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Identification of B-Cell Epitopes on Capsid Protein Reveals Two Potential Neutralization Mechanisms in Red-Spotted Grouper Nervous Necrosis Virus. J Virol 2023; 97:e0174822. [PMID: 36633407 PMCID: PMC9888288 DOI: 10.1128/jvi.01748-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Nervous necrosis virus (NNV), a formidable pathogen in marine and freshwater fish, has inflicted enormous financial tolls on the aquaculture industry worldwide. Although capsid protein (CP) is the sole structural protein with pathogenicity and antigenicity, public information on immunodominant regions remains extremely scarce. Here, we employed neutralizing monoclonal antibodies (MAbs) specific for red-spotted grouper NNV (RGNNV) CNPgg2018 in combination with partially overlapping truncated proteins and peptides to identify two minimal B-cell epitope clusters on CP, 122GYVAGFL128 and 227SLYNDSL233. Site-directed mutational analysis confirmed residues Y123, G126, and L128 and residues L228, Y229, N230, D231, and L233 as the critical residues responsible for the direct interaction with ligand, respectively. According to homologous modeling and bioinformatic evaluation, 122GYVAGFL128 is harbored at the groove of the CP junction with strict conservation among all NNV isolates, while 227SLYNDSL233 is localized in proximity to the tip of a viral protrusion having relatively high evolutionary dynamics in different genotypes. Additionally, 227SLYNDSL233 was shown to be a receptor-binding site, since the corresponding polypeptide could moderately suppress RGNNV multiplication by impeding virion entry. In contrast, 122GYVAGFL128 seemed dedicated only to stabilizing viral native conformation and not to assisting initial virus attachment. Altogether, these findings contribute to a novel understanding of the antigenic distribution pattern of NNV and the molecular basis for neutralization, thus advancing the development of biomedical products, especially epitope-based vaccines, against NNV. IMPORTANCE NNV is a common etiological agent associated with neurological virosis in multiple aquatic organisms, causing significant hazards to the host. However, licensed drugs or vaccines to combat NNV infection are very limited to date. Toward the advancement of broad-spectrum prophylaxis and therapeutics against NNV, elucidating the diversity of immunodominant regions within it is undoubtedly essential. Here, we identified two independent B-cell epitopes on NNV CP, followed by the confirmation of critical amino acid residues participating in direct interaction. These two sites were distributed on the shell and protrusion domains of the virion, respectively, and mediated the neutralization exerted by MAbs via drastically distinct mechanisms. Our work promotes new insights into NNV antigenicity as well as neutralization and, more importantly, offers promising targets for the development of antiviral countermeasures.
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Yang JI, Kim KH. Display of Streptococcus iniae α-Enolase on the Surface of Virus-Like Particles (VLPs) of Nervous Necrosis Virus (NNV) Using SpyTag/SpyCatcher. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:1066-1072. [PMID: 36171522 DOI: 10.1007/s10126-022-10166-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
Virus-like particle (VLP)-based vaccines are promising candidates for overcoming the safety problems of live vaccines and weak immunogenicity of subunit vaccines. VLPs can be used as a platform for the development of combined vaccines by expressing foreign antigens, and foreign antigens can be displayed on the surface of VLPs by conjugation. In the present study, to use nervous necrosis virus (NNV) VLPs as a delivery tool for Streptococcus iniae α-enolase by displaying on the VLP's surface, the split-intein (SpyTag/SpyCatcher) conjugation system was used. NNV capsid protein fused to SpyTag (Capsid-SpyTag) and S. iniae α-enolase fused to SpyCatcher (α-enolase-SpyCatcher) were recombinantly produced, then mixed in various ratios. A ratio of Capsid-SpyTag to α-enolase-SpyCatcher of 1 to 1.5 showed the highest coupling efficiency corresponding to 83-92% of coupled capsid protein dimer and 32-52% of coupled capsid protein monomer. In TEM observation, VLP of Capsid-SpyTag had a regular shape and size of about 40 nm, while VLP fused with α-enolase-SpyCatcher showed an irregular shape and size of about 40-50 nm in diameter. In preliminary immunization experiments, olive flounder (Paralichthys olivaceus) and zebrafish (Danio rerio) immunized with VLP fused with α-enolase-SpyCatcher showed the lowest cumulative mortality against S. iniae infection.
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Affiliation(s)
- Jeong In Yang
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, South Korea
| | - Ki Hong Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, South Korea.
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Comprehensive Linear Epitope Prediction System for Host Specificity in Nodaviridae. Viruses 2022; 14:v14071357. [PMID: 35891339 PMCID: PMC9319239 DOI: 10.3390/v14071357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 02/01/2023] Open
Abstract
Background: Nodaviridae infection is one of the leading causes of death in commercial fish. Although many vaccines against this virus family have been developed, their efficacies are relatively low. Nodaviridae are categorized into three subfamilies: alphanodavirus (infects insects), betanodavirus (infects fish), and gammanodavirus (infects prawns). These three subfamilies possess host-specific characteristics that could be used to identify effective linear epitopes (LEs). Methodology: A multi-expert system using five existing LE prediction servers was established to obtain initial LE candidates. Based on the different clustered pathogen groups, both conserved and exclusive LEs among the Nodaviridae family could be identified. The advantages of undocumented cross infection among the different host species for the Nodaviridae family were applied to re-evaluate the impact of LE prediction. The surface structural characteristics of the identified conserved and unique LEs were confirmed through 3D structural analysis, and concepts of surface patches to analyze the spatial characteristics and physicochemical propensities of the predicted segments were proposed. In addition, an intelligent classifier based on the Immune Epitope Database (IEDB) dataset was utilized to review the predicted segments, and enzyme-linked immunosorbent assays (ELISAs) were performed to identify host-specific LEs. Principal findings: We predicted 29 LEs for Nodaviridae. The analysis of the surface patches showed common tendencies regarding shape, curvedness, and PH features for the predicted LEs. Among them, five predicted exclusive LEs for fish species were selected and synthesized, and the corresponding ELISAs for antigenic feature analysis were examined. Conclusion: Five identified LEs possessed antigenicity and host specificity for grouper fish. We demonstrate that the proposed method provides an effective approach for in silico LE prediction prior to vaccine development and is especially powerful for analyzing antigen sequences with exclusive features among clustered antigen groups.
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Chimeric virus-like particles (VLPs) designed from shrimp nodavirus (MrNV) capsid protein specifically target EGFR-positive human colorectal cancer cells. Sci Rep 2021; 11:16579. [PMID: 34400669 PMCID: PMC8367941 DOI: 10.1038/s41598-021-95891-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 07/30/2021] [Indexed: 12/24/2022] Open
Abstract
Recombinant MrNV capsid protein has been shown to effectively deliver plasmid DNA and dsRNA into Sf9 insect cells and shrimp tissues. To extend its application to cancer cell-targeting drug delivery, we created three different types of chimeric MrNV virus-like particles (VLPs) (R-MrNV, I-MrNV, and E-MrNV) that have specificity toward the epidermal growth factor receptor (EGFR), a cancer cell biomarker, by incorporating the EGFR-specific GE11 peptide at 3 different locations within the host cell recognition site of the capsid. All three chimeric MrNV-VLPs preserved the ability to form a mulberry-like VLP structure and to encapsulate EGFP DNA plasmid with an efficiency comparable to that previously reported for normal MrNV (N-MrNV). Compared to N-MrNV, the chimeric R-MrNV and E-MrNV carrying the exposed GE-11 peptide showed a significantly enhanced binding and internalization abilities that were specific towards EGFR expression in colorectal cancer cells (SW480). Specific targeting of chimeric MrNV to EGFR was proven by both EGFR silencing with siRNA vector and a competition with excess GE-11 peptide as well as the use of EGFR-negative colorectal cells (SW620) and breast cancer cells (MCF7). We demonstrated here that both chimeric R-MrNV and E-MrNV could be used to encapsulate cargo such as exogenous DNA and deliver it specifically to EGFR-positive cells. Our study presents the potential use of surface-modified VLPs of shrimp virus origin as nanocontainers for targeted cancer drug delivery.
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Sites responsible for infectivity and antigenicity on nervous necrosis virus (NNV) appear to be distinct. Sci Rep 2021; 11:3608. [PMID: 33574489 PMCID: PMC7878751 DOI: 10.1038/s41598-021-83078-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 01/28/2021] [Indexed: 11/18/2022] Open
Abstract
Nervous necrosis virus (NNV) is a pathogenic fish-virus belonging to the genus Betanodavirus (Nodaviridae). Surface protrusions on NNV particles play a crucial role in both antigenicity and infectivity. We exposed purified NNV particles to different physicochemical conditions to investigate the effects on antigenicity and infectivity, in order to reveal information regarding the conformational stability and spatial relationships of NNV neutralizing-antibody binding sites and cell receptor binding sites. Treatment with PBS at 37 °C, drastically reduced NNV antigenicity by 66–79% on day one, whereas its infectivity declined gradually from 107.6 to 105.8 TCID50/ml over 10 days. When NNV was treated with carbonate/bicarbonate buffers at different pHs, both antigenicity and infectivity of NNV declined due to higher pH. However, the rate of decline with respect to antigenicity was more moderate than for infectivity. NNV antigenicity declined 75–84% after treatment with 2.0 M urea, however, there was no reduction observed in infectivity. The antibodies used in antigenicity experiments have high NNV-neutralizing titers and recognize conformational epitopes on surface protrusions. The maintenance of NNV infectivity means that receptor binding sites are functionally preserved. Therefore, it seems highly likely that NNV neutralizing-antibody binding sites and receptor binding sites are independently located on surface protrusions.
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Jeong KH, Kim HJ, Kim HJ. Current status and future directions of fish vaccines employing virus-like particles. FISH & SHELLFISH IMMUNOLOGY 2020; 100:49-57. [PMID: 32130976 DOI: 10.1016/j.fsi.2020.02.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 02/25/2020] [Accepted: 02/27/2020] [Indexed: 05/15/2023]
Abstract
In most breeding schemes, fish are cultured in enclosed spaces, which greatly increases the risk of outbreaks where the onset of infectious diseases can cause massive mortality and enormous economic losses. Vaccination is the most effective and long-term measure for improving the basic make-up of a fish farm. As the relationship between antibody and antigen is similar to that between screw and nut, similarity in the shape or nature of the vaccine antigen to the original pathogen is important for achieving a satisfactory/good/excellent antibody response with a vaccine. Virus-like particles (VLPs) best fulfil this requirement as their tertiary structure mimics that of the native virus. For this reason, VLPs have been attracting attention as next-generation vaccines for humans and animals, and the effects of various types of VLP vaccines on humans and livestock have been examined. Recent studies of VLP-based fish vaccines indicate that these vaccines are promising, and raise hopes of extending their use in the near future. In this review, the structural properties and immunogenicity of VLP-based vaccines against fish viruses such as infectious pancreatic necrosis virus (IPNV), salmonid alphavirus (SAV), nervous necrosis virus (NNV) and iridovirus are introduced/summarized. The NNV VLP vaccine is the most-studied VLP-based vaccine against fish viruses. Therefore, the current status of NNV VLP research is highlighted in this review, which deals with the advantages of using VLPs as vaccines, and the expression systems for producing them. Moreover, the need for lyophilized VLPs and oral VLP delivery is discussed. Finally, future directions for the development of VLP vaccines in the fish vaccine field are considered.
