201
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Amorim JH, Porchia BFMM, Balan A, Cavalcante RCM, da Costa SM, de Barcelos Alves AM, de Souza Ferreira LC. Refolded dengue virus type 2 NS1 protein expressed in Escherichia coli preserves structural and immunological properties of the native protein. J Virol Methods 2010; 167:186-92. [PMID: 20399232 DOI: 10.1016/j.jviromet.2010.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 03/29/2010] [Accepted: 04/08/2010] [Indexed: 11/25/2022]
Abstract
The dengue virus NS1 protein has been shown to be a protective antigen under different experimental conditions but the recombinant protein produced in bacterial expression systems is usually not soluble and loses structural and immunological features of the native viral protein. In the present study, experimental conditions leading to purification and refolding of the recombinant dengue virus type 2 (DENV-2) NS1 protein expressed in Escherichia coli are described. The refolded recombinant protein was recovered as heat-stable soluble dimers with preserved structural features, as demonstrated by spectroscopic methods. In addition, antibodies against epitopes of the NS1 protein expressed in eukaryotic cells recognized the refolded protein expressed in E. coli but not the denatured form or the same protein submitted to a different refolding condition. Collectively, the results demonstrate that the recombinant NS1 protein preserved important conformation and antigenic determinants of the native virus protein and represents a valuable reagent either for the development of vaccines or for diagnostic methods.
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202
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Diamond MS. Mechanisms of evasion of the type I interferon antiviral response by flaviviruses. J Interferon Cytokine Res 2010; 29:521-30. [PMID: 19694536 DOI: 10.1089/jir.2009.0069] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Virus survival and the ability to cause disease in mammalian hosts depend on their ability to avoid recognition and control by the interferon signal transduction and effector pathways. Flaviviruses comprise a large family of nonsegmented positive sense enveloped cytoplasmic RNA viruses, many of which are globally important human pathogens. Although the mechanistic details are still being dissected, new insight has emerged as to how a flavivirus minimizes the antiviral activity of type I interferon (IFN) to establish productive and potentially lethal infection. This review will summarize our current understanding of how mammalian cells recognize flaviviruses to induce an inhibitory IFN response and the countermeasures this group of viruses has evolved to antagonize this response.
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Affiliation(s)
- Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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203
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Avirutnan P, Fuchs A, Hauhart RE, Somnuke P, Youn S, Diamond MS, Atkinson JP. Antagonism of the complement component C4 by flavivirus nonstructural protein NS1. ACTA ACUST UNITED AC 2010; 207:793-806. [PMID: 20308361 PMCID: PMC2856034 DOI: 10.1084/jem.20092545] [Citation(s) in RCA: 209] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The complement system plays an essential protective role in the initial defense against many microorganisms. Flavivirus NS1 is a secreted nonstructural glycoprotein that accumulates in blood, is displayed on the surface of infected cells, and has been hypothesized to have immune evasion functions. Herein, we demonstrate that dengue virus (DENV), West Nile virus (WNV), and yellow fever virus (YFV) NS1 attenuate classical and lectin pathway activation by directly interacting with C4. Binding of NS1 to C4 reduced C4b deposition and C3 convertase (C4b2a) activity. Although NS1 bound C4b, it lacked intrinsic cofactor activity to degrade C4b, and did not block C3 convertase formation or accelerate decay of the C3 and C5 convertases. Instead, NS1 enhanced C4 cleavage by recruiting and activating the complement-specific protease C1s. By binding C1s and C4 in a complex, NS1 promotes efficient degradation of C4 to C4b. Through this mechanism, NS1 protects DENV from complement-dependent neutralization in solution. These studies define a novel immune evasion mechanism for restricting complement control of microbial infection.
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Affiliation(s)
- Panisadee Avirutnan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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204
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Jiang L, Zhou JM, Yin Y, Fang DY, Tang YX, Jiang LF. Selection and identification of B-cell epitope on NS1 protein of dengue virus type 2. Virus Res 2010; 150:49-55. [PMID: 20211209 DOI: 10.1016/j.virusres.2010.02.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/23/2010] [Accepted: 02/24/2010] [Indexed: 11/16/2022]
Abstract
NS1 of dengue virus (DENV) is an important non-structural protein, which plays an important role in DENV replication and dengue infection. In this study, using the phage-displayed peptide library screening method and purified anti-DENV2-NS1 polyclonal antibody immunoglobulin G (IgG) as target, which was generated from the purified recombinant expressed DENV2-NS1 protein immunization on rabbit, seven B-cell epitopes of DENV2-NS1 protein were screened. Considering the results of comprehensive bioinformatic analysis on NS1 B-cell epitopes, possible dominant B-cell epitopes are located in amino acids residues 36-45, 80-89, 103-112, 121-130, 187-196, 295-304, and 315-324 of the NS1, and two epitope-based NS1 protein dodecapeptides corresponding to the predominant epitopes (PA10: (36)PESPSKLASA(45) and AA10: (187)AIKDNRAVHA(196)) were chosen for synthesis. Results of binding assay and competitive-inhibition assays indicated the two peptides were the specific epitopes of DENV2-NS1 protein. These epitopes could be useful in understanding the pathogenesis of DENV and as dengue vaccine constituents in further study.
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Affiliation(s)
- Lan Jiang
- Department of Microbiology, Zhongshan School of Medicine, Sun Yat-Sen University, Zhongshan Road 2, Guangzhou 510080, PR China
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205
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Rumyantsev AA, Zhang ZX, Gao QS, Moretti N, Brown N, Kleanthous H, Delagrave S, Guirakhoo F, Collett MS, Pugachev KV. Direct random insertion of an influenza virus immunologic determinant into the NS1 glycoprotein of a vaccine flavivirus. Virology 2010; 396:329-38. [DOI: 10.1016/j.virol.2009.10.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 10/13/2009] [Accepted: 10/20/2009] [Indexed: 01/19/2023]
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206
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Yusoff NA, Soin N, Rahman NA, Rahman RNZRA, Kahar MA, Ibrahim F. Binding characteristics study for dengue virus non-structural protein 1 of Antigen and its antibody by using circular dichroism technique. 2009 INTERNATIONAL CONFERENCE FOR TECHNICAL POSTGRADUATES (TECHPOS) 2009. [DOI: 10.1109/techpos.2009.5412060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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207
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Avirutnan P, Mehlhop E, Diamond MS. Complement and its role in protection and pathogenesis of flavivirus infections. Vaccine 2009; 26 Suppl 8:I100-7. [PMID: 19388173 PMCID: PMC2768071 DOI: 10.1016/j.vaccine.2008.11.061] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The complement system is a family of serum and cell surface proteins that recognize pathogen-associated molecular patterns, altered-self ligands, and immune complexes. Activation of the complement cascade triggers several antiviral functions including pathogen opsonization and/or lysis, and priming of adaptive immune responses. In this review, we will examine the role of complement activation in protection and/or pathogenesis against infection by Flaviviruses, with an emphasis on experiments with West Nile and Dengue viruses.
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Affiliation(s)
- Panisadee Avirutnan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, United States
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208
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McBride WJH. Evaluation of dengue NS1 test kits for the diagnosis of dengue fever. Diagn Microbiol Infect Dis 2009; 64:31-6. [DOI: 10.1016/j.diagmicrobio.2009.01.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/27/2008] [Accepted: 01/07/2009] [Indexed: 10/21/2022]
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209
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Virus-specific cytolytic antibodies to nonstructural protein 1 of Japanese encephalitis virus effect reduction of virus output from infected cells. J Virol 2009; 83:4766-77. [PMID: 19264772 DOI: 10.1128/jvi.01850-08] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We demonstrate the presence of nonstructural protein 1 (NS1)-specific antibodies in a significant proportion of convalescent-phase human serum samples obtained from a cohort in an area where Japanese encephalitis virus (JEV) is endemic. Sera containing antibodies to NS1 but not those with antibodies to other JEV proteins, such as envelope, brought about complement-mediated lysis of JEV-infected BHK-21 cells. Target cells infected with a recombinant poxvirus expressing JEV NS1 on the cell surface confirmed the NS1 specificity of cytolytic antibodies. Mouse anti-NS1 cytolytic sera caused a complement-dependent reduction in virus output from infected human cells, demonstrating their important role in viral control. Antibodies elicited by JEV NS1 did not cross lyse West Nile virus- or dengue virus-infected cells despite immunoprecipitating the NS1 proteins of these related flaviviruses. Additionally, JEV NS1 failed to bind complement factor H, in contrast to NS1 of West Nile virus, suggesting that the NS1 proteins of different flaviviruses have distinctly different mechanisms for interacting with the host. Our results also point to an important role for JEV NS1-specific human immune responses in protection against JE and provide a strong case for inclusion of the NS1 protein in next generation of JEV vaccines.
