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Legisa D, Gonzalez F, De Stefano G, Pereda A, Santos MJD. Phylogenetic analysis of bluetongue virus serotype 4 field isolates from Argentina. J Gen Virol 2013; 94:652-662. [DOI: 10.1099/vir.0.046896-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bluetongue is an insect-transmitted viral disease of ruminant species, which represents a major barrier to the international trade of animals and their products. Bluetongue virus (BTV) has a genome composed of ten linear segments of dsRNA, which code for at least ten different viral proteins. In South America, serological evidence for the presence of BTV has been found in Peru, Argentina, Brazil, Ecuador and Chile. Brazil and Argentina are the only South American countries where BTV has been isolated. In Brazil, only one BTV isolate, serotype 12, has been reported, whereas in Argentina five BTV serotype 4 isolates have been obtained from cattle without clinical signs. Three of these five isolates were isolated during 1999–2001, whereas two of them were obtained as part of the present work. This study describes sequence comparisons and phylogenetic analyses of segment (Seg)-2, Seg-3, Seg-6, Seg-7 and Seg-10 of the first Argentinian field isolates of BTV. The analysis of Seg-2 and Seg-6 resulted in a single cluster of Argentinian sequences into the serotype 4 clade. In addition, the Argentinian sequences grouped within the nucleotype A clade, along with reference strains. The analysis of Seg-3, Seg-7 and Seg-10 showed that the Argentinian isolates grouped into the western topotype, indicating that the circulating virus had an African/European origin. Phylogenetic analysis revealed that the Argentinian sequences present a South American genetic identity, suggesting an independent lineage evolution.
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Affiliation(s)
- D. Legisa
- Instituto de Virología, CICVyA, INTA-Castelar, Buenos Aires, Argentina
| | - F. Gonzalez
- Instituto de Virología, CICVyA, INTA-Castelar, Buenos Aires, Argentina
| | - G. De Stefano
- Instituto de Virología, CICVyA, INTA-Castelar, Buenos Aires, Argentina
| | - A. Pereda
- Instituto de Virología, CICVyA, INTA-Castelar, Buenos Aires, Argentina
| | - M. J. Dus Santos
- Instituto de Virología, CICVyA, INTA-Castelar, Buenos Aires, Argentina
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Li JKK. Oncolytic bluetongue viruses: promise, progress, and perspectives. Front Microbiol 2011; 2:46. [PMID: 21747785 PMCID: PMC3128942 DOI: 10.3389/fmicb.2011.00046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 03/01/2011] [Indexed: 11/26/2022] Open
Abstract
Humans are sero-negative toward bluetongue viruses (BTVs) since BTVs do not infect normal human cells. Infection and selective degradation of several human cancer cell lines but not normal ones by five US BTV serotypes have been investigated. We determined the susceptibilities of many normal and human cancer cells to BTV infections and made comparative kinetic analyses of their cytopathic effects, survival rates, ultra-structural changes, cellular apoptosis and necrosis, cell cycle arrest, cytokine profiles, viral genome, mRNAs, and progeny titers. The wild-type US BTVs, without any genetic modifications, could preferentially infect and degrade several types of human cancer cells but not normal cells. Their selective and preferential BTV-degradation of human cancer cells is viral dose–dependent, leading to effective viral replication, and induced apoptosis. Xenograft tumors in mice were substantially reduced by a single intratumoral BTV injection in initial in vivo experiments. Thus, wild-type BTVs, without genetic modifications, have oncolytic potentials. They represent an attractive, next generation of oncolytic viral approach for potential human cancer therapy combined with current anti-cancer agents and irradiation.
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Affiliation(s)
- Joseph K-K Li
- Department of Biology, Utah State University Logan, UT, USA
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3
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Bhattacharya B, Roy P. Role of lipids on entry and exit of bluetongue virus, a complex non-enveloped virus. Viruses 2010; 2:1218-1235. [PMID: 21994677 PMCID: PMC3187602 DOI: 10.3390/v2051218] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 05/04/2010] [Accepted: 05/11/2010] [Indexed: 11/16/2022] Open
Abstract
Non-enveloped viruses such as members of Picornaviridae and Reoviridae are assembled in the cytoplasm and are generally released by cell lysis. However, recent evidence suggests that some non-enveloped viruses exit from infected cells without lysis, indicating that these viruses may also utilize alternate means for egress. Moreover, it appears that complex, non-enveloped viruses such as bluetongue virus (BTV) and rotavirus interact with lipids during their entry process as well as with lipid rafts during the trafficking of newly synthesized progeny viruses. This review will discuss the role of lipids in the entry, maturation and release of non-enveloped viruses, focusing mainly on BTV.