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Affiliation(s)
- Ki-Ho Jeong
- Laboratory of Virology, College of Pharmacy, Chung-Ang University, 84 Heukseok-Ro, Dongjak-Gu, Seoul, 06974, South Korea
| | - Hyoung Jin Kim
- Laboratory of Virology, College of Pharmacy, Chung-Ang University, 84 Heukseok-Ro, Dongjak-Gu, Seoul, 06974, South Korea
| | - Hong-Jin Kim
- Laboratory of Virology, College of Pharmacy, Chung-Ang University, 84 Heukseok-Ro, Dongjak-Gu, Seoul, 06974, South Korea.
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Reproducibility of antigen-immobilized enzyme-linked immunosorbent assay (ELISA) and sandwich ELISA for quantitative detection of NNV particles. J Virol Methods 2019; 275:113754. [PMID: 31629807 DOI: 10.1016/j.jviromet.2019.113754] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/04/2019] [Accepted: 10/13/2019] [Indexed: 12/15/2022]
Abstract
Nervous necrosis virus (NNV) is a fish virus belonging to family Nodaviridae. In this study, we prepared partially aggregated and monometric NNV particles to determine reproducibility of two different enzyme-linked immunosorbent assays (ELISAs): antigen-immobilized ELISA and sandwich ELISA. Passing ratios of purified NNV particles through ultrafilters with molecular weight cut off (MWCO) of 105, 3 × 105 and 106 were 0%, 35.2% and 80.3%, respectively, suggesting that purified NNV particles were partially aggregated whereas those in filtrates with MWCO of 3 × 105 could be monometric. Both NNV particles were subjected to ELISAs. Reduction ratios of ELISA values by 2-fold dilution of antigens were 50% in sandwich ELISA regardless of aggregation state of NNV particles. In contrast, those in antigen-immobilized ELISA were 42% (partially aggregated NNV) to 43% (monometric NNV), which were lower than the theoretical value (50%). This could be due to changes in aggregation state of NNV particles during dry-immobilization. Sandwich ELISA has excellent reproducibility from five times of experiments, in comparison with antigen-immobilized ELISA. Furthermore, available range of regression lines (R2 > 0.99) in sandwich ELISA was wider than that in antigen-immobilized ELISA. These results revealed that sandwich ELISA had better quantitativeness, reproducibility and available range of ELISA values than antigen-immobilized ELISA.
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Altered conformational structures of nervous necrosis virus surface protrusions and free coat proteins after incubation at moderate-low temperatures. Sci Rep 2019; 9:8647. [PMID: 31201359 PMCID: PMC6573060 DOI: 10.1038/s41598-019-45094-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/29/2019] [Indexed: 12/18/2022] Open
Abstract
Nervous necrosis virus (NNV) is a pathogenic fish virus belonging to family Nodaviridae. The objective of this study was to analyze stabilities of NNV surface protrusion and free coat protein (CP) conformational structures by analyzing changes of NNV infectivity and antigenicity after incubation at moderate-low temperatures. When cultured NNV suspension was incubated at 45 °C, its infectivity declined gradually but its antigenicity maintained. In contrast, both infectivity and antigenicity of purified NNV declined after incubation at 45 °C. After heat-treatment, surface protrusions of NNV particles disappeared completely, although viral particle structures maintained. Therefore, the reduction in NNV infectivity appeared to specifically occur as a result of heat-denaturation of virus surface protrusions. The loss of NNV infectivity in the presence of fetal bovine serum (FBS) was delayed compared to virus heated in the absence of FBS, demonstrating that FBS could function as a stabilizer for conformational structures of NNV surface protrusions. Moreover, the stabilizing function of FBS changed depending on salt concentration. Continued maintenance of antigenicity for heated cultured NNV suspension containing free-CPs may suggest that conformational structures corresponding to protrusion-domain of free-CP are more heat-stable than those of surface protrusions on NNV particles.
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Gonzalez-Silvera D, Guardiola FA, Espinosa C, Chaves-Pozo E, Esteban MÁ, Cuesta A. Recombinant nodavirus vaccine produced in bacteria and administered without purification elicits humoral immunity and protects European sea bass against infection. FISH & SHELLFISH IMMUNOLOGY 2019; 88:458-463. [PMID: 30877059 DOI: 10.1016/j.fsi.2019.03.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/06/2019] [Accepted: 03/08/2019] [Indexed: 05/22/2023]
Abstract
Viral necrosis virus (NNV) or nodavirus causes fish viral encephalopathy and retinopathy worldwide. In some cases, mortalities in aquaculture industry can reach up to 100%, some species being especially sensitive as is the case of European sea bass (Dicentrarchus labrax), one of the main cultured species in the Mediterranean, with the consequent economical loses. Development of new vaccines against NNV is in the spotlight though few researches have focused in European sea bass. In this study we have generated a recombinant NNV (rNNV) vaccine produced in Escherichia coli expressing the capsid protein and administered it to European sea bass juveniles by two different routes (intraperitoneal and oral). The last being considered non-stressful and desired for fish farming of small fish, which in fact are the most affected by NNV. Oral vaccine was composed of feed pellets containing the recombinant whole bacteria, and injected vaccine was composed of recombinant bacteria previously lysed. Our results revealed production of specific anti-NNV IgM following the two vaccination procedures, levels that were further increased in orally-vaccinated group after challenge with NNV. Genes related to interferon (IFN), T-cell and immunoglobulin markers were scarcely regulated in head-kidney (HK), gut or brain. Vaccination by either route elicited a relative survival response of 100% after NNV challenge. To our knowledge, this is the first report of a recombinant vaccine followed by no purification steps which resulted in a complete protection in European sea bass when challenged with NNV.
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Affiliation(s)
- Daniel Gonzalez-Silvera
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", University of Murcia, 30100, Murcia, Spain
| | - Francisco A Guardiola
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", University of Murcia, 30100, Murcia, Spain; Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), University of Porto, Terminal de Cruzeiros Do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208, Porto, Portugal
| | - Cristóbal Espinosa
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", University of Murcia, 30100, Murcia, Spain
| | - Elena Chaves-Pozo
- Centro Oceanográfico de Murcia, Instituto Español de Oceanografía (IEO), Carretera de la Azohía s/n, Puerto de Mazarrón, 30860, Murcia, Spain
| | - M Ángeles Esteban
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", University of Murcia, 30100, Murcia, Spain
| | - Alberto Cuesta
- Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional "Campus Mare Nostrum", University of Murcia, 30100, Murcia, Spain.
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Yusuff S, Kurath G, Kim MS, Tesfaye TM, Li J, McKenney DG, Vakharia VN. The glycoprotein, non-virion protein, and polymerase of viral hemorrhagic septicemia virus are not determinants of host-specific virulence in rainbow trout. Virol J 2019; 16:31. [PMID: 30845963 PMCID: PMC6407216 DOI: 10.1186/s12985-019-1139-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 02/27/2019] [Indexed: 01/06/2023] Open
Abstract
Background Viral hemorrhagic septicemia virus (VHSV), a fish rhabdovirus belonging to the Novirhabdovirus genus, causes severe disease and mortality in many marine and freshwater fish species worldwide. VHSV isolates are classified into four genotypes and each group is endemic to specific geographic regions in the north Atlantic and Pacific Oceans. Most viruses in the European VHSV genotype Ia are highly virulent for rainbow trout (Oncorhynchus mykiss), whereas, VHSV genotype IVb viruses from the Great Lakes region in the United States, which caused high mortality in wild freshwater fish species, are avirulent for trout. This study describes molecular characterization and construction of an infectious clone of the virulent VHSV-Ia strain DK-3592B from Denmark, and application of the clone in reverse genetics to investigate the role of selected VHSV protein(s) in host-specific virulence in rainbow trout (referred to as trout-virulence). Methods Overlapping cDNA fragments of the DK-3592B genome were cloned after RT-PCR amplification, and their DNA sequenced by the di-deoxy chain termination method. A full-length cDNA copy (pVHSVdk) of the DK-3592B strain genome was constructed by assembling six overlapping cDNA fragments by using natural or artificially created unique restriction sites in the overlapping regions of the clones. Using an existing clone of the trout-avirulent VHSV-IVb strain MI03 (pVHSVmi), eight chimeric VHSV clones were constructed in which the coding region(s) of the glycoprotein (G), non-virion protein (NV), G and NV, or G, NV and L (polymerase) genes together, were exchanged between the two clones. Ten recombinant VHSVs (rVHSVs) were generated, including two parental rVHSVs, by transfecting fish cells with ten individual full-length plasmid constructs along with supporting plasmids using the established protocol. Recovered rVHSVs were characterized for viability and growth in vitro and used to challenge groups of juvenile rainbow trout by intraperitoneal injection. Results Complete sequence of the VHSV DK-3592B genome was determined from the cloned cDNA and deposited in GenBank under the accession no. KC778774. The trout-virulent DK-3592B genome (genotype Ia) is 11,159 nt in length and differs from the trout-avirulent MI03 genome (pVHSVmi) by 13% at the nucleotide level. When the rVHSVs were assessed for the trout-virulence phenotype in vivo, the parental rVHSVdk and rVHSVmi were virulent and avirulent, respectively, as expected. Four chimeric rVHSVdk viruses with the substitutions of the G, NV, G and NV, or G, NV and L genes from the avirulent pVHSVmi constructs were still highly virulent (100% mortality), while the reciprocal four chimeric rVHSVmi viruses with genes from pVHSVdk remained avirulent (0–10% mortality). Conclusions When chimeric rVHSVs, containing all the G, NV, and L gene substitutions, were tested in vivo, they did not exhibit any change in trout-virulence relative to the background clones. These results demonstrate that the G, NV and L genes of VHSV are not, by themselves or in combination, major determinants of host-specific virulence in trout.
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Affiliation(s)
- Shamila Yusuff
- Institute of Marine & Environmental Technology, University of Maryland Baltimore County, 701 E. Pratt Street, Baltimore, MD, 21202, USA.,GeneDX 207 Perry Parkway, Gaithersburg, MD, 20877, USA
| | - Gael Kurath
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA, 98115, USA
| | - Min Sun Kim
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA, 98115, USA.,Department of Integrative Bio-Industrial Engineering, Sejong University, Seoul, Republic of South Korea
| | - Tarin M Tesfaye
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA, 98115, USA
| | - Jie Li
- Institute of Marine & Environmental Technology, University of Maryland Baltimore County, 701 E. Pratt Street, Baltimore, MD, 21202, USA
| | - Douglas G McKenney
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA, 98115, USA
| | - Vikram N Vakharia
- Institute of Marine & Environmental Technology, University of Maryland Baltimore County, 701 E. Pratt Street, Baltimore, MD, 21202, USA.