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210
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Das D, Mongkolaungkoon S, Suresh MR. Super induction of dengue virus NS1 protein in E. coli. Protein Expr Purif 2009; 66:66-72. [PMID: 19232392 PMCID: PMC7129434 DOI: 10.1016/j.pep.2009.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 01/30/2009] [Accepted: 02/05/2009] [Indexed: 12/28/2022]
Abstract
The non-structural protein 1 (NS1) of dengue virus is a useful target for diagnostics of dengue infection since the protein is abundantly circulating in blood during the acute phase of the disease. Prior work has established that secreted NS1 levels in plasma correlates with viremia levels and hence can also be used to diagnose patients at the risk for developing dengue hemorrhagic fever. Thus detection of non-structural dengue antigens may be of benefit for an early rapid diagnosis of dengue infection due to its long half life in the blood. Here we describe a simple and efficient method for the expression of NS1 in Escherichia coli, which could potentially be used to develop monoclonal and bispecific antibodies for point of care diagnostics. E. coli codon optimized synthetic full-length NS1 gene of dengue serotype 1 (DEN-1) was successfully cloned and expressed in very high-level as inclusion bodies. The NS1 protein was successfully affinity purified and refolded as a recombinant NS1 (rNS1) protein in E. coli and yield was 230–250 mg/L of bacterial culture. The rNS1 protein was used to immunize mice for hybridoma development. The polyclonal antiserum from animals immunized with this rNS1 protein was found to specifically recognize the rNS1, thus demonstrating the immunogenic nature of the protein. The rNS1 protein purified from E. coli could be useful for developing a sensitive serum diagnostic assay to monitor dengue outbreaks.
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Affiliation(s)
- Dipankar Das
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 11304-89 Avenue, Edmonton, Alberta, Canada
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211
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Proteomic Analysis of Endothelial Cell Autoantigens Recognized by Anti-Dengue Virus Nonstructural Protein 1 Antibodies. Exp Biol Med (Maywood) 2009; 234:63-73. [DOI: 10.3181/0805-rm-147] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We previously showed the occurrence of autoimmune responses in dengue virus (DV) infection, which has potential implications for the pathogenesis of dengue hemorrhagic syndrome. In the present study, we have used a proteomic analysis to identify several candidate proteins on HMEC-1 endothelial cells recognized by anti-DV nonstructural protein 1 (NS1) antibodies. The target proteins, including ATP synthase β chain, protein disulfide isomerase, vimentin, and heat shock protein 60, co-localize with anti-NS1 binding sites on nonfixed HMEC-1 cells using immunohistochemical double staining and confocal microscopy. The cross-reactivity of anti-target protein antibodies with HMEC-1 cells was inhibited by NS1 protein pre-absorption. Furthermore, a cross-reactive epitope on NS1 amino acid residues 311–330 (P311–330) was predicted using homologous sequence alignment. The reactivity of dengue hemorrhagic patient sera with HMEC-1 cells was blocked by synthetic peptide P311–330 pre-absorption. Taken together, our results identify putative targets on endothelial cells recognized by anti-DV NS1 antibodies, where NS1 P311–330 possesses the shared epitope.
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212
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Zainah S, Wahab AHA, Mariam M, Fauziah MK, Khairul AH, Roslina I, Sairulakhma A, Kadimon SS, Jais MSM, Chua KB. Performance of a commercial rapid dengue NS1 antigen immunochromatography test with reference to dengue NS1 antigen-capture ELISA. J Virol Methods 2008; 155:157-60. [PMID: 19022293 DOI: 10.1016/j.jviromet.2008.10.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 10/15/2008] [Accepted: 10/20/2008] [Indexed: 11/19/2022]
Abstract
The performance of a commercial immunochromatography test for rapid detection of dengue NS1 antigen present in serum or plasma of patients was evaluated against a commercial dengue NS1 antigen-capture ELISA. The rapid immunochromatography test gave an overall sensitivity of 90.4% with a specificity of 99.5%. The sensitivity was highest for serum samples from which virus was isolated (96.3%) and lowest for those from which virus was not isolated and RT-PCR was negative (76.4%). The sensitivity was significantly higher for serum samples from patients with acute primary dengue (92.3%) than those from patients with acute secondary dengue (79.1%). The positive predictive value and negative predictive value of this commercial immunochromatography test were 99.6% and 87.9% respectively.
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Affiliation(s)
- S Zainah
- Virology Unit, Infectious Disease Research Centre, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia.
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213
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Secretome of HepG2 cells infected with dengue virus: Implications for pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1607-16. [DOI: 10.1016/j.bbapap.2008.06.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 05/27/2008] [Accepted: 06/11/2008] [Indexed: 11/21/2022]
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214
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Noisakran S, Dechtawewat T, Avirutnan P, Kinoshita T, Siripanyaphinyo U, Puttikhunt C, Kasinrerk W, Malasit P, Sittisombut N. Association of dengue virus NS1 protein with lipid rafts. J Gen Virol 2008; 89:2492-2500. [PMID: 18796718 DOI: 10.1099/vir.0.83620-0] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
During the replication of dengue virus, a viral non-structural glycoprotein, NS1, associates with the membrane on the cell surface and in the RNA replication complex. NS1 lacks a transmembrane domain, and the mechanism by which it associates with the membrane remains unclear. This study aimed to investigate whether membrane-bound NS1 is present in lipid rafts in dengue virus-infected cells. Double immunofluorescence staining of infected HEK-293T cells revealed that NS1 localized with raft-associated molecules, ganglioside GM1 and CD55, on the cell surface. In a flotation gradient centrifugation assay, a small proportion of NS1 in Triton X-100 cell lysate consistently co-fractionated with raft markers. Association of NS1 with lipid rafts was detected for all four dengue serotypes, as well as for Japanese encephalitis virus. Analysis of recombinant NS1 forms showed that glycosylated NS1 dimers stably expressed in HEK-293T cells without an additional C-terminal sequence, or with a heterologous transmembrane domain, failed to associate with lipid rafts. In contrast, glycosylphosphatidylinositol-linked recombinant NS1 exhibited a predilection for lipid rafts. These results indicate an association of a minor subpopulation of NS1 with lipid rafts during dengue virus infection and suggest that modification of NS1, possibly lipidation, is required for raft association.
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Affiliation(s)
- Sansanee Noisakran
- Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand
| | - Thanyaporn Dechtawewat
- Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Panisadee Avirutnan
- Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Taroh Kinoshita
- Department of Immunoregulation, Research Institute of Microbial Diseases, Osaka University, Osaka, Japan
| | - Uamporn Siripanyaphinyo
- Thailand-Japan Research Collaboration Center on Emerging and Re-Emerging Infections (RCC-ERI), Nonthaburi 11000, Thailand
| | - Chunya Puttikhunt
- Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand
| | - Watchara Kasinrerk
- Department of Clinical Immunology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand
| | - Prida Malasit
- Medical Molecular Biology Unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand
| | - Nopporn Sittisombut
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand
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215
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Tung YC, Lin KH, Chiang HC, Ke LY, Chen YH, Ke GM, Chen TC, Chou LC, Lu PL. Molecular Epidemiology of Dengue Virus Serotype 2 in the Taiwan 2002 Outbreak With Envelope Gene and Nonstructural Protein 1 Gene Analysis. Kaohsiung J Med Sci 2008; 24:398-407. [DOI: 10.1016/s1607-551x(08)70163-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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216
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Perera R, Kuhn RJ. Structural proteomics of dengue virus. Curr Opin Microbiol 2008; 11:369-77. [PMID: 18644250 DOI: 10.1016/j.mib.2008.06.004] [Citation(s) in RCA: 285] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 06/02/2008] [Accepted: 06/19/2008] [Indexed: 12/13/2022]
Abstract
In this paper, we discuss recent advances in our knowledge of the dengue virus life cycle based on new structural data of the virus and its proteins. Specifically, we focus on the structure of the pre-membrane protein, prM and its role in virus assembly, the first full-length structure of a multi-domain dengue virus replication protein, NS3, and the recently solved structures of NS5 methyltransferase and polymerase domains. These structures provide a basis for describing function and predicting putative host interactions.
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Affiliation(s)
- Rushika Perera
- Markey Center for Structural Biology & Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, United States
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217
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Noisakran S, Sengsai S, Thongboonkerd V, Kanlaya R, Sinchaikul S, Chen ST, Puttikhunt C, Kasinrerk W, Limjindaporn T, Wongwiwat W, Malasit P, Yenchitsomanus PT. Identification of human hnRNP C1/C2 as a dengue virus NS1-interacting protein. Biochem Biophys Res Commun 2008; 372:67-72. [PMID: 18471994 DOI: 10.1016/j.bbrc.2008.04.165] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 04/28/2008] [Indexed: 01/24/2023]
Abstract
Dengue virus nonstructural protein 1 (NS1) is a key glycoprotein involved in the production of infectious virus and the pathogenesis of dengue diseases. Very little is known how NS1 interacts with host cellular proteins and functions in dengue virus-infected cells. This study aimed at identifying NS1-interacting host cellular proteins in dengue virus-infected cells by employing co-immunoprecipitation, two-dimensional gel electrophoresis, and mass spectrometry. Using lysates of dengue virus-infected human embryonic kidney cells (HEK 293T), immunoprecipitation with an anti-NS1 monoclonal antibody revealed eight isoforms of dengue virus NS1 and a 40-kDa protein, which was subsequently identified by quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) as human heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2. Further investigation by co-immunoprecipitation and co-localization confirmed the association of hnRNP C1/C2 and dengue virus NS1 proteins in dengue virus-infected cells. Their interaction may have implications in virus replication and/or cellular responses favorable to survival of the virus in host cells.
