiol Immunol 1999; 235:23-34. [PMID: 9893376 DOI: 10.1007/978-3-642-59949-1_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- S Becker
- Institut für Virologie, Philipps-Universität, Marburg, Germany
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45
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Mühlberger E, Lötfering B, Klenk HD, Becker S. Three of the four nucleocapsid proteins of Marburg virus, NP, VP35, and L, are sufficient to mediate replication and transcription of Marburg virus-specific monocistronic minigenomes. J Virol 1998; 72:8756-64. [PMID: 9765419 PMCID: PMC110291 DOI: 10.1128/jvi.72.11.8756-8764.1998] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This paper describes the first reconstituted replication system established for a member of the Filoviridae, Marburg virus (MBGV). MBGV minigenomes containing the leader and trailer regions of the MBGV genome and the chloramphenicol acetyltransferase (CAT) gene were constructed. In MBGV-infected cells, these minigenomes were replicated and encapsidated and could be passaged. Unlike most other members of the order Mononegavirales, filoviruses possess four proteins presumed to be components of the nucleocapsid (NP, VP35, VP30, and L). To determine the protein requirements for replication and transcription, a reverse genetic system was established for MBGV based on the vaccinia virus T7 expression system. Northern blot analysis of viral RNA revealed that three nucleocapsid proteins (NP, VP35, and L) were essential and sufficient for transcription as well as replication and encapsidation. These data indicate that VP35, rather than VP30, is the functional homologue of rhabdo- and paramyxovirus P proteins. The reconstituted replication system was profoundly affected by the NP-to-VP35 expression ratio. To investigate whether CAT gene expression was achieved entirely by mRNA or in part by full-length plus-strand minigenomes, a copy-back minireplicon containing the CAT gene but lacking MBGV-specific transcriptional start sites was employed in the artificial replication system. This construct was replicated without accompanying CAT activity. It was concluded that the CAT activity reflected MBGV-specific transcription and not replication.
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Affiliation(s)
- E Mühlberger
- Institut für Virologie, Philipps-Universität Marburg, 35037 Marburg, Germany
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46
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Becker S, Rinne C, Hofsäss U, Klenk HD, Mühlberger E. Interactions of Marburg virus nucleocapsid proteins. Virology 1998; 249:406-17. [PMID: 9791031 DOI: 10.1006/viro.1998.9328] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, the components of Marburg virus nucleocapsid complex were determined, and interactions between the compounds were investigated. Using salt dissociation of isolated virions, four proteins (NP, VP35, VP30, and L) remained attached to the core complex. Same proteins were detected intracellularly to be localized in MBGV-induced inclusion bodies, which are presumed to represent areas of nucleocapsid formation. To investigate interactions between the four proteins, immunofluorescence analysis of coexpressed proteins was carried out. Complexes between NP-VP35 and NP-VP30 were formed, which was demonstrated by redistribution of VP35 and VP30 into NP-induced inclusion bodies. Furthermore, complexes between L and VP35 were detected by coimmunoprecipitation. Using deletion mutants of L, the binding site of VP35 on L could be restricted to the N-terminal 530 amino-acid residues. Coexpression of NP, VP35, and L led to the formation of a triple complex where VP35 linked NP and L. The detected complexes are presumed to represent the key components of the MBGV transcription and replication machinery.
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Affiliation(s)
- S Becker
- Institut für Virologie der Philipps-Universität-Marburg, Robert-Koch-Str. 17, Marburg, 35037, Germany.
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47
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Sanchez A, Yang ZY, Xu L, Nabel GJ, Crews T, Peters CJ. Biochemical analysis of the secreted and virion glycoproteins of Ebola virus. J Virol 1998; 72:6442-7. [PMID: 9658086 PMCID: PMC109803 DOI: 10.1128/jvi.72.8.6442-6447.1998] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/1998] [Accepted: 04/17/1998] [Indexed: 02/08/2023] Open
Abstract
The glycoproteins expressed by a Zaire species of Ebola virus were analyzed for cleavage, oligomerization, and other structural properties to better define their functions. The 50- to 70-kDa secreted and 150-kDa virion/structural glycoproteins (SGP and GP, respectively), which share the 295 N-terminal residues, are cleaved near the N terminus by signalase. A second cleavage event, occurring in GP at a multibasic site (RRTRR downward arrow) that is likely mediated by furin, results in two glycoproteins (GP1 and GP2) linked by disulfide bonding. This furin cleavage site is present in the same position in the GPs of all Ebola viruses (R[R/K]X[R/K]R downward arrow), and one is predicted for Marburg viruses (R[R/K]KR downward arrow), although in a different location. Based on the results of cross-linking studies, we were able to determine that Ebola virion peplomers are composed of trimers of GP1-GP2 heterodimers and that aspects of their structure are similar to those of retroviruses, paramyxoviruses, and influenza viruses. We also determined that SGP is secreted from infected cells almost exclusively in the form of a homodimer that is joined by disulfide bonding.