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Low CF, Md Yusoff MR, Kuppusamy G, Ahmad Nadzri NF. Molecular biology of Macrobrachium rosenbergii nodavirus infection in giant freshwater prawn. JOURNAL OF FISH DISEASES 2018; 41:1771-1781. [PMID: 30270534 DOI: 10.1111/jfd.12895] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/24/2018] [Accepted: 08/25/2018] [Indexed: 06/08/2023]
Abstract
Macrobrachium rosenbergii nodavirus (MrNV) has been threatening the giant freshwater prawn aquaculture since 1997, causing white tail disease in the prawn species that leads to 100% lethality of the infected postlarvae. Comprehension of the viral infectivity and pathogenesis at molecular biology level has recently resolved the viral capsid protein and evidenced the significant difference in the viral structural protein compared to other nodaviruses that infect fish and insect. Cumulative researches have remarked the proposal to assert MrNV as a member of new genus, gammanodavirus to the Nodaviridae family. The significance of molecular biology in MrNV infection is being highlighted in this current review, revolving the viral life cycle from virus binding and entry into host, virus replication in host cell, to virus assembly and release. The current review also highlights the emerging aptamers technology that is also known as synthetic antibody, its application in disease diagnosis, and its prophylactic and therapeutic properties. The future perspective of synthetic virology technology in understanding viral pathogenesis, as well as its potential in viral vaccine development, is also discussed.
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Affiliation(s)
- Chen-Fei Low
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM, Bangi, Selangor, Malaysia
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Ho KL, Gabrielsen M, Beh PL, Kueh CL, Thong QX, Streetley J, Tan WS, Bhella D. Structure of the Macrobrachium rosenbergii nodavirus: A new genus within the Nodaviridae? PLoS Biol 2018; 16:e3000038. [PMID: 30346944 PMCID: PMC6211762 DOI: 10.1371/journal.pbio.3000038] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/01/2018] [Accepted: 10/05/2018] [Indexed: 11/19/2022] Open
Abstract
Macrobrachium rosenbergii nodavirus (MrNV) is a pathogen of freshwater prawns that poses a threat to food security and causes significant economic losses in the aquaculture industries of many developing nations. A detailed understanding of the MrNV virion structure will inform the development of strategies to control outbreaks. The MrNV capsid has also been engineered to display heterologous antigens, and thus knowledge of its atomic resolution structure will benefit efforts to develop tools based on this platform. Here, we present an atomic-resolution model of the MrNV capsid protein (CP), calculated by cryogenic electron microscopy (cryoEM) of MrNV virus-like particles (VLPs) produced in insect cells, and three-dimensional (3D) image reconstruction at 3.3 Å resolution. CryoEM of MrNV virions purified from infected freshwater prawn post-larvae yielded a 6.6 Å resolution structure, confirming the biological relevance of the VLP structure. Our data revealed that unlike other known nodavirus structures, which have been shown to assemble capsids having trimeric spikes, MrNV assembles a T = 3 capsid with dimeric spikes. We also found a number of surprising similarities between the MrNV capsid structure and that of the Tombusviridae: 1) an extensive network of N-terminal arms (NTAs) lines the capsid interior, forming long-range interactions to lace together asymmetric units; 2) the capsid shell is stabilised by 3 pairs of Ca2+ ions in each asymmetric unit; 3) the protruding spike domain exhibits a very similar fold to that seen in the spikes of the tombusviruses. These structural similarities raise questions concerning the taxonomic classification of MrNV.
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Affiliation(s)
- Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - Mads Gabrielsen
- CRUK Beatson Institute, Garscube Campus, Glasgow, Scotland United Kingdom
| | - Poay Ling Beh
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - Chare Li Kueh
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - Qiu Xian Thong
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - James Streetley
- MRC-University of Glasgow Centre for Virus Research, Garscube Campus, Glasgow, Scotland, United Kingdom
| | - Wen Siang Tan
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
- Institute of Bioscience, Universiti Putra Malaysia, UPM Serdang, Selangor Malaysia
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Garscube Campus, Glasgow, Scotland, United Kingdom
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Souto S, Olveira JG, Vázquez-Salgado L, Dopazo CP, Bandín I. Betanodavirus infection in primary neuron cultures from sole. Vet Res 2018; 49:86. [PMID: 30185222 PMCID: PMC6125867 DOI: 10.1186/s13567-018-0580-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/04/2018] [Indexed: 01/03/2023] Open
Abstract
Nervous necrosis virus (NNV), G. Betanodavirus, is the causative agent of viral encephalopathy and retinopathy, a disease that causes mass mortalities in a wide range of fish species. Betanodaviruses are neurotropic viruses and their replication in the susceptible fish species seems to be almost entirely restricted to nerve tissue. However, none of the cell lines used for NNV propagation has a nervous origin. In this study, first we established a protocol for the primary culture of neurons from Senegalese sole, which made it possible to further study virus-host cell interactions. Then, we compared the replication of three NNV strains with different genotypes (SJNNV, RGNNV and a RGNNV/SJNNV reassortant strain) in sole neuron primary cultures and E-11 cells. In addition, to study how two amino acid substitutions at the c-terminal of the capsid protein (positions 247 and 270) affect the binding to cell receptors, a recombinant strain was also tested. The results show that sole neural cells enabled replication of all the tested NNV strains. However, the recombinant strain shows a clearly delayed replication when compared with the wt strain. This delay was not observed in virus replicating in E-11 cells, suggesting a viral interaction with different cell receptors. The establishment of a sole primary neuronal culture protocol provides an important tool for research into betanodavirus infection in sole.
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Affiliation(s)
- Sandra Souto
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain.
| | - José G Olveira
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Lucía Vázquez-Salgado
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Carlos P Dopazo
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
| | - Isabel Bandín
- Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15706, Santiago de Compostela, Spain
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Huang R, Zhou Q, Shi Y, Zhang J, He J, Xie J. Protein A from orange-spotted grouper nervous necrosis virus triggers type I interferon production in fish cell. FISH & SHELLFISH IMMUNOLOGY 2018; 79:234-243. [PMID: 29733958 DOI: 10.1016/j.fsi.2018.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 04/29/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
Family Nodaviridae consists of two genera: Alphanodavirus and Betanodavirus, and the latter is classified into four genotypes, including red-spotted grouper nervous necrosis virus, tiger puffer nervous necrosis virus, striped jack nervous necrosis virus, and barfin flounder nervous necrosis virus. Type I interferons (IFNs) play a central role in the innate immune system and antiviral responses, and the interactions between IFN and NNV have been investigated in this study. We have found that the RNA-dependent RNA polymerase (RdRp) from orange-spotted nervous necrosis virus (OGNNV), named protein A, was capable of activating IFN promoter in fathead minnow (FHM) cells. Transient expression of protein A was found to induce IFN expression and secretion, endowing FHM cells with anti-tiger frog virus ability. Protein A from SJNNV can also induce IFN expression in FHM cells but that from Flock House virus (FHV), a well-studied representative species of genus Alphanodavirus, cannot. RdRp activity and mitochondrial localization were shown to be required for protein A to induce IFN expression by means of activating IRF3 but not NFκB. Furthermore, DsRNA synthesized in vitro transcription and poly I:C activated IFN promoter activity when transfected into FHM cells, and dsRNA were also detected in NNV-infected cells. We postulated that dsRNA, a PAMP, was produced by protein A, leading to activation of innate immune response. These results suggest that protein As from NNV are the agonists of innate immune response. This is the first work to demonstrate the interaction between NNV protein A and innate immune system, and may help to understand pathogenesis of NNV.
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Affiliation(s)
- Runqing Huang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qiong Zhou
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yan Shi
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jing Zhang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianguo He
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China; School of Marine Sciences, Sun Yat-sen University, Guangzhou, China.
| | - Junfeng Xie
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Provincial Key Laboratory of Improved Variety Reproduction in Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
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15
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Gye HJ, Oh MJ, Nishizawa T. Lack of nervous necrosis virus (NNV) neutralizing antibodies in convalescent sevenband grouper Hyporthodus septemfasciatus after NNV infection. Vaccine 2018; 36:1863-1870. [PMID: 29503111 DOI: 10.1016/j.vaccine.2018.02.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/08/2018] [Accepted: 02/15/2018] [Indexed: 10/17/2022]
Abstract
Viral nervous necrosis (VNN) is caused by nervous necrosis viruses (NNVs) belonging to genus Betanodavirus (Nodaviridae). It is one of the most serious diseases in aquaculture industry worldwide. In the present study, the kinetics of NNV-infectivity and NNV-specific antibodies in convalescent sevenband grouper Hyporthodus septemfasciatus after NNV infection was determined. When fish were infected with NNV at 17.5 °C, and reared for 84 days at natural seawater temperature (increasing rate: approximately 0.1 °C/day), NNV infectivity peaked on day 14 with 107.80 TCID50/g at the highest, and declined to below the detection limit. When convalescent fish were reared at 27 °C, and re-infected with NNV at 104.3 or 106.3 TCID50/fish, no mortality was observed although NNV multiplied up to 108.80 and 107.80 TCID50/g at the highest, respectively, suggesting NNV-specific immune response. It also revealed that convalescent fish were re-infected by NNV although NNV multiplication was strongly regulated. Interestingly, NNV-specific antibodies were detectable in 20% and ≥80% of convalescent fish before and after re-infection with NNV, respectively. However, no NNV-neutralizing activity was detected before and after re-infection in almost all of the convalescent fish. Therefore, NNV-neutralizing antibodies might not be necessary for the protection of convalescent fish against NNV re-infection after previous NNV infection.
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Affiliation(s)
- Hyun Jung Gye
- Department of Aqualife Medicine, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Myung-Joo Oh
- Department of Aqualife Medicine, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Toyohiko Nishizawa
- Department of Aqualife Medicine, Chonnam National University, Yeosu 59626, Republic of Korea.
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16
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Kim YC, Kwon WJ, Kim MS, Kim KI, Min JG, Jeong HD. High prevalence of betanodavirus barfin flounder nervous necrosis virus as well as red-spotted grouper nervous necrosis virus genotype in shellfish. JOURNAL OF FISH DISEASES 2018; 41:233-246. [PMID: 29027679 DOI: 10.1111/jfd.12702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/17/2017] [Accepted: 07/23/2017] [Indexed: 05/04/2023]
Abstract
Using two serially executed PCRs, the discriminative multiplex two-step RT-PCR (DMT-2 RT-PCR) following the detection seminested two-step RT-PCR (DSN-2 RT-PCR), we found a high frequency presence of BFNNV genotype as well as RGNNV in various domestic and imported shellfish. This was definitely different from the previous reports of outbreaks and asymptomatic infection only by the RGNNV genotype in cultured finfish in Korea. Cultivation of NNV entrapped in shellfish was performed successfully by a blind passage. Thus, in an attempt to elucidate the epidemiology of betanodavirus, experiments conducted on 969 shellfish samples concluded that (i) distribution of NNV genotype, especially BFNNV, in shellfish is clearly different from that found in finfish of the world; (ii) unlike RGNNV, which showed a high rate in summer, BFNNV showed no seasonal variation and this result suggests BFNNVs in the marine environment remain fairly constant throughout the year; and (iii) the entrapped virus in shellfish was alive and culturable in vitro. These results are the first report of high level prevalence of in vitro culturable NNV in shellfish, for both BFNNV and RGNNV, which may present a potential risk in transmitting nodaviruses to host species in a marine environment.