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Affiliation(s)
- Sansanee Noisakran
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand
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218
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Ludert JE, Mosso C, Ceballos-Olvera I, del Angel RM. Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells. Virol J 2008; 5:51. [PMID: 18439289 PMCID: PMC2386455 DOI: 10.1186/1743-422x-5-51] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 04/25/2008] [Indexed: 11/25/2022] Open
Abstract
Current methods for dengue virus quantitation are either time consuming, technically demanding or costly. As an alternative, the commercial enzyme immunoassay Platelia™ Dengue NS1 AG (Bio-Rad Laboratories) was used to monitor semiquantitatively dengue virus replication in cultured cells. The presence of NS1 protein was evaluated in supernatants from Vero and C6/36 HT cells infected with dengue virus. The amount of NS1 detected in the supernatants of infected cells was proportional to the initial MOI used and to the time of post infection harvest. This immunoassay was also able to detect the presence of NS1 in the supernatants of infected human macrophages. Inhibition of dengue virus replication in C6/36 HT cells treated with lysosomotropic drugs was readily monitored with the use of this assay. These results suggest that the Platelia™ Dengue NS1 AG kit can be used as a fast and reliable surrogate method for the relative quantitation of dengue virus replication in cultured cells.
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Affiliation(s)
- Juan E Ludert
- Departamento de Patología Experimental, Centro de Investigación y de Estudios Avanzados del I.P.N. , Mexico City, Mexico.
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219
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Tajima S, Takasaki T, Kurane I. Characterization of Asn130-to-Ala mutant of dengue type 1 virus NS1 protein. Virus Genes 2008; 36:323-9. [PMID: 18288598 DOI: 10.1007/s11262-008-0211-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 01/28/2008] [Indexed: 11/26/2022]
Abstract
The nonstructural protein 1 (NS1) of flavivirus has two N-glycosylation sites that are thought to be important for viral replication. Effects of NS1 glycosylation site mutations on viral replication have been reported in several flaviviruses, but the results have differed. In this report, we examined the role of glycosylation site of NS1 on the replication of dengue type 1 virus (DENV-1). DENV-1 production was not detectable when full-length DENV-1 RNA, which has an N-glycosylation site Asn130-to-Ala (Asn130Ala) mutation in NS1, was transfected into mammalian and mosquito cells. However, replication and secretion of recombinant DENV-1 with the NS1 Asn130Ala mutation were recovered by exogenously expressed wild-type DENV-1 NS1. A growth kinetics experiment showed that propagation of wild-type DENV-1 was prevented by NS1 Asn130Ala mutant expression in trans. Our results suggest that Asn130 of the DENV-1 NS1 is important for viral replication in both mammalian and mosquito cells.
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Affiliation(s)
- Shigeru Tajima
- Laboratory of Vector Borne Viruses, Department of Virology 1, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan.
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220
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Avirutnan P, Zhang L, Punyadee N, Manuyakorn A, Puttikhunt C, Kasinrerk W, Malasit P, Atkinson JP, Diamond MS. Secreted NS1 of dengue virus attaches to the surface of cells via interactions with heparan sulfate and chondroitin sulfate E. PLoS Pathog 2008; 3:e183. [PMID: 18052531 PMCID: PMC2092380 DOI: 10.1371/journal.ppat.0030183] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 10/19/2007] [Indexed: 12/02/2022] Open
Abstract
Dengue virus (DENV) nonstructural protein-1 (NS1) is a secreted glycoprotein that is absent from viral particles but accumulates in the supernatant and on the plasma membrane of cells during infection. Immune recognition of cell surface NS1 on endothelial cells has been hypothesized as a mechanism for the vascular leakage that occurs during severe DENV infection. However, it has remained unclear how NS1 becomes associated with the plasma membrane, as it contains no membrane-spanning sequence motif. Using flow cytometric and ELISA-based binding assays and mutant cell lines lacking selective glycosaminoglycans, we show that soluble NS1 binds back to the surface of uninfected cells primarily via interactions with heparan sulfate and chondroitin sulfate E. DENV NS1 binds directly to the surface of many types of epithelial and mesenchymal cells yet attaches poorly to most peripheral blood cells. Moreover, DENV NS1 preferentially binds to cultured human microvascular compared to aortic or umbilical cord vein endothelial cells. This binding specificity was confirmed in situ as DENV NS1 bound to lung and liver but not intestine or brain endothelium of mouse tissues. Differential binding of soluble NS1 by tissue endothelium and subsequent recognition by anti-NS1 antibodies could contribute to the selective vascular leakage syndrome that occurs during severe secondary DENV infection. Dengue virus (DENV) is a mosquito-transmitted virus that infects humans and has become a global emerging infectious disease threat. Four serotypes of DENV exist, and the most severe cases are associated with secondary infection with a different virus serotype. Clinical deterioration is characterized by bleeding and selective vascular leakage from endothelium in specific tissue sites. An increased understanding of how DENV proteins contribute to this phenotype is vital to developing novel vaccines and identifying individuals at risk for severe disease. DENV nonstructural protein-1 (NS1) is one such protein: during infection, it is secreted and accumulates in the supernatant and on the surface of cells. In this study, we demonstrate that soluble DENV NS1 attaches to subsets of cells, including some but not all endothelial cells, primarily via an interaction with specific glycosaminoglycans (heparan sulfate and chondroitin sulfate E). This was confirmed in tissue binding studies as DENV NS1 bound to lung and liver but not intestine or brain endothelium. Our findings suggest that the selective vascular leakage that occurs in severe DENV infection may be related to the relative ability of endothelial cells in different tissues to bind soluble NS1 and to be targeted by cross-reactive anti-NS1 antibodies during secondary infection.
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Affiliation(s)
- Panisadee Avirutnan
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Medical Molecular Biology Unit, Office for Research and Development, Mahidol University, Bangkok, Thailand
| | - Lijuan Zhang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Nuntaya Punyadee
- Medical Molecular Biology Unit, Office for Research and Development, Mahidol University, Bangkok, Thailand
| | - Ananya Manuyakorn
- Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chunya Puttikhunt
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology BIOTEC, National Science and Technology Development Agency NSTDA, Pathumthani, Thailand
| | - Watchara Kasinrerk
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology BIOTEC, National Science and Technology Development Agency NSTDA, Pathumthani, Thailand
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Prida Malasit
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology BIOTEC, National Science and Technology Development Agency NSTDA, Pathumthani, Thailand
| | - John P Atkinson
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * To whom correspondence should be addressed. E-mail:
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221
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Lapphra K, Sangcharaswichai A, Chokephaibulkit K, Tiengrim S, Piriyakarnsakul W, Chakorn T, Yoksan S, Wattanamongkolsil L, Thamlikitkul V. Evaluation of an NS1 antigen detection for diagnosis of acute dengue infection in patients with acute febrile illness. Diagn Microbiol Infect Dis 2008; 60:387-91. [PMID: 18191361 DOI: 10.1016/j.diagmicrobio.2007.11.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 11/13/2007] [Accepted: 11/14/2007] [Indexed: 10/22/2022]
Abstract
Diagnosis of dengue infection during the febrile stage has been challenging. We evaluated the accuracy of NS1 protein detection in diagnosing dengue infection in patients presenting with acute febrile illness in Bangkok, Thailand. Of the 235 subjects presented with fever of unknown source within 5 days, 132 (56.2%) were male with the median age of 17.8 (range, 3-52) years. The median duration of fever was 4 (range, 1-5) days. One hundred seventy-one (72.8%) patients had dengue infection, of which 158 (92.4%) were secondary infections. The sensitivity of NS1 Ag test was 63.2% (95% confidence interval [CI], 55.7-70.0), and the specificity was 98.4% (95% CI, 91.7-99.7). The positive and negative predictive values were 99.0% and 52.5%, respectively. The immune complex dissociation by acid treatment increase sensitivity from 63.2% to 72%. In an endemic area, Plateliatrade mark NS1 Ag test has limited sensitivity but very high specificity for diagnosis of dengue infection in patients with acute febrile illness.
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Affiliation(s)
- Keswadee Lapphra
- Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
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222
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Kurosu T, Chaichana P, Yamate M, Anantapreecha S, Ikuta K. Secreted complement regulatory protein clusterin interacts with dengue virus nonstructural protein 1. Biochem Biophys Res Commun 2007; 362:1051-6. [PMID: 17825259 DOI: 10.1016/j.bbrc.2007.08.137] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 08/19/2007] [Indexed: 12/14/2022]
Abstract
Vascular leakage and shock are the major causes of death in patients with dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). It has been suggested that patients with an elevated level of the free soluble form of dengue virus (DV) nonstructural protein 1 (sNS1) are at risk of developing DHF. To understand the role of sNS1 in blood, we searched for the host molecule with which NS1 interacts in human plasma by affinity purification using a GST-fused NS1. Complement inhibitory factor clusterin (Clu), which naturally inhibits the formation of terminal complement complex (TCC), was identified by mass spectrometry. A recombinant sNS1 produced from 293T cells and sNS1 from DV-infected Vero cells interacted with human Clu. Since an activated complement system reportedly causes vascular leakage, the interaction between sNS1 and Clu may contribute to the progression of DHF.