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Affiliation(s)
- A Sanchez
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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48
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Volchkov VE, Volchkova VA, Slenczka W, Klenk HD, Feldmann H. Release of viral glycoproteins during Ebola virus infection. Virology 1998; 245:110-9. [PMID: 9614872 DOI: 10.1006/viro.1998.9143] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maturation and release of the Ebola virus glycoprotein GP were studied in cells infected with either Ebola or recombinant vaccinia viruses. Significant amounts of GP were found in the culture medium in nonvirion forms. The major form represented the large subunit GP1 that was shed after release of its disulfide linkage to the smaller transmembrane subunit GP2. The minor form were intact GP1,2 complexes incorporated into virosomes. Vector-expressed GP formed spikes morphologically indistinguishable from spikes on virus particles, indicating that spike assembly is independent of other viral proteins. Analysis of a truncation mutant revealed an early and almost complete release of GP1,2 molecules, showing that membrane anchoring is mediated by the carboxy-terminal hydrophobic domain of GP2. We have also compared wild-type virus which requires transcriptional editing for synthesis of full-length GP with a variant that does not depend on editing. Both viruses released comparable amounts of GP1, but the variant expressed only minute amounts of the small, soluble GP which is the expression product of nonedited mRNA species of the GP gene. The abundant shedding of soluble GP1 may play an important role in the immunopathology of Ebola hemorrhagic fever in experimentally and naturally infected hosts.
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Affiliation(s)
- V E Volchkov
- Institut für Virologie, Philipps-Universität Marburg, Germany.
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49
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Volchkov VE, Feldmann H, Volchkova VA, Klenk HD. Processing of the Ebola virus glycoprotein by the proprotein convertase furin. Proc Natl Acad Sci U S A 1998; 95:5762-7. [PMID: 9576958 PMCID: PMC20453 DOI: 10.1073/pnas.95.10.5762] [Citation(s) in RCA: 373] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the present study, we have investigated processing and maturation of the envelope glycoprotein (GP) of Ebola virus. When GP expressed from vaccinia virus vectors was analyzed by pulse-chase experiments, the mature form and two different precursors were identified. First, the endoplasmic reticulum form preGPer, full-length GP with oligomannosidic N-glycans, was detected. preGPer (110 kDa) was replaced by the Golgi-specific form preGP (160 kDa), full-length GP containing mature carbohydrates. preGP was finally converted by proteolysis into mature GP1,2, which consisted of two disulfide-linked cleavage products, the amino-terminal 140-kDa fragment GP1, and the carboxyl-terminal 26-kDa fragment GP2. GP1,2 was also identified in Ebola virions. Studies employing site-directed mutagenesis revealed that GP was cleaved at a multibasic amino acid motif located at positions 497 to 501 of the ORF. Cleavage was blocked by a peptidyl chloromethylketone containing such a motif. GP is cleaved by the proprotein convertase furin. This was indicated by the observation that cleavage did not occur when GP was expressed in furin-defective LoVo cells but that it was restored in these cells by vector-expressed furin. The Reston subtype, which differs from all other Ebola viruses by its low human pathogenicity, has a reduced cleavability due to a mutation at the cleavage site. As a result of these observations, it should now be considered that proteolytic processing of GP may be an important determinant for the pathogenicity of Ebola virus.
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Affiliation(s)
- V E Volchkov
- Institut für Virologie, Philipps-Universität Marburg, 35011 Marburg, Germany.
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Sanchez A, Trappier SG, Ströher U, Nichol ST, Bowen MD, Feldmann H. Variation in the glycoprotein and VP35 genes of Marburg virus strains. Virology 1998; 240:138-46. [PMID: 9448698 PMCID: PMC7172989 DOI: 10.1006/viro.1997.8902] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Marburg virus, the prototype of the family Filoviridae, differs genetically, serologically, and morphologically from Ebola viruses. To better define the genetic variation within the species, VP35 and glycoprotein (GP) genes of representative human isolates from four known episodes of Marburg virus hemorrhagic fever were analyzed. The percentage nucleotide differences in the GP gene coding regions of Marburg viruses (0.1-21%) was nearly equal to the percentage amino acid changes (0-23%), while the percentage nucleotide differences in VP35 coding regions (0.3-20.9%) were higher than the percentage amino acid changes (0.9-6.1%), indicating a greater number of nonsynonymous changes occurring in the GP gene. The higher variation in the GP gene and the corresponding protein, especially those changes in the variable middle region of the GP, suggests that the variability may be the result of responses to natural host pressures. Analysis of the GP gene open reading frame shows a nonrandom distribution of nonsynonymous mutations that may indicate positive Darwinian selection is operating within the variable region. A heptad repeat region and an adjoining predicted fusion peptide are found in the C-terminal third of Marburg virus GPs, as has been previously shown for Ebola virus, and are similar to those found in transmembrane glycoproteins of retroviruses, paramyxoviruses, coronaviruses, and influenza viruses. Comparative analyses showed that there are two lineages within the Marburg virus species of filoviruses. The most recent isolate from Kenya (1987) represents a separate genetic lineage within the Marburg virus species (21-23% amino acid difference). However, this lineage likely does not represent a separate Marburg subtype, as the extent of divergence is less than that separating Ebola virus subtypes.
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Affiliation(s)
- A Sanchez
- Special Pathogens Branch, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
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