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Affiliation(s)
- Y C Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - W J Kwon
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - M S Kim
- Pathology Division, National Institute of Fisheries Science, Busan, Korea
| | - K I Kim
- Aquaculture Industry Division, East Sea Fisheries Research Institute, Gangwon-do, Korea
| | - J G Min
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - H D Jeong
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
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17
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Development of recombinant Yarrowia lipolytica producing virus-like particles of a fish nervous necrosis virus. J Microbiol 2017; 55:655-664. [PMID: 28752293 DOI: 10.1007/s12275-017-7218-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 07/04/2017] [Accepted: 07/04/2017] [Indexed: 11/27/2022]
Abstract
Nervous necrosis virus (NNV) causes viral encephalopathy and retinopathy, a devastating disease of many species of cultured marine fish worldwide. In this study, we used the dimorphic non-pathogenic yeast Yarrowia lipolytica as a host to express the capsid protein of red-spotted grouper nervous necrosis virus (RGNNV-CP) and evaluated its potential as a platform for vaccine production. An initial attempt was made to express the codon-optimized synthetic genes encoding intact and N-terminal truncated forms of RGNNV-CP under the strong constitutive TEF1 promoter using autonomously replicating sequence (ARS)-based vectors. The full-length recombinant capsid proteins expressed in Y. lipolytica were detected not only as monomers and but also as trimers, which is a basic unit for formation of NNV virus-like particles (VLPs). Oral immunization of mice with whole recombinant Y. lipolytica harboring the ARS-based plasmids was shown to efficiently induce the formation of IgG against RGNNV-CP. To increase the number of integrated copies of the RGNNV-CP expression cassette, a set of 26S ribosomal DNA-based multiple integrative vectors was constructed in combination with a series of defective Ylura3 with truncated promoters as selection markers, resulting in integrants harboring up to eight copies of the RGNNV-CP cassette. Sucrose gradient centrifugation and transmission electron microscopy of this high-copy integrant were carried out to confirm the expression of RGNNV-CPs as VLPs. This is the first report on efficient expression of viral capsid proteins as VLPs in Y. lipolytica, demonstrating high potential for the Y. lipolytica expression system as a platform for recombinant vaccine production based on VLPs.
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18
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Ho KL, Kueh CL, Beh PL, Tan WS, Bhella D. Cryo-Electron Microscopy Structure of the Macrobrachium rosenbergii Nodavirus Capsid at 7 Angstroms Resolution. Sci Rep 2017; 7:2083. [PMID: 28522842 PMCID: PMC5437026 DOI: 10.1038/s41598-017-02292-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/18/2017] [Indexed: 11/10/2022] Open
Abstract
White tail disease in the giant freshwater prawn Macrobrachium rosenbergii causes significant economic losses in shrimp farms and hatcheries and poses a threat to food-security in many developing countries. Outbreaks of Macrobrachium rosenbergii nodavirus (MrNV), the causative agent of white tail disease (WTD) are associated with up to 100% mortality rates. There are no interventions available to treat or prevent MrNV disease however. Here we show the structure of MrNV virus-like particles (VLPs) produced by recombinant expression of the capsid protein, using cryogenic electron microscopy. Our data show that MrNV VLPs package nucleic acids in a manner reminiscent of other known nodavirus structures. The structure of the capsid however shows striking differences from insect and fish infecting nodaviruses, which have been shown to assemble trimer-clustered T = 3 icosahedral virus particles. MrNV particles have pronounced dimeric blade-shaped spikes extending up to 6 nm from the outer surface of the capsid shell. Our structural analysis supports the assertion that MrNV may belong to a new genus of the Nodaviridae. Moreover, our study provides the first structural view of an important pathogen affecting aquaculture industries across the world.
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Affiliation(s)
- Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Chare Li Kueh
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, 43400 UPM, Serdang, Selangor, Malaysia
| | - Poay Ling Beh
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Wen Siang Tan
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, 43400 UPM, Serdang, Selangor, Malaysia
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK.
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19
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Huang R, Zhu G, Zhang J, Lai Y, Xu Y, He J, Xie J. Betanodavirus-like particles enter host cells via clathrin-mediated endocytosis in a cholesterol-, pH- and cytoskeleton-dependent manner. Vet Res 2017; 48:8. [PMID: 28179028 PMCID: PMC5299686 DOI: 10.1186/s13567-017-0412-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/15/2016] [Indexed: 11/10/2022] Open
Abstract
Betanodavirus, also referred to nervous necrosis virus (NNV), is the causative agent of the fatal disease, viral nervous necrosis and has brought significant economic losses in marine and freshwater cultured fish, especially larvae and juveniles. Here, we used an established invasion model with virus-like particle (VLP)-cells, mimicking orange-spotted grouper nervous necrosis virus (OGNNV), to investigate the crucial events of virus entry. VLP were observed in the perinuclear regions of Asian sea bass (SB) cells within 1.5 h after attachment. VLP uptake was strongly inhibited when cells were pretreated with biochemical inhibitors (chlorpromazine and dynasore) blocking clathrin-mediated endocytosis (CME) or transfected with siRNA against clathrin heavy and light chains. Inhibitors against key regulators of caveolae/raft-dependent endocytosis and macropinocytosis had no effect on VLP uptake. In contrast, disruption of cellular cholesterol by methyl-β-cyclodextrin or reduction of cholesterol fluidity by Cholera toxin B subunit significantly decreased VLP entry. Furthermore, VLP entry is dependent on low pH and cytoskeleton, demonstrated by inhibitor (chloroquine, ammonia chloride, cytochalasin D, wiskostatin, and nocodazole) perturbation. Therefore, OGNNV VLP enter SB cells via CME depending on dynamin-2, cholesterol and its fluidity, low pH, and cytoskeleton. In addition, ten more cell lines were screened for VLP entry and VLP can only enter NNV-sensitive cells, GB and SSN-1, via CME, indicating that CME is the common endocytosis pathway for VLP. These results may provide the data for NNV entry without the influence of the viral genome, an ideal model for exploring the behaviour of betanodavirus in cells, and valuable references to vaccine development.
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Affiliation(s)
- Runqing Huang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Guohua Zhu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Jing Zhang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yuxiong Lai
- Department of Nephrology, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou, China
| | - Yu Xu
- South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Jianguo He
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China.,School of Marine Sciences, Sun Yat-sen University, Guangzhou, China
| | - Junfeng Xie
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
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20
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Somrit M, Watthammawut A, Chotwiwatthanakun C, Ounjai P, Suntimanawong W, Weerachatyanukul W. C-terminal domain on the outer surface of the Macrobrachium rosenbergii nodavirus capsid is required for Sf9 cell binding and internalization. Virus Res 2017; 227:41-48. [DOI: 10.1016/j.virusres.2016.09.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 10/20/2022]
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21
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Souto S, Olveira JG, Dopazo CP, Bandín I. Reassortant betanodavirus infection in turbot (Scophthalmus maximus). JOURNAL OF FISH DISEASES 2016; 39:1347-1356. [PMID: 27135777 DOI: 10.1111/jfd.12466] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 01/09/2016] [Accepted: 01/10/2016] [Indexed: 06/05/2023]
Abstract
In this study, the susceptibility of turbot juveniles to two betanodavirus strains was assessed, a RGNNV/SJNNV reassortant (Ss160.03) and a SJNNV strain. The reassortant isolate exhibits a slightly modified SJNNV CP, with two amino acid substitutions in the C-terminal domain (positions 247 and 270). To analyse the role of these residues as virulence and host determinants in turbot, three recombinant strains (rSs160.03247 , rSs160.03270 , rSs160.03247+270 ) harbouring site-specific mutations in the CP sequence were also tested in experimental trials. Moderate mortalities (up to 50%) were recorded at 18 °C in the fish challenged with the Ss160.03 strain, whereas low mortalities (17%) were observed in the group challenged with the SJNNV strain. A slight decrease (around 10%) was observed in the mortalities caused by the mutants rSs160.03247 and rSs160.03270 , whilst the mutation of both positions reduced mortality by more than half of that observed in fish challenged with the wild strain. These results are confirmed by the replication in brain tissues, because whereas the wild strain was detected from 5 to 30 dpi and reached the highest viral load, the recombinant virus harbouring both mutations was not detected in the brain until 20 dpi and with a moderate viral load.
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Affiliation(s)
- S Souto
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
| | - J G Olveira
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - C P Dopazo
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - I Bandín
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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22
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Lin K, Zhu Z, Ge H, Zheng L, Huang Z, Wu S. Immunity to nervous necrosis virus infections of orange-spotted grouper (Epinephelus coioides) by vaccination with virus-like particles. FISH & SHELLFISH IMMUNOLOGY 2016; 56:136-143. [PMID: 27394969 DOI: 10.1016/j.fsi.2016.06.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/25/2016] [Accepted: 06/29/2016] [Indexed: 05/27/2023]
Abstract
Nervous necrosis virus (NNV) is a kind of the betanodaviruses, which can cause viral nervous necrosis (VNN) and massive mortality in larval and juvenile stages of orange-spotted grouper (Epinephelus coioides). Due to the lack of viral genomes, virus-like particles (VLPs) are considered as one of the most promising candidates in vaccine study to control this disease. In this study, a type of VLPs, which was engineered on the basis of orange-spotted grouper nervous necrosis virus (OGNNV), was produced from prokaryotes. They possessed the similar structure and size to the native NNV. In addition, synthetic oligodeoxynucleotide (ODN) containing CpG motif was added in vaccines, and the expression patterns of several genes were analyzed after injecting with VLP and VLP with adjuvant (VA) to assess the regulation effect of vaccine for inducing immune responses. RT-PCR assays showed that six related genes in healthy tissues were ubiquitously expressed in all nine tested tissues. The vaccine alone was able to enhance the expression of genes, including MHCIa, MyD88, TLR3, TLR9 and TLR22 after vaccination, indicating that the vaccine was able to induce immune response in grouper. In liver, spleen and kidney, the gene expressions of VA group were all significantly higher than that of VLP group at 72 h post-stimulation, showing that the fish of VA challenge group obtained the longer-lasting protective immunity and resistance to pathogen challenge than that of VLP group. The data indicated that the efficacy of vaccine could be further enhanced by CpG ODN after vaccination and provided the reference for the development of future viral vaccine in grouper.