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Affiliation(s)
- Takeshi Kurosu
- Research Collaboration Center on Emerging and Re-emerging Infections (RCC-ERI), Tiwanon Rd, Muang, Nonthaburi 11000, Thailand.
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223
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Chung KM, Thompson BS, Fremont DH, Diamond MS. Antibody recognition of cell surface-associated NS1 triggers Fc-gamma receptor-mediated phagocytosis and clearance of West Nile Virus-infected cells. J Virol 2007; 81:9551-5. [PMID: 17582005 PMCID: PMC1951387 DOI: 10.1128/jvi.00879-07] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have suggested that monoclonal antibodies (MAbs) to flavivirus nonstructural protein-1 (NS-1) protect against infection in mice through an Fc-gamma receptor-dependent pathway. To identify a specific mechanism, we evaluated the protective activity of anti-NS1 MAbs to WNV using mice and cells with deficiencies of specific Fc-gamma receptors. Our results suggest that only MAbs that recognize cell surface-associated NS1 trigger Fc-gamma receptor I- and/or IV-mediated phagocytosis and clearance of WNV-infected cells. These findings may be relevant for generating novel therapeutic MAbs or vaccines against flaviviruses that target the NS1 protein.
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Affiliation(s)
- Kyung Min Chung
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
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224
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Clark DC, Lobigs M, Lee E, Howard MJ, Clark K, Blitvich BJ, Hall RA. In situ reactions of monoclonal antibodies with a viable mutant of Murray Valley encephalitis virus reveal an absence of dimeric NS1 protein. J Gen Virol 2007; 88:1175-1183. [PMID: 17374761 DOI: 10.1099/vir.0.82609-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Studies on the NS1 protein of flaviviruses have concluded that formation of a stable homodimer is required for virus replication. However, previous work has reported that substitution of a conserved proline by leucine at residue 250 in NS1 of Kunjin virus (KUNV) eliminated dimerization, but allowed virus replication to continue. To assess whether this substitution has similar effects on other flaviviruses, it was introduced into an infectious clone of Murray Valley encephalitis virus (MVEV). Consistent with studies of KUNV, the mutant virus (MVEV(NS1-250Leu)) produced high levels of monomeric NS1 and the NS1 homodimer could not be detected. In contrast, wild-type MVEV cultures contained predominantly dimeric NS1. Retarded virus growth in Vero cells and loss of neuroinvasiveness for weanling mice revealed further similarities between MVEV(NS1-250Leu) and the corresponding KUNV mutant. To confirm that the lack of detection of dimeric NS1 in mutant virus samples was not due to denaturation of unstable dimers during Western blotting, a mAb (2E3) specific for the MVEV NS1 homodimer was produced. When NS1 protein was fixed in situ in mammalian and arthropod cells infected with wild-type or mutant virus, 2E3 reacted strongly with the former, but not the latter. These results confirmed that Pro(250) in NS1 is important for dimerization and that substitution of this residue by leucine represents a conserved marker of attenuation for viruses of the Japanese encephalitis virus serocomplex. The inability to detect dimeric NS1 in supernatant or cell monolayers of cultures productively infected with mutant virus also suggests that dimerization of the protein may not be essential for virus replication.
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MESH Headings
- Amino Acid Substitution
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Viral/immunology
- Antibodies, Viral/metabolism
- Arthropods
- Chlorocebus aethiops
- Dimerization
- Disease Models, Animal
- Encephalitis Virus, Murray Valley/genetics
- Encephalitis Virus, Murray Valley/immunology
- Encephalitis Virus, Murray Valley/pathogenicity
- Encephalitis Virus, Murray Valley/physiology
- Encephalitis, Arbovirus/virology
- Flavivirus
- Mice
- Mutagenesis, Site-Directed
- Vero Cells
- Viral Nonstructural Proteins/chemistry
- Viral Nonstructural Proteins/genetics
- Viral Nonstructural Proteins/immunology
- Viral Nonstructural Proteins/metabolism
- Virus Replication
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Affiliation(s)
- David C Clark
- School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Australia
| | - Mario Lobigs
- Division of Immunology and Cell Biology, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Eva Lee
- Division of Immunology and Cell Biology, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Megan J Howard
- Department of Microbiology, The University of Western Australia, Nedlands, Australia
| | - Kerri Clark
- School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Australia
| | - Bradley J Blitvich
- Department of Microbiology, The University of Western Australia, Nedlands, Australia
| | - Roy A Hall
- School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Australia
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225
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Noisakran S, Dechtawewat T, Rinkaewkan P, Puttikhunt C, Kanjanahaluethai A, Kasinrerk W, Sittisombut N, Malasit P. Characterization of dengue virus NS1 stably expressed in 293T cell lines. J Virol Methods 2007; 142:67-80. [PMID: 17331594 DOI: 10.1016/j.jviromet.2007.01.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 12/29/2006] [Accepted: 01/15/2007] [Indexed: 10/23/2022]
Abstract
Dengue virus NS1 is a viral nonstructural protein detected in sera of infected individuals and in infected cells. Multiple NS1 structural forms have been reported but the functional characteristics of these forms remain unknown. In this study, a set of 293T cell lines stably expressing recombinant dengue NS1 without additional C-terminal sequence (rNS1s), with a heterologous transmembrane segment (rNS1tm), or with the 26-residue N-terminal portion of NS2A (rNS1v1) was established to aid in the characterization of different NS1 forms. Each NS1 protein form had distinct phenotypes and the following properties were documented: (1) dissipated expression in the cytoplasm, dimerization, and N-glycosylation were observed, regardless of the forms of NS1 expressed; (2) the rNS1v1 and rNS1tm forms, but not the rNS1s, were observed prominently on the surface membrane; (3) only the rNS1v1 form incorporated ethanolamine, a precursor of the glycosylphosphatidylinositol moiety, and was partially sensitive to digestion with phosphatidylinositol-specific phospholipase C. The stable 239T transfectants expressing multiple forms of dengue NS1 may be a useful model to investigate the function of NS1 and the mechanism by which NS1 associates with membrane.
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Affiliation(s)
- Sansanee Noisakran
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, Thailand
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226
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Costa SM, Azevedo AS, Paes MV, Sarges FS, Freire MS, Alves AMB. DNA vaccines against dengue virus based on the ns1 gene: The influence of different signal sequences on the protein expression and its correlation to the immune response elicited in mice. Virology 2007; 358:413-23. [PMID: 17020777 DOI: 10.1016/j.virol.2006.08.052] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 08/21/2006] [Accepted: 08/30/2006] [Indexed: 11/23/2022]
Abstract
We analyzed four DNA vaccines based on DENV-2 NS1: pcENS1, encoding the C-terminal from E protein plus the NS1 region; pcENS1ANC, similar to pcENS1 plus the N-terminal sequence from NS2a (ANC); pcTPANS1, coding the t-PA signal sequence fused to NS1; and pcTPANS1ANC, similar to pcTPANS1 plus the ANC sequence. The NS1 was detected in lysates and culture supernatants from pcTPANS1-, pcENS1- and pcENS1ANC-transfected cells and not in cells with pcTPANS1ANC. Only the pcENS1ANC leads the expression of NS1 in plasma membrane, confirming the importance of ANC sequence for targeting NS1 to cell surface. High levels of antibodies recognizing conformational epitopes of NS1 were induced in mice immunized with pcTPANS1 and pcENS1, while only few pcENS1ANC-inoculated animals presented detectable anti-NS1 IgG. Protection against DENV-2 was verified in pcTPANS1- and pcENS1-immunized mice, although the plasmid pcTPANS1 induced slight higher protective immunity. These plasmids seem to activate distinct patterns of the immune system.