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Affiliation(s)
- Kebing Lin
- Fisheries Research Institute of Fujian, Xiamen 361012, China; Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Xiamen 361012, China
| | - Zhihuang Zhu
- Fisheries Research Institute of Fujian, Xiamen 361012, China; Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Xiamen 361012, China
| | - Hui Ge
- Fisheries Research Institute of Fujian, Xiamen 361012, China; Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Xiamen 361012, China
| | - Leyun Zheng
- Fisheries Research Institute of Fujian, Xiamen 361012, China; Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Xiamen 361012, China
| | - Zhongchi Huang
- Fisheries Research Institute of Fujian, Xiamen 361012, China; Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Xiamen 361012, China.
| | - Shuiqing Wu
- Fisheries Research Institute of Fujian, Xiamen 361012, China; Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Xiamen 361012, China
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23
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Molecular Basis for Antigenic Diversity of Genus Betanodavirus. PLoS One 2016; 11:e0158814. [PMID: 27438093 PMCID: PMC4954670 DOI: 10.1371/journal.pone.0158814] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/22/2016] [Indexed: 11/20/2022] Open
Abstract
Betanodaviruses are the causative agents of viral nervous necrosis (VNN), a devastating disease for the Mediterranean mariculture. Four different betanodavirus species are recognized, Striped jack-, Redspotted grouper-, Tiger puffer-, and Barfin flounder nervous necrosis virus (SJNNV, RGNNV, TPNNV and BFNNV), but there is little knowledge on their antigenic properties. In order to describe the serological relationships among different betanodavirus genotypes, serum neutralization assays were performed using rabbit polyclonal antisera against eight fish nodaviruses that cover a wide species-, temporal-, spatial- and genetic range. The results indicate that the SJNNV and RGNNV are antigenically distinct, constituting serotypes A and C, respectively. The TPNNV and BFNNV, the latter representing cold-water betanodaviruses, are antigenically related and cluster within serotype B. The reassortant viruses RGNNV/SJNNV and SJNNV/RGNNV group within serotypes A and C, respectively, indicating that the coat protein encoded by RNA2 acts as major immunoreactivity determinant. Immunostaining of in vitro expressed wild type and chimeric capsid proteins between the RGNNV and the SJNNV species indicated that the C-terminal part of the capsid protein retains the immunoreactive portion. The amino acid (aa) residues determining RGNNV and SJNNV antigenic diversity were mapped to aa residues 217–256 and aa 257–341, respectively. Neutralization of reverse genetics derived chimeric viruses indicated that these areas determine the neutralizing epitopes. The data obtained are crucial for the development of targeted serological tests for the diagnosis of VNN, and informative for development of cross-protective vaccines against various betanodavirus genotypes.
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Jariyapong P. Nodavirus-based biological container for targeted delivery system. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2016; 43:355-60. [PMID: 24588230 DOI: 10.3109/21691401.2014.889702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Biological containers such as virus-like particles (VLPs) have gained increasing interest in the fields of gene therapy and vaccine development. Several virus-based materials have been studied, but the toxicity, biodistribution, and immunology of these systems still require extensive investigation. The specific goal of this review is to provide information about nodaviruses, which are causative infectious agents of insects and aquatic animals, but not humans. By understanding the structure and biophysical properties of such viruses, further chemical or genetic modification for novel nanocarriers could be developed. Therefore, their application for therapeutic purposes, particularly in humans, is of great interest.
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Xie J, Li K, Gao Y, Huang R, Lai Y, Shi Y, Yang S, Zhu G, Zhang Q, He J. Structural analysis and insertion study reveal the ideal sites for surface displaying foreign peptides on a betanodavirus-like particle. Vet Res 2016; 47:16. [PMID: 26754256 PMCID: PMC4710043 DOI: 10.1186/s13567-015-0294-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/21/2015] [Indexed: 01/09/2023] Open
Abstract
Betanodavirus infection causes fatal disease of viral nervous necrosis in many cultured marine and freshwater fish worldwide and the virus-like particles (VLP) are effective vaccines against betanodavirus. But vaccine and viral vector designs of betanodavirus VLP based on their structures remain lacking. Here, the three-dimensional structure of orange-spotted grouper nervous necrosis virus (OGNNV) VLP (RBS) at 3.9 Å reveals the organization of capsid proteins (CP). Based on the structural results, seven putative important sites were selected to genetically insert a 6× histidine (His)-tag for VLP formation screen, resulting in four His-tagged VLP (HV) at positions N-terminus, Ala220, Pro292 and C-terminus. The His-tags of N-terminal HV (NHV) were concealed inside virions while those of 220HV and C-terminal HV (CHV) were displayed at the outer surface. NHV, 220HV and CHV maintained the same cell entry ability as RBS in the Asian sea bass (SB) cell line, indicating that their similar surface structures can be recognized by the cellular entry receptor(s). For application of vaccine design, chromatography-purified CHV could provoke NNV-specific antibody responses as strong as those of RBS in a sea bass immunization assay. Furthermore, in carrying capacity assays, N-terminus and Ala220 can only carry short peptides and C-terminus can even accommodate large protein such as GFP to generate fluorescent VLP (CGV). For application of a viral vector, CGV could be real-time visualized to enter SB cells in invasion study. All the results confirmed that the C-terminus of CP is a suitable site to accommodate foreign peptides for vaccine design and viral vector development.
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Affiliation(s)
- Junfeng Xie
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Kunpeng Li
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Yuanzhu Gao
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Runqing Huang
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Yuxiong Lai
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 518080, China.
| | - Yan Shi
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Shaowei Yang
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Guohua Zhu
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Qinfen Zhang
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Jianguo He
- State Key Laboratory of Biocontrol, MOE Key Laboratory of Aquatic Product Safety, Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. .,School of Marine Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
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Chen NC, Yoshimura M, Guan HH, Wang TY, Misumi Y, Lin CC, Chuankhayan P, Nakagawa A, Chan SI, Tsukihara T, Chen TY, Chen CJ. Crystal Structures of a Piscine Betanodavirus: Mechanisms of Capsid Assembly and Viral Infection. PLoS Pathog 2015; 11:e1005203. [PMID: 26491970 PMCID: PMC4619592 DOI: 10.1371/journal.ppat.1005203] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 09/11/2015] [Indexed: 11/25/2022] Open
Abstract
Betanodaviruses cause massive mortality in marine fish species with viral nervous necrosis. The structure of a T = 3 Grouper nervous necrosis virus-like particle (GNNV-LP) is determined by the ab initio method with non-crystallographic symmetry averaging at 3.6 Å resolution. Each capsid protein (CP) shows three major domains: (i) the N-terminal arm, an inter-subunit extension at the inner surface; (ii) the shell domain (S-domain), a jelly-roll structure; and (iii) the protrusion domain (P-domain) formed by three-fold trimeric protrusions. In addition, we have determined structures of the T = 1 subviral particles (SVPs) of (i) the delta-P-domain mutant (residues 35−217) at 3.1 Å resolution; and (ii) the N-ARM deletion mutant (residues 35−338) at 7 Å resolution; and (iii) the structure of the individual P-domain (residues 214−338) at 1.2 Å resolution. The P-domain reveals a novel DxD motif asymmetrically coordinating two Ca2+ ions, and seems to play a prominent role in the calcium-mediated trimerization of the GNNV CPs during the initial capsid assembly process. The flexible N-ARM (N-terminal arginine-rich motif) appears to serve as a molecular switch for T = 1 or T = 3 assembly. Finally, we find that polyethylene glycol, which is incorporated into the P-domain during the crystallization process, enhances GNNV infection. The present structural studies together with the biological assays enhance our understanding of the role of the P-domain of GNNV in the capsid assembly and viral infection by this betanodavirus. Betanodaviruses belong to the family Nodaviridae and cause the mortality of numerous larval-stage fish species. Here we report protein crystal structures of a piscine betanodavirus, the Grouper nervous necrosis virus (GNNV), in four different forms. Highlights are two structural features that contribute to the viral molecular mechanisms of the T = 3 and T = 1 capsid assembly: a calcium-associated protrusion domain and a functional arginine-rich motif. These results also shed insights into the structural basis for evolutionary lineage of the family Nodaviridae.
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Affiliation(s)
- Nai-Chi Chen
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Masato Yoshimura
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Hong-Hsiang Guan
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Ting-Yu Wang
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Yuko Misumi
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Chien-Chih Lin
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Phimonphan Chuankhayan
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Atsushi Nakagawa
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Sunney I. Chan
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, United State of America
| | - Tomitake Tsukihara
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo, Japan
| | - Tzong-Yueh Chen
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
- * E-mail: (TYC); (CJC)
| | - Chun-Jung Chen
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
- Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
- Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
- * E-mail: (TYC); (CJC)
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A Review of Intra- and Extracellular Antigen Delivery Systems for Virus Vaccines of Finfish. J Immunol Res 2015; 2015:960859. [PMID: 26065009 PMCID: PMC4433699 DOI: 10.1155/2015/960859] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 01/04/2023] Open
Abstract
Vaccine efficacy in aquaculture has for a long time depended on evaluating relative percent survival and antibody responses after vaccination. However, current advances in vaccine immunology show that the route in which antigens are delivered into cells is deterministic of the type of adaptive immune response evoked by vaccination. Antigens delivered by the intracellular route induce MHC-I restricted CD8+ responses while antigens presented through the extracellular route activate MHC-II restricted CD4+ responses implying that the route of antigen delivery is a conduit to induction of B- or T-cell immune responses. In finfish, different antigen delivery systems have been explored that include live, DNA, inactivated whole virus, fusion protein, virus-like particles, and subunit vaccines although mechanisms linking these delivery systems to protective immunity have not been studied in detail. Hence, in this review we provide a synopsis of different strategies used to administer viral antigens via the intra- or extracellular compartments. Further, we highlight the differences in immune responses induced by antigens processed by the endogenous route compared to exogenously processed antigens. Overall, we anticipate that the synopsis put together in this review will shed insights into limitations and successes of the current vaccination strategies used in finfish vaccinology.
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He M, Teng CB. Divergence and codon usage bias of Betanodavirus, a neurotropic pathogen in fish. Mol Phylogenet Evol 2015; 83:137-42. [DOI: 10.1016/j.ympev.2014.11.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/25/2014] [Accepted: 11/30/2014] [Indexed: 11/17/2022]
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Souto S, Mérour E, Biacchesi S, Brémont M, Olveira JG, Bandín I. In vitro and in vivo characterization of molecular determinants of virulence in reassortant betanodavirus. J Gen Virol 2015; 96:1287-1296. [PMID: 25626678 DOI: 10.1099/vir.0.000064] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/19/2015] [Indexed: 01/25/2023] Open
Abstract
We previously reported that betanodavirus reassortant strains [redspotted grouper nervous necrosis virus/striped jack nervous necrosis virus (SJNNV)] isolated from Senegalese sole (Solea senegalensis) exhibited a modified SJNNV capsid amino acid sequence, with changes at aa 247 and 270. In the current study, we investigated the possible role of both residues as putative virulence determinants. Three recombinant viruses harbouring site-specific mutations in the capsid protein sequence, rSs160.03247 (S247A), rSs160.03270 (S270N) and rSs160.03247+270 (S247A/S270N), were generated using a reverse genetics system. These recombinant viruses were studied in cell culture and in vivo in the natural fish host. The three mutant viruses were shown to be infectious and able to replicate in E-11 cells, reaching final titres similar to the WT virus, although with a somewhat slower kinetics of replication. When the effect of the amino acid substitutions on virus pathogenicity was evaluated in Senegalese sole, typical clinical signs of betanodavirus infection were observed in all groups. However, fish mortality induced by all three mutant viruses was clearly affected. Roughly 40 % of the fish survived in these three groups in contrast with the WT virus which killed 100 % of the fish. These data demonstrated that aa 247 and 270 play a major role in betanodavirus virulence although when both mutated aa 247 and 270 are present, corresponding recombinant virus was not further attenuated.
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Affiliation(s)
- Sandra Souto
- Instituto de Acuicultura, Universidad de Santiago de Compostela, A Coruña, Spain
| | - Emilie Mérour
- Unité de Virologie et Immunologie Moléculaires, INRA, Jouy en Josas, France
| | - Stéphane Biacchesi
- Unité de Virologie et Immunologie Moléculaires, INRA, Jouy en Josas, France
| | - Michel Brémont
- Unité de Virologie et Immunologie Moléculaires, INRA, Jouy en Josas, France
| | - José G Olveira
- Instituto de Acuicultura, Universidad de Santiago de Compostela, A Coruña, Spain
| | - Isabel Bandín
- Instituto de Acuicultura, Universidad de Santiago de Compostela, A Coruña, Spain
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A unique nodavirus with novel features: mosinovirus expresses two subgenomic RNAs, a capsid gene of unknown origin, and a suppressor of the antiviral RNA interference pathway. J Virol 2014; 88:13447-59. [PMID: 25210176 DOI: 10.1128/jvi.02144-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED Insects are a reservoir for many known and novel viruses. We discovered an unknown virus, tentatively named mosinovirus (MoNV), in mosquitoes from a tropical rainforest region in Côte d'Ivoire. The MoNV genome consists of two segments of positive-sense RNA of 2,972 nucleotides (nt) (RNA 1) and 1,801 nt (RNA 2). Its putative RNA-dependent RNA polymerase shares 43% amino acid identity with its closest relative, that of the Pariacoto virus (family Nodaviridae). Unexpectedly, for the putative capsid protein, maximal pairwise identity of 16% to Lake Sinai virus 2, an unclassified virus with a nonsegmented RNA genome, was found. Moreover, MoNV virions are nonenveloped and about 50 nm in diameter, larger than any of the known nodaviruses. Mature MoNV virions contain capsid proteins of ∼ 56 kDa, which do not seem to be cleaved from a longer precursor. Northern blot analyses revealed that MoNV expresses two subgenomic RNAs of 580 nt (RNA 3) and 292 nt (RNA 4). RNA 4 encodes a viral suppressor of RNA interference (RNAi) that shares its mechanism with the B2 RNAi suppressor protein of other nodaviruses despite lacking recognizable similarity to these proteins. MoNV B2 binds long double-stranded RNA (dsRNA) and, accordingly, inhibits Dicer-2-mediated processing of dsRNA into small interfering RNAs (siRNAs). Phylogenetic analyses indicate that MoNV is a novel member of the family Nodaviridae that acquired its capsid gene via reassortment from an unknown, distantly related virus beyond the family level. IMPORTANCE The identification of novel viruses provides important information about virus evolution and diversity. Here, we describe an unknown unique nodavirus in mosquitoes, named mosinovirus (MoNV). MoNV was classified as a nodavirus based on its genome organization and on phylogenetic analyses of the RNA-dependent RNA polymerase. Notably, its capsid gene was acquired from an unknown virus with a distant relationship to nodaviruses. Another remarkable feature of MoNV is that, unlike other nodaviruses, it expresses two subgenomic RNAs (sgRNAs). One of the sgRNAs expresses a protein that counteracts antiviral defense of its mosquito host, whereas the function of the other sgRNA remains unknown. Our results show that complete genome segments can be exchanged beyond the species level and suggest that insects harbor a large repertoire of exceptional viruses.
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Abstract
Orsay, the first virus discovered to naturally infect Caenorhabditis elegans or any nematode, has a bipartite, positive-sense RNA genome. Sequence analyses show that Orsay is related to nodaviruses, but molecular characterizations of Orsay reveal several unique features, such as the expression of a capsid-δ fusion protein and the use of an ATG-independent mechanism for translation initiation. Here we report the crystal structure of an Orsay virus-like particle assembled from recombinant capsid protein (CP). Orsay capsid has a T = 3 icosahedral symmetry with 60 trimeric surface spikes. Each CP can be divided into three regions: an N-terminal arm that forms an extended protein interaction network at the capsid interior, an S domain with a jelly-roll, β-barrel fold forming the continuous capsid, and a P domain that forms surface spike projections. The structure of the Orsay S domain is best aligned to T = 3 plant RNA viruses but exhibits substantial differences compared with the insect-infecting alphanodaviruses, which also lack the P domain in their CPs. The Orsay P domain is remotely related to the P1 domain in calicivirus and hepatitis E virus, suggesting a possible evolutionary relationship. Removing the N-terminal arm produced a slightly expanded capsid with fewer nucleic acids packaged, suggesting that the arm is important for capsid stability and genome packaging. Because C. elegans-Orsay serves as a highly tractable model for studying viral pathogenesis, our results should provide a valuable structural framework for further studies of Orsay replication and infection.
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Luo YC, Wang CH, Wu YM, Liu W, Lu MW, Lin CS. Crystallization and X-ray diffraction of virus-like particles from a piscine betanodavirus. Acta Crystallogr F Struct Biol Commun 2014; 70:1080-6. [PMID: 25084387 PMCID: PMC4118809 DOI: 10.1107/s2053230x14013703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/11/2014] [Indexed: 11/10/2022] Open
Abstract
Dragon grouper nervous necrosis virus (DGNNV), a member of the genus Betanodavirus, causes high mortality of larvae and juveniles of the grouper fish Epinephelus lanceolatus. Currently, there is no reported crystal structure of a fish nodavirus. The DGNNV virion capsid is derived from a single open reading frame that encodes a 338-amino-acid protein of approximately 37 kDa. The capsid protein of DGNNV was expressed to form virus-like particles (VLPs) in Escherichia coli. The VLP shape is T = 3 quasi-symmetric with a diameter of ∼38 nm in cryo-electron microscopy images and is highly similar to the native virion. In this report, crystals of DGNNV VLPs were grown to a size of 0.27 mm within two weeks by the hanging-drop vapour-diffusion method at 283 K and diffracted X-rays to ∼7.5 Å resolution. In-house X-ray diffraction data of the DGNNV VLP crystals showed that the crystals belonged to space group R32, with unit-cell parameters a = b = 353.00, c = 800.40 Å, α = β = 90, γ = 120°. 23 268 unique reflections were acquired with an overall Rmerge of 18.2% and a completeness of 93.2%. Self-rotation function maps confirmed the fivefold, threefold and twofold symmetries of the icosahedron of DGNNV VLPs.
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Affiliation(s)
- Yu-Chun Luo
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Chun-Hsiung Wang
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Yi-Min Wu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Wangta Liu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Ming-Wei Lu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Chan-Shing Lin
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
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Tan M, Jiang X. Subviral particle as vaccine and vaccine platform. Curr Opin Virol 2014; 6:24-33. [PMID: 24662314 PMCID: PMC4072748 DOI: 10.1016/j.coviro.2014.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 02/28/2014] [Accepted: 02/28/2014] [Indexed: 01/01/2023]
Abstract
Recombinant subvirual particles retain similar antigenic features of their authentic viral capsids and thus have been applied as nonreplicating subunit vaccines against viral infection and illness. Additionally, the self-assembled, polyvalent subviral particles are excellent platforms to display foreign antigens for immune enhancement for vaccine development. These subviral particle-based vaccines are noninfectious and thus safer than the conventional live attenuated and inactivated vaccines. While several VLP vaccines are available in the markets, numerous others, including dual vaccines against more than one pathogen, are under clinical or preclinical development. This article provides an update of these efforts.
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Affiliation(s)
- Ming Tan
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
| | - Xi Jiang
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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Jariyapong P, Chotwiwatthanakun C, Somrit M, Jitrapakdee S, Xing L, Cheng HR, Weerachatyanukul W. Encapsulation and delivery of plasmid DNA by virus-like nanoparticles engineered from Macrobrachium rosenbergii nodavirus. Virus Res 2013; 179:140-6. [PMID: 24184445 DOI: 10.1016/j.virusres.2013.10.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/29/2013] [Accepted: 10/24/2013] [Indexed: 12/29/2022]
Abstract
Virus-like particles (VLPs) are potential candidates in developing biological containers for packaging therapeutic or biologically active agents. Here, we expressed Macrobrachium rosenbergii nodavirus (MrNv) capsid protein (encoding amino acids M1-N371 with 6 histidine residuals) in an Escherichia coli BL21(DE3). These easily purified capsid protein self-assembled into VLPs, and disassembly/reassembly could be controlled in a calcium-dependent manner. Physically, MrNv VLPs resisted to digestive enzymes, a property that should be advantageous for protection of active compounds against harsh conditions. We also proved that MrNv VLPs were capable of encapsulating plasmid DNA in the range of 0.035-0.042 mol ratio (DNA/protein) or 2-3 plasmids/VLP (assuming that MrNV VLPs is T=1, i made up of 60 capsid monomers). These VLPs interacted with cultured insect cells and delivered loaded plasmid DNA into the cells as shown by green fluorescent protein (GFP) reporter. With many advantageous properties including self-encapsulation, MrNv VLPs are good candidates for delivery of therapeutic agents.
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Affiliation(s)
- Pitchanee Jariyapong
- Department of Anatomy, Faculty of Science, Mahidol University, Rama 6 Road, Phyathai, Bangkok 10400, Thailand; School of Medicine, Walailak University, Thasala District, Nakhonsrithammarat, Thailand
| | | | - Monsicha Somrit
- Department of Anatomy, Faculty of Science, Mahidol University, Rama 6 Road, Phyathai, Bangkok 10400, Thailand
| | - Sarawut Jitrapakdee
- Department of Biochemistry, Faculty of Science, Mahidol University, Rama 6 Road, Phyathai, Bangkok 10400, Thailand
| | - Li Xing
- Department of Molecular and Cell Biology, University of California, Davis, CA 95616, United States
| | - Holland R Cheng
- Department of Molecular and Cell Biology, University of California, Davis, CA 95616, United States
| | - Wattana Weerachatyanukul
- Department of Anatomy, Faculty of Science, Mahidol University, Rama 6 Road, Phyathai, Bangkok 10400, Thailand.
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Chromatographically-purified capsid proteins of red-spotted grouper nervous necrosis virus expressed in Saccharomyces cerevisiae form virus-like particles. Protein Expr Purif 2013; 89:162-8. [DOI: 10.1016/j.pep.2013.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/08/2013] [Accepted: 03/18/2013] [Indexed: 11/19/2022]
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36
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Bravo J, Real F, Padilla D, Olveira JG, Grasso V, Román L, Acosta F. Effect of lipopolysaccharides from Vibrio alginolyticus on the Mx gene expression and virus recovery from gilthead sea bream (Sparus aurata L.) experimentally infected with Nodavirus. FISH & SHELLFISH IMMUNOLOGY 2013; 34:383-386. [PMID: 23092730 DOI: 10.1016/j.fsi.2012.10.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 09/26/2012] [Accepted: 10/07/2012] [Indexed: 06/01/2023]
Abstract
Infections with nodavirus affect a wild and farmed fish species throughout the world, mostly from the marine environment. The aim of this work was to determine the immune status of gilthead sea bream that comes as a result of a Nodavirus infection, induced by activation of the interferon response pathway by lipopolysaccharides from Vibrio alginolyticus and the expression of interferoninduced Mx protein in liver samples. The enhancement of Mx protein gene expression was detected in liver samples of experimentally nodavirus infected fish and, furthermore, the immunostimulant LPS of V. alginolyticus decreased almost three times the virus titration with respect to no-immunized or infected with nodavirus group of fish.