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Affiliation(s)
- S M Costa
- Laboratory of Immunopathology, Department of Bichemistry and Molecular Biology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Av. Brasil 4365, Pav. Leonidas Deane, s. 204, Rio de Janeiro, RJ, CEP 21040-900, Brazil
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227
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Schlesinger JJ. Flavivirus nonstructural protein NS1: complementary surprises. Proc Natl Acad Sci U S A 2006; 103:18879-80. [PMID: 17146046 PMCID: PMC1748143 DOI: 10.1073/pnas.0609522103] [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: 11/18/2022] Open
Affiliation(s)
- Jacob J. Schlesinger
- Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
- *E-mail:
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228
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Kumarasamy V, Wahab AHA, Chua SK, Hassan Z, Chem YK, Mohamad M, Chua KB. Evaluation of a commercial dengue NS1 antigen-capture ELISA for laboratory diagnosis of acute dengue virus infection. J Virol Methods 2006; 140:75-9. [PMID: 17140671 DOI: 10.1016/j.jviromet.2006.11.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2006] [Revised: 10/28/2006] [Accepted: 11/02/2006] [Indexed: 11/25/2022]
Abstract
A commercial dengue NS1 antigen-capture ELISA was evaluated to demonstrate its potential application for early laboratory diagnosis of acute dengue virus infection. Dengue virus NS1 antigen was detected in 199 of 213 acute serum samples from patients with laboratory confirmation of acute dengue virus infection but none of the 354 healthy blood donors' serum specimens. The dengue NS1 antigen-capture ELISA gave an overall sensitivity of 93.4% (199/213) and a specificity of 100% (354/354). The sensitivity was significantly higher in acute primary dengue (97.3%) than in acute secondary dengue (70.0%). The positive predictive value of the dengue NS1 antigen-capture ELISA was 100% and negative predictive value was 97.3%. Comparatively, virus isolation gave an overall positive isolation rate of 68.1% with a positive isolation rate of 73.9 and 31.0% for acute primary dengue and acute secondary dengue, respectively. Molecular detection of dengue RNA by RT-PCR gave an overall positive detection rate of 66.7% with a detection rate of 65.2 and 75.9% for acute primary dengue and acute secondary dengue, respectively. The results indicate that the commercial dengue NS1 antigen-capture ELISA may be superior to virus isolation and RT-PCR for the laboratory diagnosis of acute dengue infection based on a single serum sample.
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Affiliation(s)
- V Kumarasamy
- Makmal Kesihatan Awam Kebangsaan (National Public Health Laboratory), Kementerian Kesihatan, Lot 1853 Kg. Melayu, 47000 Sungai Buloh, Selangor, Malaysia
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229
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Umareddy I, Chao A, Sampath A, Gu F, Vasudevan SG. Dengue virus NS4B interacts with NS3 and dissociates it from single-stranded RNA. J Gen Virol 2006; 87:2605-2614. [PMID: 16894199 DOI: 10.1099/vir.0.81844-0] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dengue virus, a member of the family Flaviviridae of positive-strand RNA viruses, has seven non-structural proteins: NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5. Except for enzymic activities contained within NS3 and NS5, the roles of the other proteins in virus replication and pathogenesis are not well defined. In this study, a physical interaction between NS4B and the helicase domain of NS3 was identified by using a yeast two-hybrid assay. This interaction was further confirmed by biochemical pull-down and immunoprecipitation assays, both with purified proteins and with dengue virus-infected cell lysates. NS4B co-localized with NS3 in the perinuclear region of infected human cells. Furthermore, NS4B dissociated NS3 from single-stranded RNA and consequently enhanced the helicase activity of NS3 in an in vitro unwinding assay. These results suggest that NS4B modulates dengue virus replication via its interaction with NS3.
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Affiliation(s)
- Indira Umareddy
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670
| | - Alex Chao
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670
| | - Aruna Sampath
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670
| | - Feng Gu
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670
| | - Subhash G Vasudevan
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos Building, Singapore 138670
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230
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Chung KM, Nybakken GE, Thompson BS, Engle MJ, Marri A, Fremont DH, Diamond MS. Antibodies against West Nile Virus nonstructural protein NS1 prevent lethal infection through Fc gamma receptor-dependent and -independent mechanisms. J Virol 2006; 80:1340-51. [PMID: 16415011 PMCID: PMC1346945 DOI: 10.1128/jvi.80.3.1340-1351.2006] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 11/11/2005] [Indexed: 11/20/2022] Open
Abstract
The flavivirus nonstructural protein NS1 is a highly conserved secreted glycoprotein that does not package with the virion. Immunization with NS1 elicits a protective immune response against yellow fever, dengue, and tick-borne encephalitis flaviviruses through poorly defined mechanisms. In this study, we purified a recombinant, secreted form of West Nile virus (WNV) NS1 glycoprotein from baculovirus-infected insect cells and generated 22 new NS1-specific monoclonal antibodies (MAbs). By performing competitive binding assays and expressing truncated NS1 proteins on the surface of yeast (Saccharomyces cerevisiae) and in bacteria, we mapped 21 of the newly generated MAbs to three NS1 fragments. Prophylaxis of C57BL/6 mice with any of four MAbs (10NS1, 14NS1, 16NS1, and 17NS1) strongly protected against lethal WNV infection (75 to 95% survival, respectively) compared to saline-treated controls (17% survival). In contrast, other anti-NS1 MAbs of the same isotype provided no significant protection. Notably, 14NS1 and 16NS1 also demonstrated marked efficacy as postexposure therapy, even when administered as a single dose 4 days after infection. Virologic analysis showed that 17NS1 protects at an early stage in infection through a C1q-independent and Fc gamma receptor-dependent pathway. Interestingly, 14NS1, which maps to a distinct region on NS1, protected through a C1q- and Fc gamma receptor-independent mechanism. Overall, our data suggest that distinct regions of NS1 can elicit protective humoral immunity against WNV through different mechanisms.
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Affiliation(s)
- Kyung Min Chung
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, Campus Box 8051, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
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231
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Macdonald J, Tonry J, Hall RA, Williams B, Palacios G, Ashok MS, Jabado O, Clark D, Tesh RB, Briese T, Lipkin WI. NS1 protein secretion during the acute phase of West Nile virus infection. J Virol 2006; 79:13924-33. [PMID: 16254328 PMCID: PMC1280181 DOI: 10.1128/jvi.79.22.13924-13933.2005] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The West Nile virus (WNV) nonstructural protein NS1 is a protein of unknown function that is found within, associated with, and secreted from infected cells. We systematically investigated the kinetics of NS1 secretion in vitro and in vivo to determine the potential use of this protein as a diagnostic marker and to analyze NS1 secretion in relation to the infection cycle. A sensitive antigen capture enzyme-linked immunosorbent assay (ELISA) for detection of WNV NS1 (polyclonal-ACE) was developed, as well as a capture ELISA for the specific detection of NS1 multimers (4G4-ACE). The 4G4-ACE detected native NS1 antigens at high sensitivity, whereas the polyclonal-ACE had a higher specificity for recombinant forms of the protein. Applying these assays we found that only a small fraction of intracellular NS1 is secreted and that secretion of NS1 in tissue culture is delayed compared to the release of virus particles. In experimentally infected hamsters, NS1 was detected in the serum between days 3 and 8 postinfection, peaking on day 5, the day prior to the onset of clinical disease; immunoglobulin M (IgM) antibodies were detected at low levels on day 5 postinfection. Although real-time PCR gave the earliest indication of infection (day 1), the diagnostic performance of the 4G4-ACE was comparable to that of real-time PCR during the time period when NS1 was secreted. Moreover, the 4G4-ACE was found to be superior in performance to both the IgM and plaque assays during this time period, suggesting that NS1 is a viable early diagnostic marker of WNV infection.
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Affiliation(s)
- Joanne Macdonald
- Jerome L. and Dawn Greene Infectious Disease Laboratory, Department of Epidemiology, Mailman School of Public Health, Columbia University, 722 W. 168th St, Rm. 1801, New York, NY 10032, USA
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232
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Chua JJE, Bhuvanakantham R, Chow VTK, Ng ML. Recombinant non-structural 1 (NS1) protein of dengue-2 virus interacts with human STAT3beta protein. Virus Res 2005; 112:85-94. [PMID: 15878791 DOI: 10.1016/j.virusres.2005.03.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Revised: 03/16/2005] [Accepted: 03/16/2005] [Indexed: 11/29/2022]
Abstract
A combination of yeast two-hybrid library screening, co-immunoprecipitation and immunofluorescence microscopy demonstrated that dengue-2 virus non-structural 1 (NS1) protein can interact with an N-terminally truncated form of human STAT3beta (DeltaN40-STAT3beta) protein. The NS1 protein interacted with the activated STAT3beta protein in vesicle-like structures in the cell cytoplasm. In addition, transfection of dendritic cells with plasmid expressing NS1 protein also resulted in significant induction of tumor necrosis factor-alpha (TNFalpha) and interleukin-6 (IL-6). Since the STAT3beta protein is an acute-phase response factor, its interaction with NS1 protein may influence the pathological changes observed in dengue fever, dengue hemorrhagic fever and dengue shock syndrome.
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Affiliation(s)
- John Jia-En Chua
- Programme in Infectious Diseases and Flavivirology Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, Kent Ridge, Singapore 117597, Singapore
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233
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Alcon-LePoder S, Drouet MT, Roux P, Frenkiel MP, Arborio M, Durand-Schneider AM, Maurice M, Le Blanc I, Gruenberg J, Flamand M. The secreted form of dengue virus nonstructural protein NS1 is endocytosed by hepatocytes and accumulates in late endosomes: implications for viral infectivity. J Virol 2005; 79:11403-11. [PMID: 16103191 PMCID: PMC1193635 DOI: 10.1128/jvi.79.17.11403-11411.2005] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The flavivirus nonstructural protein NS1 is expressed as three discrete species in infected mammalian cells: an intracellular, membrane-associated form essential for viral replication, a cell surface-associated form that may be involved in signal transduction, and a secreted form (sNS1), the biological properties of which remain elusive. To determine the distribution of the dengue virus (DEN) sNS1 protein in vivo, we have analyzed by immunohistological means the tissue tropism of purified DEN sNS1 injected intravenously into adult mice. The sNS1 protein was found predominantly associated with the liver, where hepatocytes appeared to represent a major target cell. We further showed that sNS1 could be efficiently endocytosed by human Huh7 and HepG2 hepatocytes in vitro. After its internalization, the protein was detected intracellularly for at least 48 h without being substantially degraded. Colocalization studies of sNS1 with markers of the endolysosomal compartments revealed that the protein was specifically targeted to lysobisphosphatidic acid-rich structures reminiscent of late endosomes, as confirmed by electron microscopy. Intracellular accumulation of sNS1 in Huh7 cells enhanced the fluid phase uptake of rhodamine-labeled dextran. Furthermore, preincubation of Huh7 cells with sNS1 increased dengue virus production after infection with the homologous strain of DEN-1 virus. Our results demonstrate that the accumulation of DEN sNS1 in the late endosomal compartment of hepatocytes potentializes subsequent dengue virus infection in vitro, raising the possibility that sNS1 may contribute to viral propagation in vivo.
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Affiliation(s)
- Sophie Alcon-LePoder
- U.P. Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, France
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234
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Navarro-Sánchez E, Desprès P, Cedillo-Barrón L. Innate immune responses to dengue virus. Arch Med Res 2005; 36:425-35. [PMID: 16099317 DOI: 10.1016/j.arcmed.2005.04.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Accepted: 04/29/2005] [Indexed: 01/12/2023]
Abstract
Dengue fever/dengue hemorrhagic fever (DF/DHF) has emerged as the most important mosquito-borne viral diseases in tropical areas. The dengue virus (DV) has become endemic in most tropical urban centers throughout the world, and DHF has appeared concomitantly with this expansion. Given the fact that intensity of DV replication during the early times of infection could determine clinical outcomes, which ranges from febrile illness (DF) to life-threatening disease (DHF), it is important to understand the impact of DV infection on innate immunity. Interstitial dendritic cells (DCs) are believed to constitute the first line of the innate host defense against invading DV at the anatomical sites where it replicates after the initial bite by infected mosquito. Early activation of natural killer (NK) cells and type-I interferon-dependent immunity may be also important in limiting viral replication at the early times of dengue infection. The ability of infecting DV to counter the innate antiviral immunity might account for differences in virulence observed between viral strains.
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Affiliation(s)
- Erika Navarro-Sánchez
- Unité des Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, France
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235
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Costa SM, Paes MV, Barreto DF, Pinhão AT, Barth OM, Queiroz JLS, Armôa GRG, Freire MS, Alves AMB. Protection against dengue type 2 virus induced in mice immunized with a DNA plasmid encoding the non-structural 1 (NS1) gene fused to the tissue plasminogen activator signal sequence. Vaccine 2005; 24:195-205. [PMID: 16122850 DOI: 10.1016/j.vaccine.2005.07.059] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Accepted: 07/25/2005] [Indexed: 12/01/2022]
Abstract
Dengue is one of the most important arboviral diseases in humans, and although efforts over the last decades have dealt with the development of a vaccine, this vaccine is not available yet. In order to evaluate the potential of a DNA vaccine based on the non-structural 1 (NS1) protein against dengue virus (DENV), we constructed the pcTPANS1 plasmid which contains the secretory signal sequence derived from human tissue plasminogen activator (t-PA) fused to the full length of the DENV-2 NS1 gene. Results indicate that pcTPANS1 promotes correct expression of NS1 in eukaryotic cells and drives secretion of the recombinant protein to the surrounding medium in a dimeric form. Balb/c mice, intramuscularly inoculated with this plasmid, presented high levels of antibodies, recognizing mainly surface-exposed conformational epitopes present in the NS1 protein expressed by insect cells. Long-term antibody response was observed in animals 56 weeks after the first plasmid inoculation, and a rapid, efficient secondary response was observed after a DNA boost. Vaccinated animals were challenged against DENV-2 in two murine models, based on intracerebral (i.c.) and intraperitoneal (i.p.) virus inoculations, and in both cases, pcTPANS1-immunized mice were protected. Overall, these results provide further support for the use of such a plasmid in a possible approach for the development of a vaccine against DENV.
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Affiliation(s)
- Simone M Costa
- Department of Biochemistry and Molecular Biology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Av. Brazil 4365, Pav. Leonidas Deane, sala 204, Rio de Janeiro, RJ, CEP 21040-900, Brazil
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236
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Lemes EMB, Miagostovicsh MP, Alves AMB, Costa SM, Fillipis AMB, Armoa GRG, Araujo MAV. Circulating human antibodies against dengue NS1 protein: potential of recombinant D2V-NS1 proteins in diagnostic tests. J Clin Virol 2005; 32:305-12. [PMID: 15780810 DOI: 10.1016/j.jcv.2004.08.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Accepted: 08/30/2004] [Indexed: 11/24/2022]
Abstract
The dengue virus (DV) causes one of the most important arthropod-borne human viral diseases throughout the tropical and subtropical countries. However, the morbidity and mortality of DV infections could be reduced with an early hospitalization care and a rapid risk identification of developing the dengue haemorrhagic fever (DHF). The nonstructural glycoprotein 1 (NS1) has been pointed as a reagent for immune-assay diagnostic test optimization. To evaluate this potential, recombinant DV2-NS1 proteins (rNS1) were produced from Escherichia coli (NS1EC) and insect cells (NS1IC) expression. The tests were performed by analysis of a human serum panel reacted against different rNS1 forms. The results demonstrated high correspondence between the DV positive sera and the assay results using native or refolded forms of either NS1IC or NS1EC. Also, the IgG and IgM anti-rNS1 level profiles showed distinct distribution, depending on protein form and disease status. However, the IgM anti-rNS1 reactions did not show sensibility to detect the DV in primary infections. The data obtained from the paired serum samples reactivity comparison suggested a heterogeneous human immune response and absence of correspondence between the IgG and IgM profile levels. Moreover, a patient with negative reference test could be detected by specific IgG anti-rNS1 assays presented here. Therefore, these results sustain the usefulness of dengue nonstructural proteins, in particular the NS1, in diagnostic tests as a complementary reagent.
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Affiliation(s)
- E M B Lemes
- Laboratório de Tecnologia Recombinante, Bio-Manguinhos, FIOCRUZ, Av. Brasil, 4365 Manguinhos, Rio de Janeiro, 21045-900 RJ, Brazil
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237
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Jones CT, Patkar CG, Kuhn RJ. Construction and applications of yellow fever virus replicons. Virology 2005; 331:247-59. [PMID: 15629769 DOI: 10.1016/j.virol.2004.10.034] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2004] [Revised: 06/28/2004] [Accepted: 10/01/2004] [Indexed: 11/18/2022]
Abstract
Subgenomic replicons of yellow fever virus (YFV) were constructed to allow expression of heterologous reporter genes in a replication-dependent manner. Expression of the antibiotic resistance gene neomycin phosphotransferase II (Neo) from one of these YFV replicons allowed selection of a stable population of cells (BHK-REP cells) in which the YFV replicon persistently replicated. BHK-REP cells were successfully used to trans-complement replication-defective YFV replicons harboring large internal deletions within either the NS1 or NS3 proteins. Although replicons with large deletions in either NS1 or NS3 were trans-complemented in BHK-REP, replicons that contained deletions of NS3 were trans-complemented at lower levels. In addition, replicons that retained the N-terminal protease domain of NS3 in cis were trans-complemented with higher efficiency than replicons in which both the protease and helicase domains of NS3 were deleted. To study packaging of YFV replicons, Sindbis replicons were constructed that expressed the YFV structural proteins in trans. Using these Sindbis replicons, both replication-competent and trans-complemented, replication-defective YFV replicons could be packaged into pseudo-infectious particles (PIPs). Although these results eliminate a potential role of either NS1 or full-length NS3 in cis for packaging and assembly of the flavivirus virion, they do not preclude the possibility that these proteins may act in trans during these processes.