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Affiliation(s)
- J Bravo
- Instituto Universitario de Sanidad Animal, Universidad de Las Palmas de Gran Canaria, Arucas, Spain
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Miller JL, Woodward J, Chen S, Jaffer M, Weber B, Nagasaki K, Tomaru Y, Wepf R, Roseman A, Varsani A, Sewell T. Three-dimensional reconstruction of Heterocapsa circularisquama RNA virus by electron cryo-microscopy. J Gen Virol 2011; 92:1960-1970. [PMID: 21562120 DOI: 10.1099/vir.0.031211-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Heterocapsa circularisquama RNA virus is a non-enveloped icosahedral ssRNA virus infectious to the harmful bloom-forming dinoflagellate, H. circularisquama, and which is assumed to be the major natural agent controlling the host population. The viral capsid is constructed from a single gene product. Electron cryo-microscopy revealed that the virus has a diameter of 34 nm and T = 3 symmetry. The 180 quasi-equivalent monomers have an unusual arrangement in that each monomer contributes to a 'bump' on the surface of the protein. Though the capsid protein probably has the classic 'jelly roll' β-sandwich fold, this is a new packing arrangement and is distantly related to the other positive-sense ssRNA virus capsid proteins. The handedness of the structure has been determined by a novel method involving high resolution scanning electron microscopy of the negatively stained viruses and secondary electron detection.
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Affiliation(s)
- Jennifer L Miller
- Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Jeremy Woodward
- Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Shaoxia Chen
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK
| | - Mohammed Jaffer
- Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Brandon Weber
- Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Keizo Nagasaki
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hiroshima 739-0452, Japan
| | - Yuji Tomaru
- National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hiroshima 739-0452, Japan
| | - Roger Wepf
- Electron Microscopy ETH Zurich (EMEZ), 8093 Zurich, Switzerland
| | - Alan Roseman
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Arvind Varsani
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.,Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.,Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
| | - Trevor Sewell
- Electron Microscope Unit, Division of Medical Biochemistry, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
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38
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Biacchesi S. The reverse genetics applied to fish RNA viruses. Vet Res 2011; 42:12. [PMID: 21314978 PMCID: PMC3037892 DOI: 10.1186/1297-9716-42-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 11/18/2010] [Indexed: 02/05/2023] Open
Abstract
Aquaculture has expanded rapidly to become a major economic and food-producing sector worldwide these last 30 years. In parallel, viral diseases have emerged and rapidly spread from farm to farm causing enormous economic losses. The most problematic viruses encountered in the field are mainly, but not exclusively, RNA viruses belonging to the Novirhabdovirus, Aquabirnavirus, Alphavirus and Betanodavirus genera. The recent establishment of reverse genetics systems to recover infectious fish RNA viruses entirely from cDNA has made possible to genetically manipulate the viral genome. These systems have provided powerful tools to study all aspects of the virus biology and virus-host interactions but also gave the opportunity to use these viruses as live vaccines or as gene vectors. This review provides an overview on the recent breakthroughs achieved by using these reverse genetics systems in terms of viral protein function, virulence and host-specificity factor, vaccine development and vector design.
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Affiliation(s)
- Stéphane Biacchesi
- Unité de Virologie et Immunologie Moléculaires, INRA, CRJ, 78352 Jouy-en-Josas, France.
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39
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Affiliation(s)
- Adam Zlotnick
- Department of Biology, Indiana University Bloomington IN 47405 USA
| | - Bentley A. Fane
- Division of Plant Pathology and Microbiology, Department of Plant Sciences and The BIO5 Institute, University of Arizona Tucson AZ 85721 USA
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40
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Roles of cysteines Cys115 and Cys201 in the assembly and thermostability of grouper betanodavirus particles. Virus Genes 2010; 41:73-80. [PMID: 20446029 PMCID: PMC2886913 DOI: 10.1007/s11262-010-0488-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 04/19/2010] [Indexed: 11/06/2022]
Abstract
The virus-like particle (VLP) assembled from capsid subunits of the dragon grouper nervous necrosis virus (DGNNV) is very similar to its native T = 3 virion. In order to investigate the effects of four cysteine residues in the capsid polypeptide on the assembly/dissociation pathways of DGNNV virions, we recombinantly cloned mutant VLPs by mutating each cysteine to destroy the specific disulfide linkage as compared with thiol reduction to destroy all S–S bonds. The mutant VLPs of C187A and C331A mutations were similar to wild-type VLPs (WT-VLPs); hence, the effects of Cys187 and Cys331 on the particle formation and thermostability were presumably negligible. Electron microscopy showed that either C115A or C201A mutation disrupted de novo VLP formation significantly. As shown in micrographs and thermal decay curves, β-mercaptoethanol-treated WT-VLPs remained intact, merely resulting in lower tolerance to thermal disruption than native WT-VLPs. This thiol reduction broke disulfide linkages inside the pre-fabricated VLPs, but it did not disrupt the appearance of icosahedrons. Small dissociated capsomers from EGTA-treated VLPs were able to reassemble back to icosahedrons in the presence of calcium ions, but additional treatment with β-mercaptoethanol during EGTA dissociation resulted in inability of the capsomers to reassemble into the icosahedral form. These results indicated that Cys115 and Cys201 were essential for capsid formation of DGNNV icosahedron structure in de novo assembly and reassembly pathways, as well as for the thermal stability of pre-fabricated particles.
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41
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Olveira JG, Souto S, Dopazo CP, Thiéry R, Barja JL, Bandín I. Comparative analysis of both genomic segments of betanodaviruses isolated from epizootic outbreaks in farmed fish species provides evidence for genetic reassortment. J Gen Virol 2009; 90:2940-2951. [PMID: 19710256 DOI: 10.1099/vir.0.013912-0] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Sequencing of the full coding region of both genomic segments of seven betanodavirus strains isolated from different farmed species in Spain and Portugal revealed that six were reassortants, exhibiting a red-spotted grouper nervous necrosis virus (RGNNV)-type RNA1 and a striped jack nervous necrosis virus (SJNNV)-type RNA2. Analysis of sequences of reassortant strains at both the genomic and protein levels revealed the existence of differences compared with type strains of both genotypes. These differences were greater in the polymerase sequence, which is remarkable because viral structural proteins generally diverge more rapidly than non-structural proteins. Changes in two amino acids observed in the SJNNV capsid protein might be involved in the colonization of new host species by these reassortant strains. In addition, a more extensive phylogenetic analysis, including partial sequences of both RNA segments of 16 other Iberian nodaviruses, confirmed the existence of reassortment between RGNNV and SJNNV.
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Affiliation(s)
- J G Olveira
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Spain
| | - S Souto
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Spain
| | - C P Dopazo
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Spain
| | - R Thiéry
- French Food Safety Agency, BP111, F-06902 Sophia Antipolis, France
| | - J L Barja
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Spain
| | - I Bandín
- Unidad de Ictiopatología-Patología Viral, Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, Spain
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42
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Ambrose RL, Lander GC, Maaty WS, Bothner B, Johnson JE, Johnson KN. Drosophila A virus is an unusual RNA virus with a T=3 icosahedral core and permuted RNA-dependent RNA polymerase. J Gen Virol 2009; 90:2191-200. [PMID: 19474243 DOI: 10.1099/vir.0.012104-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The vinegar fly, Drosophila melanogaster, is a popular model for the study of invertebrate antiviral immune responses. Several picorna-like viruses are commonly found in both wild and laboratory populations of D. melanogaster. The best-studied and most pathogenic of these is the dicistrovirus Drosophila C virus. Among the uncharacterized small RNA viruses of D. melanogaster, Drosophila A virus (DAV) is the least pathogenic. Historically, DAV has been labelled as a picorna-like virus based on its particle size and the content of its RNA genome. Here, we describe the characterization of both the genome and the virion structure of DAV. Unexpectedly, the DAV genome was shown to encode a circular permutation in the palm-domain motifs of the RNA-dependent RNA polymerase. This arrangement has only been described previously for a subset of viruses from the double-stranded RNA virus family Birnaviridae and the T=4 single-stranded RNA virus family Tetraviridae. The 8 A (0.8 nm) DAV virion structure computed from cryo-electron microscopy and image reconstruction indicates that the virus structural protein forms two discrete domains within the capsid. The inner domain is formed from a clear T=3 lattice with similarity to the beta-sandwich domain of tomato bushy stunt virus, whilst the outer domain is not ordered icosahedrally, but forms a cage-like structure that surrounds the core domain. Taken together, this indicates that DAV is highly divergent from previously described viruses.
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Affiliation(s)
- Rebecca L Ambrose
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
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43
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Wu YM, Hsu CH, Wang CH, Liu W, Chang WH, Lin CS. Role of the DxxDxD motif in the assembly and stability of betanodavirus particles. Arch Virol 2008; 153:1633-42. [PMID: 18626568 DOI: 10.1007/s00705-008-0150-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2007] [Accepted: 05/26/2008] [Indexed: 11/29/2022]
Abstract
Piscine betanodavirus possesses a bipartite genome of single-stranded (+)RNAs. RNA2 cDNA of dragon grouper nervous necrosis virus (DGNNV) has been expressed previously to form virus-like particles (VLPs), which are highly similar to the native virion. Experiments with calcium-chelating or reducing/oxidizing reagents showed that the DGNNV VLPs required only calcium for particle assembly. With the recombinant VLPs, site-directed mutagenesis can be employed to investigate the roles of calcium-binding ligands in particle formation. The results of mutational analysis of DxxDxD, which is putatively involved in the coordination of calcium ions, showed that the D133N mutation significantly disrupted the assembly of VLPs, while D130N and D135N mutants produced heterogeneous VLPs with broken shapes. The thermal stability of the VLP-forming fractions demonstrated that VLPs of the D135N mutant were stable at a temperature of 85 degrees C, which is slightly higher than that for wild-type, whereas VLPs of the D130N mutant could not tolerate the thermal effects at a temperature higher than 60 degrees C. It was deduced that the three aspartate residues of the motif DxxDxD are all important for the efficient formation of DGNNV VLPs and that, among them, the DxxD provides a more stable coordinate of calcium ligand than DxD.
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Affiliation(s)
- Yi-Min Wu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, ROC
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44
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Chen YM, Su YL, Shie PS, Huang SL, Yang HL, Chen TY. Grouper Mx confers resistance to nodavirus and interacts with coat protein. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2008; 32:825-836. [PMID: 18222539 DOI: 10.1016/j.dci.2007.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 12/03/2007] [Accepted: 12/06/2007] [Indexed: 05/25/2023]
Abstract
Over-expression of grouper Mx negatively regulated nodavirus activity through direct interaction, likely via the binding and perturbation of the intracellular localization of nodavirus coat protein. Deletion analysis of grouper Mx indicated that the coat protein binds to the effector domain of Mx. The presence of grouper Mx in a poly [I:C] interferon system inhibited nodavirus infection, demonstrating that grouper Mx over-expression has an inhibitory effect on both coat protein and RNA-dependent RNA polymerase of nodavirus antigens, which results in reduced viral yields. We conclude that grouper Mx has a key role in cellular resistance to nodavirus infection.