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Affiliation(s)
- Christopher T Jones
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907-2054, USA
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238
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Affiliation(s)
- Brett D Lindenbach
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Disease, Rockefeller University, New York, New York 10021, USA
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239
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Keelapang P, Sriburi R, Supasa S, Panyadee N, Songjaeng A, Jairungsri A, Puttikhunt C, Kasinrerk W, Malasit P, Sittisombut N. Alterations of pr-M cleavage and virus export in pr-M junction chimeric dengue viruses. J Virol 2004; 78:2367-81. [PMID: 14963133 PMCID: PMC369205 DOI: 10.1128/jvi.78.5.2367-2381.2004] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2003] [Accepted: 11/07/2003] [Indexed: 12/20/2022] Open
Abstract
During the export of flavivirus particles through the secretory pathway, a viral envelope glycoprotein, prM, is cleaved by the proprotein convertase furin; this cleavage is required for the subsequent rearrangement of receptor-binding E glycoprotein and for virus infectivity. Similar to many furin substrates, prM in vector-borne flaviviruses contains basic residues at positions P1, P2, and P4 proximal to the cleavage site; in addition, a number of charged residues are found at position P3 and between positions P5 and P13 that are conserved for each flavivirus antigenic complex. The influence of additional charged residues on pr-M cleavage and virus replication was investigated by replacing the 13-amino-acid, cleavage-proximal region of a dengue virus (strain 16681) with those of tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), and Japanese encephalitis virus (JEV) and by comparing the resultant chimeric viruses generated from RNA-transfected mosquito cells. Among the three chimeric viruses, cleavage of prM was enhanced to a larger extent in JEVpr/16681 than in YFVpr/16681 but was slightly reduced in TBEVpr/16681. Unexpectedly, JEVpr/16681 exhibited decreased focus size, reduced peak titer, and depressed replication in C6/36, PS, and Vero cell lines. The reduction of JEVpr/16681 multiplication correlated with delayed export of infectious virions out of infected cells but not with changes in specific infectivity. Binding of JEVpr/16681 to immobilized heparin and the heparin-inhibitable infection of cells were not altered. Thus, diverse pr-M junction-proximal sequences of flaviviruses differentially influence pr-M cleavage when tested in a dengue virus prM background. More importantly, greatly enhanced prM cleavability adversely affects dengue virus export while exerting a minimal effect on infectivity. Because extensive changes of charged residues at the pr-M junction, as in JEVpr/16681, were not observed among a large number of dengue virus isolates, these results provide a possible mechanism by which the sequence conservation of the pr-M junction of dengue virus is maintained in nature.
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Affiliation(s)
- Poonsook Keelapang
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10400, USA
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240
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Wallis TP, Huang CY, Nimkar SB, Young PR, Gorman JJ. Determination of the disulfide bond arrangement of dengue virus NS1 protein. J Biol Chem 2004; 279:20729-41. [PMID: 14981082 DOI: 10.1074/jbc.m312907200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 12 half-cystines of NS1 proteins are absolutely conserved among flaviviruses, suggesting their importance to the structure and function of these proteins. In the present study, peptides from recombinant Dengue-2 virus NS1 were produced by tryptic digestion in 100% H(2)(16)O, peptic digestion in 50% H(2)(18)O, thermolytic digestion in 50% H(2)(18)O, or combinations of these digestion conditions. Peptides were separated by size exclusion and/or reverse phase high performance liquid chromatography and examined by matrix-assisted laser desorption ionization-time of flight mass spectrometry, matrix-assisted laser desorption ionization post-source decay, and matrix-assisted laser desorption ionization tandem mass spectrometry. Where digests were performed in 50% H(2)(18)O, isotope profiles of peptide ions aided in the identification and characterization of disulfide-linked peptides. It was possible to produce two-chain peptides containing C1/C2, C3/C4, C5/C6, and C7/C12 linkages as revealed by comparison of the peptide masses before and after reduction and by post-source decay analysis. However, the remaining four half-cystines (C8, C9, C10, and C11) were located in a three-chain peptide of which one chain contained adjacent half-cystines (C9 and C10). The linkages of C8/C10 and C9/C11 were determined by tandem mass spectrometry of an in-source decay fragment ion containing C9, C10, and C11. This disulfide bond arrangement provides the basis for further refinement of flavivirus NS1 protein structural models.
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Affiliation(s)
- Tristan P Wallis
- Department of Microbiology and Parasitology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
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241
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Catteau A, Courageot MP, Desprès P. Flaviviruses and apoptosis regulation. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2004; 36:171-89. [PMID: 15171612 DOI: 10.1007/978-3-540-74264-7_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- A Catteau
- U.P. Flavivirus-Host Molecular Interactions, Virology Department, Pasteur Institute, 25 rue du Dr Roux, 75724 Paris cedex 15, France
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242
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Abstract
West Nile virus (WNV) is a mosquito-borne flavivirus that primarily infects birds but occasionally also infects humans and horses. In recent years, the frequency of WNV outbreaks in humans has increased, and these outbreaks have been associated with a higher incidence of severe disease. In 1999, the geographical distribution of WNV expanded to the Western hemisphere. WNV has a positive strand RNA genome of about 11 kb that encodes a single polyprotein. WNV replicates in the cytoplasm of infected cells. Although there are still many questions to be answered, a large body of data on the molecular biology of WNV and other flaviviruses has already been obtained. Aspects of virion structure, the viral replication cycle, viral protein function, genome structure, conserved viral elements, host factors, virus-host interactions, and vaccines are discussed in this review.
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Affiliation(s)
- Margo A Brinton
- Department of Biology, Georgia State University, Atlanta 30303, USA.
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243
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Abstract
Tick-borne encephalitis (TBE) is one of the most dangerous human infections occurring in Europe and many parts of Asia. The etiological agent Tick-borne encephalitis virus (TBEV), is a member of the virus genus Flavivirus, of the family Flaviviridae. TBEV is believed to cause at least 11,000 human cases of encephalitis in Russia and about 3000 cases in the rest of Europe annually. Related viruses within the same group, Louping ill virus (LIV), Langat virus (LGTV) and Powassan virus (POWV), also cause human encephalitis but rarely on an epidemic scale. Three other viruses within the same group, Omsk hemorrhagic fever virus (OHFV), Kyasanur Forest disease virus (KFDV) and Alkhurma virus (ALKV), are closely related to the TBEV complex viruses and tend to cause fatal hemorrhagic fevers rather than encephalitis. This review describes the clinical manifestations associated with TBEV infections, the main molecular-biological properties of these viruses, and the different factors that define the incidence and severity of disease. The role of ticks and their local hosts in the emergence of new virus variants with different pathogenic characteristics is also discussed. This review also contains a brief history of vaccination against TBE including trials with live attenuated vaccine and modern tendencies in developing of vaccine virus strains.
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MESH Headings
- Animals
- Bioterrorism/prevention & control
- Encephalitis Viruses, Tick-Borne/classification
- Encephalitis Viruses, Tick-Borne/genetics
- Encephalitis Viruses, Tick-Borne/immunology
- Encephalitis Viruses, Tick-Borne/pathogenicity
- Encephalitis, Tick-Borne/epidemiology
- Encephalitis, Tick-Borne/history
- Encephalitis, Tick-Borne/prevention & control
- Encephalitis, Tick-Borne/virology
- History, 20th Century
- Humans
- Vaccination/history
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/history
- Viral Vaccines/administration & dosage
- Viral Vaccines/history
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Affiliation(s)
- T S Gritsun
- CEH Institute of Virology and Environmental Microbiology, Mansfield Road, Oxford OX1 3SR, UK
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244
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Gritsun TS, Frolova TV, Zhankov AI, Armesto M, Turner SL, Frolova MP, Pogodina VV, Lashkevich VA, Gould EA. Characterization of a siberian virus isolated from a patient with progressive chronic tick-borne encephalitis. J Virol 2003; 77:25-36. [PMID: 12477807 PMCID: PMC140615 DOI: 10.1128/jvi.77.1.25-36.2003] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A strain of Tick-borne encephalitis virus designated Zausaev (Za) was isolated in Siberia from a patient who died of a progressive (2-year) form of tick-borne encephalitis 10 years after being bitten by a tick. The complete genomic sequence of this virus was determined, and an attempt was made to correlate the sequence with the biological characteristics of the virus. Phylogenetic analysis demonstrated that this virus belongs to the Siberian subtype of Tick-borne encephalitis virus. Comparison of Za virus with two related viruses, a Far Eastern isolate, Sofjin, and a Siberian isolate, Vasilchenko, revealed differences among the three viruses in pathogenicity for Syrian hamsters, cytopathogenicity for PS cells, plaque morphology, and the electrophoretic profiles of virus-specific nonstructural proteins. Comparative amino acid alignments revealed 10 individual amino acid substitutions in the Za virus polyprotein sequence that were different from those of other tick-borne flaviviruses. Notably, the dimeric form of the Za virus NS1 protein migrated in polyacrylamide gels as a heterogeneous group of molecules with a significantly higher electrophoretic mobility than those of the Sofjin and Vasilchenko viruses. Two amino acid substitutions, T(277)-->V and E(279)-->G, within the NS1 dimerization domain are probably responsible for the altered oligomerization of Za virus NS1. These studies suggest that the patient from whom Za virus was isolated died due to increased pathogenicity of the latent virus following spontaneous mutagenesis.