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Affiliation(s)
- Young-Mao Chen
- Laboratory of Molecular Genetics, Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
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45
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Adachi K, Ichinose T, Watanabe K, Kitazato K, Kobayashi N. Potential for the replication of the betanodavirus redspotted grouper nervous necrosis virus in human cell lines. Arch Virol 2007; 153:15-24. [PMID: 17906832 PMCID: PMC7086817 DOI: 10.1007/s00705-007-1051-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 07/24/2007] [Indexed: 11/25/2022]
Abstract
The determination of the host ranges of viruses is important because of the possible emergence of infectious agents, which may result from the zoonotic transmission of animal viruses to humans. The family Nodaviridae, whose members are non-enveloped, positive-stranded bipartite RNA viruses, is comprised of the genera Alphanodavirus and Betanodavirus, whose members predominantly infect insects and fish, respectively. The alphanodaviruses can also infect suckling mice and suckling hamsters, resulting in paralysis and death. Pigs near the site of isolation of the Nodamura virus (NoV), an alphanodavirus, have been reported to have high levels of NoV neutralizing antibody, suggesting that they may be part of the natural host range of this virus. Betanodaviruses are the causative agents of viral nervous necrosis, which occurs in several species of fish. However, little is known regarding the mechanism of infection of these viruses. Whether betanodaviruses can infect hosts other than fish remains unclear. In this study, we examined the possibility that a betanodavirus, redspotted grouper nervous necrosis virus (RGNNV), can infect human cell lines and showed that this virus can attach to the cells but cannot penetrate them, although human cells can support the replication of the betanodavirus when viral RNAs are transfected. The betanodavirus in its present form cannot infect human cells.
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Affiliation(s)
- K. Adachi
- />Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - T. Ichinose
- />Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - K. Watanabe
- />Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - K. Kitazato
- />Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - N. Kobayashi
- />Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- />Central Research Center, AVSS Corporation, Nagasaki, Japan
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46
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Thiéry R, Cozien J, Cabon J, Lamour F, Baud M, Schneemann A. Induction of a protective immune response against viral nervous necrosis in the European sea bass Dicentrarchus labrax by using betanodavirus virus-like particles. J Virol 2006; 80:10201-7. [PMID: 17005697 PMCID: PMC1617310 DOI: 10.1128/jvi.01098-06] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2006] [Accepted: 07/26/2006] [Indexed: 11/20/2022] Open
Abstract
Betanodaviruses are causative agents of viral nervous necrosis (VNN), a devastating disease of cultured marine fish worldwide. Virus particles contain a single type of coat protein that spontaneously assembles into virus-like particles (VLPs) when expressed in a baculovirus expression system. In the present study, the immunogenicity of betanodavirus VLPs and the protection they confer against VNN in the European sea bass Dicentrarchus labrax were investigated. Enzyme-linked immunosorbent assay and seroneutralization tests performed on plasma from fish vaccinated intramuscularly with doses as low as 0.1 microg of VLPs indicated that the VLPs elicited the synthesis of specific antibetanodavirus antibodies with neutralizing activity. Moreover, fish vaccinated with VLPs were protected from challenge with live virus. Both the immune response and the protective effect against viral challenge were dose dependent. Reverse transcription-PCR data indicated that higher doses of vaccine also reduced the number of fish containing detectable quantities of betanodavirus RNA on day 30 after challenge. Taken together these data strongly support the hypothesis that VLPs obtained in the baculovirus expression system may represent an effective vaccine against VNN.
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Affiliation(s)
- R Thiéry
- French Food Safety Agency, BP111, F-06902 Sophia Antipolis, France.
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47
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Liu W, Hsu CH, Chang CY, Chen HH, Lin CS. Immune response against grouper nervous necrosis virus by vaccination of virus-like particles. Vaccine 2006; 24:6282-7. [PMID: 16797803 DOI: 10.1016/j.vaccine.2006.05.073] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Revised: 05/08/2006] [Accepted: 05/23/2006] [Indexed: 10/24/2022]
Abstract
The grouper is a high-value fish in the seafood market. Grouper nervous necrosis virus (GNNV) causes mass mortality, near 100% in larvae and juveniles, which has great economic impact on the aquaculture of the marine fish. Since vaccination is one of the best methods against viral diseases, grouper Epinephelus lanceolatus was injected with virus-like particles (VLPs) of GNNV at different dosages and injection frequencies. The anti-sera of vaccinated fish were analyzed with antigen-capture ELISA to quantify immunization titer. The antibody titers in the vaccinated fish increased remarkably within 4 weeks, during which time the antibody was definitely capable to neutralize the native virus. With one shot of 10-250 microg VLPs, the stimulated antibody titer reached a steady saturation level in 1 month, among which the titers by one shot of 100 and 250 microg VLPs were 13% higher than by 10 microg. Two shots of 10 and 100 microg VLPs increased to maximum titer, which was 29% higher than one shot, whereas two shots of 250 microg VLPs and four shots of 100 microg VLPs dramatically downgraded the titers by -23% and -44%, respectively. These results imply that the overdose effects occurred in total dosages higher than 200 microg VLPs. The experiments of VLP vaccine with adjuvant revealed that the adjuvant is not required for increasing the efficacy of the VLP vaccine. Immunization with the VLPs can also stimulate fish to produce high antibody titer for more than 5 months, which can be correlated to long-term protection. When VLPs are used as vaccine agent, a dosage at 1 microg/g of fish body weight is enough to stimulate a full-scale immune response.
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Affiliation(s)
- Wangta Liu
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
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48
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Toffolo V, Negrisolo E, Maltese C, Bovo G, Belvedere P, Colombo L, Dalla Valle L. Phylogeny of betanodaviruses and molecular evolution of their RNA polymerase and coat proteins. Mol Phylogenet Evol 2006; 43:298-308. [PMID: 16990016 DOI: 10.1016/j.ympev.2006.08.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 07/31/2006] [Accepted: 08/01/2006] [Indexed: 01/01/2023]
Abstract
The betanodaviruses are the causative agent of the disease viral nervous necrosis in fishes. Betanodavirus genome consists of two single-stranded positive-sense RNA molecules (RNA1 and RNA2). RNA1 gene encodes the RNA polymerase, named also protein A, while RNA2 encodes the coat protein precursor, the CPp protein. We investigated the evolutionary relationships among betanodaviruses working on partial sequences of both RNA1 and RNA2. Phylogenetic analyses were performed by applying a maximum likelihood approach. The phylogenetic relationships among the major betanodavirus clades SJNNV-IV, TPNNV-III, BFNNV-II and RGNNV-I were resolved differently in the trees obtained, respectively, from RNA1 and RNA2 multiple alignments. The alternative topologies were corroborated by strong bootstrap values. The molecular evolution of proteins A and CPp was also investigated. Protein A appeared to have evolved under strong purifying selection while the CPp protein was subject to both purifying and neutral selection in different amino acid residues. Intragenic recombination in RNA1 and RNA2 genes was investigated by applying several methods and was not detected. Conversely reassortment of RNA1 and RNA2 genes was demonstrated in some isolates. Finally RNA1 and RNA2 genes substitution rates do not follow a clock-like behavior thus impeding estimation of a possible origin time for Betanodavirus genus.
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Affiliation(s)
- Vania Toffolo
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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49
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Liu C, Zhang J, Wang J, Lu J, Chen W, Cai D, Hu Y. Sequence analysis of coat protein gene of Wuhan nodavirus isolated from insect. Virus Res 2006; 121:17-22. [PMID: 16644053 DOI: 10.1016/j.virusres.2006.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 03/12/2006] [Accepted: 03/17/2006] [Indexed: 10/24/2022]
Abstract
Wuhan nodavirus (WhNV) particles are isometric, non-enveloped, and about 29 nm in diameter. In the previous study, we determine its physiochemical characterization and the nucleotide sequence of the larger genomic segment, RNA1 and identify it a nodavirus. WhNV RNA1 is 3,149 nt in length, encoding protein A, catalytic subunit of RNA-dependent RNA polymerase (RdRp). In this report, we complete the sequence determination of the smaller genomic segment, RNA2 of WhNV. WhNV RNA2 is determined to be 1,562 nt long, containing a 430-amino-acid open reading frame (ORF) encoding the coat protein of WhNV with a calculated molecular mass of 47,856 Da. The homology of the coat protein of WhNV and the homologous proteins of other nodaviruses either alphanodaviruses or betanodaviruses is very low. WhNV coat protein shares the highest identity (24%) with that of Lates calcarifer encephalitis virus (LCEV), a betanodavirus, and shares less than 16% identical amino acids with each of the alphanodaviruses. Furthermore, the prediction of WhNV capsid structure by 3D-PSSM shows that the capsid structure of WhNV resembles that of tomato bushy stunt virus (TBSV), a tombusvirus, which contains two domains, rather than the expected single-domain capsid protein of insect nodaviruses. The phylogenetic analysis indicates that WhNV is the most distantly related of both the alphanodaviruses and betanodaviruses, which provides significant new data for understanding the evolution of the nodavirus family.
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Affiliation(s)
- Chuanfeng Liu
- Laboratory of Insect Virology, State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan 430072, China
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50
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Kar AK, Iwatani N, Roy P. Assembly and intracellular localization of the bluetongue virus core protein VP3. J Virol 2005; 79:11487-95. [PMID: 16103199 PMCID: PMC1193605 DOI: 10.1128/jvi.79.17.11487-11495.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bluetongue virus (BTV) core protein VP3 plays a crucial role in the virion assembly and replication process. Although the structure of the protein is well characterized, much less is known about the intracellular processing and localization of the protein in the infected host cell. In BTV-infected cells, newly synthesized viral core particles accumulate in specific locations within the host cell in structures known as virus inclusion bodies (VIBs), which are composed predominantly of the nonstructural protein NS2. However, core protein location in the absence of VIBs remains unclear. In this study, we examined VP3 location and degradation both in the absence of any other viral protein and in the presence of NS2 or the VP3 natural associate protein, VP7. To enable real-time tracking and processing of VP3 within the host cell, a fully functional enhanced green fluorescent protein (EGFP)-VP3 chimera was synthesized, and distribution of the fusion protein was monitored in different cell types using specific markers and inhibitors. In the absence of other BTV proteins, EGFP-VP3 exhibited distinct cytoplasmic focus formation. Further evidence suggested that EGFP-VP3 was targeted to the proteasome of the host cells but was dispersed throughout the cytoplasm when MG132, a specific proteasome inhibitor, was added. However, the distribution of the chimeric EGFP-VP3 protein was altered dramatically when the protein was expressed in the presence of the BTV core protein VP7, a normal partner of VP3 during BTV assembly. Interaction of EGFP-VP3 and VP7 and subsequent assembly of core-like particles was further examined by visualizing fluorescent particles and was confirmed by biochemical analysis and by electron microscopy. These data indicated the correct assembly of EGFP-VP3 subcores, suggesting that core formation could be monitored in real time. When EGFP-VP3 was expressed in BTV-infected BSR cells, the protein was not associated with proteasomes but instead was distributed within the BTV inclusion bodies, where it colocalized with NS2. These findings expand our knowledge about VP3 localization and its fate within the host cell and illustrate the assembly capability of a VP3 molecule with a large amino-terminal extension. This also opens up the possibility of application as a delivery system.
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Affiliation(s)
- Alak Kanti Kar
- Department of Medicine, University of Alabama at Birmingham, 35294, USA
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