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Affiliation(s)
- T S Gritsun
- CEH Institute of Virology and Environmental Microbiology, Oxford OX1 3SR, United Kingdom
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245
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Alcon S, Talarmin A, Debruyne M, Falconar A, Deubel V, Flamand M. Enzyme-linked immunosorbent assay specific to Dengue virus type 1 nonstructural protein NS1 reveals circulation of the antigen in the blood during the acute phase of disease in patients experiencing primary or secondary infections. J Clin Microbiol 2002. [PMID: 11825945 DOI: 10.1128/jcm.40.02.376-3812002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
During flavivirus infection in vitro, nonstructural protein NS1 is released in a host-restricted fashion from infected mammalian cells but not vector-derived insect cells. In order to analyze the biological relevance of NS1 secretion in vivo, we developed a sensitive enzyme-linked immunosorbent assay (ELISA) to detect the protein in the sera of dengue virus-infected patients. The assay was based on serotype 1 NS1-specific mouse and rabbit polyclonal antibody preparations for antigen immunocapture and detection, respectively. With purified dengue virus type 1 NS1 as a protein standard, the sensitivity of our capture ELISA was less than 1 ng/ml. When a panel of patient sera was analyzed, the NS1 antigen was found circulating from the first day after the onset of fever up to day 9, once the clinical phase of the disease is over. The NS1 protein could be detected even when viral RNA was negative in reverse transcriptase-PCR or in the presence of immunoglobulin M antibodies. NS1 circulation levels varied among individuals during the course of the disease, ranging from several nanograms per milliliter to several micrograms per milliliter, and peaked in one case at 50 microg/ml of serum. Interestingly, NS1 concentrations did not differ significantly in serum specimens obtained from patients experiencing primary or secondary dengue virus infections. These findings indicate that NS1 protein detection may allow early diagnosis of infection. Furthermore, NS1 circulation in the bloodstream of patients during the clinical phase of the disease suggests a contribution of the nonstructural protein to dengue virus pathogenesis.
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Affiliation(s)
- Sophie Alcon
- Unité des Arbovirus et Virus des Fièvres Hémorragiques, Institut Pasteur, 75724 Paris Cedex 15, France
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246
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Alcon S, Talarmin A, Debruyne M, Falconar A, Deubel V, Flamand M. Enzyme-linked immunosorbent assay specific to Dengue virus type 1 nonstructural protein NS1 reveals circulation of the antigen in the blood during the acute phase of disease in patients experiencing primary or secondary infections. J Clin Microbiol 2002; 40:376-81. [PMID: 11825945 PMCID: PMC153354 DOI: 10.1128/jcm.40.02.376-381.2002] [Citation(s) in RCA: 412] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During flavivirus infection in vitro, nonstructural protein NS1 is released in a host-restricted fashion from infected mammalian cells but not vector-derived insect cells. In order to analyze the biological relevance of NS1 secretion in vivo, we developed a sensitive enzyme-linked immunosorbent assay (ELISA) to detect the protein in the sera of dengue virus-infected patients. The assay was based on serotype 1 NS1-specific mouse and rabbit polyclonal antibody preparations for antigen immunocapture and detection, respectively. With purified dengue virus type 1 NS1 as a protein standard, the sensitivity of our capture ELISA was less than 1 ng/ml. When a panel of patient sera was analyzed, the NS1 antigen was found circulating from the first day after the onset of fever up to day 9, once the clinical phase of the disease is over. The NS1 protein could be detected even when viral RNA was negative in reverse transcriptase-PCR or in the presence of immunoglobulin M antibodies. NS1 circulation levels varied among individuals during the course of the disease, ranging from several nanograms per milliliter to several micrograms per milliliter, and peaked in one case at 50 microg/ml of serum. Interestingly, NS1 concentrations did not differ significantly in serum specimens obtained from patients experiencing primary or secondary dengue virus infections. These findings indicate that NS1 protein detection may allow early diagnosis of infection. Furthermore, NS1 circulation in the bloodstream of patients during the clinical phase of the disease suggests a contribution of the nonstructural protein to dengue virus pathogenesis.
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Affiliation(s)
- Sophie Alcon
- Unité des Arbovirus et Virus des Fièvres Hémorragiques, Institut Pasteur, 75724 Paris Cedex 15, France
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247
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Enzyme-linked immunosorbent assay specific to Dengue virus type 1 nonstructural protein NS1 reveals circulation of the antigen in the blood during the acute phase of disease in patients experiencing primary or secondary infections. J Clin Microbiol 2002. [PMID: 11825945 DOI: 10.1128/jcm.40.2.376-381.2002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During flavivirus infection in vitro, nonstructural protein NS1 is released in a host-restricted fashion from infected mammalian cells but not vector-derived insect cells. In order to analyze the biological relevance of NS1 secretion in vivo, we developed a sensitive enzyme-linked immunosorbent assay (ELISA) to detect the protein in the sera of dengue virus-infected patients. The assay was based on serotype 1 NS1-specific mouse and rabbit polyclonal antibody preparations for antigen immunocapture and detection, respectively. With purified dengue virus type 1 NS1 as a protein standard, the sensitivity of our capture ELISA was less than 1 ng/ml. When a panel of patient sera was analyzed, the NS1 antigen was found circulating from the first day after the onset of fever up to day 9, once the clinical phase of the disease is over. The NS1 protein could be detected even when viral RNA was negative in reverse transcriptase-PCR or in the presence of immunoglobulin M antibodies. NS1 circulation levels varied among individuals during the course of the disease, ranging from several nanograms per milliliter to several micrograms per milliliter, and peaked in one case at 50 microg/ml of serum. Interestingly, NS1 concentrations did not differ significantly in serum specimens obtained from patients experiencing primary or secondary dengue virus infections. These findings indicate that NS1 protein detection may allow early diagnosis of infection. Furthermore, NS1 circulation in the bloodstream of patients during the clinical phase of the disease suggests a contribution of the nonstructural protein to dengue virus pathogenesis.
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248
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Blitvich BJ, Scanlon D, Shiell BJ, Mackenzie JS, Pham K, Hall RA. Determination of the intramolecular disulfide bond arrangement and biochemical identification of the glycosylation sites of the nonstructural protein NS1 of Murray Valley encephalitis virus. J Gen Virol 2001; 82:2251-2256. [PMID: 11514736 DOI: 10.1099/0022-1317-82-9-2251] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 12 cysteine residues in the flavivirus NS1 protein are strictly conserved, suggesting that they form disulfide bonds that are critical for folding the protein into a functional structure. In this study, we examined the intramolecular disulfide bond arrangement of NS1 of Murray Valley encephalitis virus and elucidated three of the six cysteine-pairing arrangements. Disulfide linkages were identified by separating tryptic-digested NS1 by reverse-phase high pressure liquid chromatography and analysing the resulting peptide peaks by protein sequencing, amino acid analysis and/or electrospray mass spectrometry. The pairing arrangements between the six amino-terminal cysteines were identified as follows: Cys(4)-Cys(15), Cys(55)-Cys(143) and Cys(179)-Cys(223). Although the pairing arrangements between the six carboxy-terminal cysteines were not determined, we were able to eliminate several cysteine-pairing combinations. Furthermore, we demonstrated that all three putative N-linked glycosylation sites of NS1 are utilized and that the Asn(207) glycosylation site contains a mannose-rich glycan.
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Affiliation(s)
- Bradley J Blitvich
- Department of Microbiology, The University of Western Australia, QE-II Medical Centre, Nedlands 6907, Australia1
| | - Denis Scanlon
- Protein Biochemistry, Australian Animal Health Laboratory, CSIRO Livestock Industries, Geelong 3220, Australia2
| | - Brian J Shiell
- Protein Biochemistry, Australian Animal Health Laboratory, CSIRO Livestock Industries, Geelong 3220, Australia2
| | - John S Mackenzie
- Department of Microbiology and Parasitology, The University of Queensland, St Lucia 4072, Australia3
- Department of Microbiology, The University of Western Australia, QE-II Medical Centre, Nedlands 6907, Australia1
| | - Kim Pham
- Department of Microbiology and Parasitology, The University of Queensland, St Lucia 4072, Australia3
| | - Roy A Hall
- Department of Microbiology and Parasitology, The University of Queensland, St Lucia 4072, Australia3
- Department of Microbiology, The University of Western Australia, QE-II Medical Centre, Nedlands 6907, Australia1
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249
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Hall RA, Khromykh AA, Mackenzie JM, Scherret JH, Khromykh TI, Mackenzie JS. Loss of dimerisation of the nonstructural protein NS1 of Kunjin virus delays viral replication and reduces virulence in mice, but still allows secretion of NS1. Virology 1999; 264:66-75. [PMID: 10544130 DOI: 10.1006/viro.1999.9956] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The flavivirus nonstructural protein NS1 has been implicated in viral RNA replication, although its precise role has not been identified. In its native state NS1 exists as a heat labile homodimer that is thought to be required for NS1 function and secretion. However, we have recently identified a cDNA clone of KUN virus (FLSD) that replicates efficiently in cell culture but produces and secretes NS1 in monomeric form. Sequence analysis of the NS1 gene in FLSD revealed a single amino acid substitution (proline(250) to leucine) when compared with the parental KUN virus. When site-directed mutagenesis was used to substitute leucine(250) with proline in FLSD to produce the clone 250pro, dimerisation was fully restored. Furthermore, time course experiments revealed that 250pro replicated in Vero cells significantly faster than FLSD and produced 100-fold more infectious virus early (12-24 h) in infection. This correlated with our observations that FLSD required approximately 10-fold more infectious virus than 250pro to produce disease in weanling mice after intraperitoneal inoculation. Taken together our results indicate that mutation from proline to leucine at residue 250 in KUN NS1 ablates dimer formation, slows virus replication, and reduces virulence in mice.
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Affiliation(s)
- R A Hall
- Department of Microbiology, University of Queensland, Brisbane, Queensland, 4072, Australia.
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