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Affiliation(s)
| | - Polly Roy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44 (0)20 7927 2324; Fax: +44 (0)20 7927 2324
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Nomikou K, Dovas CΙ, Maan S, Anthony SJ, Samuel AR, Papanastassopoulou M, Maan NS, Mangana O, Mertens PPC. Evolution and phylogenetic analysis of full-length VP3 genes of Eastern Mediterranean bluetongue virus isolates. PLoS One 2009; 4:e6437. [PMID: 19649272 PMCID: PMC2713410 DOI: 10.1371/journal.pone.0006437] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 05/02/2009] [Indexed: 11/19/2022] Open
Abstract
Bluetongue virus (BTV) is the ‘type’ species of the genus Orbivirus within the family Reoviridae. The BTV genome is composed of ten linear segments of double-stranded RNA (dsRNA), each of which codes for one of ten distinct viral proteins. Previous phylogenetic comparisons have evaluated variations in genome segment 3 (Seg-3) nucleotide sequence as way to identify the geographical origin (different topotypes) of BTV isolates. The full-length nucleotide sequence of genome Seg-3 was determined for thirty BTV isolates recovered in the eastern Mediterranean region, the Balkans and other geographic areas (Spain, India, Malaysia and Africa). These data were compared, based on molecular variability, positive-selection-analysis and maximum-likelihood phylogenetic reconstructions (using appropriate substitution models) to 24 previously published sequences, revealing their evolutionary relationships. These analyses indicate that negative selection is a major force in the evolution of BTV, restricting nucleotide variability, reducing the evolutionary rate of Seg-3 and potentially of other regions of the BTV genome. Phylogenetic analysis of the BTV-4 strains isolated over a relatively long time interval (1979–2000), in a single geographic area (Greece), showed a low level of nucleotide diversity, indicating that the virus can circulate almost unchanged for many years. These analyses also show that the recent incursions into south-eastern Europe were caused by BTV strains belonging to two different major-lineages: representing an ‘eastern’ (BTV-9, -16 and -1) and a ‘western’ (BTV-4) group/topotype. Epidemiological and phylogenetic analyses indicate that these viruses originated from a geographic area to the east and southeast of Greece (including Cyprus and the Middle East), which appears to represent an important ecological niche for the virus that is likely to represent a continuing source of future BTV incursions into Europe.
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Affiliation(s)
- Kyriaki Nomikou
- Arbovirus Molecular Research Group, Department of vector borne diseases, Institute for Animal Health, Pirbright Laboratory, Woking, Surrey, United Kingdom
- Virus Laboratory, Institute of Infectious and Parasitic Diseases, Ministry of Rural Development and Food, Athens, Greece
| | - Chrysostomos Ι. Dovas
- Department of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Sushila Maan
- Arbovirus Molecular Research Group, Department of vector borne diseases, Institute for Animal Health, Pirbright Laboratory, Woking, Surrey, United Kingdom
| | - Simon J. Anthony
- Wildlife Disease Laboratory, San Diego Zoo Conservation Research, Escondido, California, United States of America
| | - Alan R. Samuel
- Arbovirus Molecular Research Group, Department of vector borne diseases, Institute for Animal Health, Pirbright Laboratory, Woking, Surrey, United Kingdom
| | - Maria Papanastassopoulou
- Department of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Narender S. Maan
- Arbovirus Molecular Research Group, Department of vector borne diseases, Institute for Animal Health, Pirbright Laboratory, Woking, Surrey, United Kingdom
| | - Olga Mangana
- Virus Laboratory, Institute of Infectious and Parasitic Diseases, Ministry of Rural Development and Food, Athens, Greece
| | - Peter P. C. Mertens
- Arbovirus Molecular Research Group, Department of vector borne diseases, Institute for Animal Health, Pirbright Laboratory, Woking, Surrey, United Kingdom
- * E-mail:
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Bluetongue virus outer capsid protein VP5 interacts with membrane lipid rafts via a SNARE domain. J Virol 2008; 82:10600-12. [PMID: 18753209 DOI: 10.1128/jvi.01274-08] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bluetongue virus (BTV) is a nonenveloped double-stranded RNA virus belonging to the family Reoviridae. The two outer capsid proteins, VP2 and VP5, are responsible for virus entry. However, little is known about the roles of these two proteins, particularly VP5, in virus trafficking and assembly. In this study, we used density gradient fractionation and methyl beta cyclodextrin, a cholesterol-sequestering drug, to demonstrate not only that VP5 copurifies with lipid raft domains in both transfected and infected cells, but also that raft domain integrity is required for BTV assembly. Previously, we showed that BTV nonstructural protein 3 (NS3) interacts with VP2 and also with cellular exocytosis and ESCRT pathway proteins, indicating its involvement in virus egress (A. R. Beaton, J. Rodriguez, Y. K. Reddy, and P. Roy, Proc. Natl. Acad. Sci. USA 99:13154-13159, 2002; C. Wirblich, B. Bhattacharya, and P. Roy J. Virol. 80:460-473, 2006). Here, we show by pull-down and confocal analysis that NS3 also interacts with VP5. Further, a conserved membrane-docking domain similar to the motif in synaptotagmin, a protein belonging to the SNARE (soluble N-ethylmaleimide-sensitive fusion attachment protein receptor) family was identified in the VP5 sequence. By site-directed mutagenesis, followed by flotation and confocal analyses, we demonstrated that raft association of VP5 depends on this domain. Together, these results indicate that VP5 possesses an autonomous signal for its membrane targeting and that the interaction of VP5 with membrane-associated NS3 might play an important role in virus assembly.
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Roner MR, Steele BG. Features of the mammalian orthoreovirus 3 Dearing l1 single-stranded RNA that direct packaging and serotype restriction. J Gen Virol 2008; 88:3401-3412. [PMID: 18024910 DOI: 10.1099/vir.0.83209-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A series of recombinant mammalian orthoreoviruses (mammalian orthoreovirus 3 Dearing, MRV-3De) were generated that express an MRV-3De lambda3-CAT fusion protein. Individual viruses contain L1CAT double-stranded (ds) RNAs that range in length from a minimum of 1020 bp to 4616 bp. The engineered dsRNAs were generated from in vitro-transcribed single-stranded (ss) RNAs and incorporated into infectious virus particles by using reverse genetics. In addition to defining the sequences required for these ssRNAs to be 'identified' as l1 ssRNAs, the individual nucleotides in these regions that 'mark' each ssRNA as originating from mammalian orthoreovirus 1 Lang (MRV-1La), mammalian orthoreovirus 2 D5/Jones (MRV-2Jo) or MRV-3De have been identified. A C at position 81 in the MRV-1La 5' 129 nt sequence was able to be replaced with a U, as normally present in MRV-3De; this toggled the activity of the MRV-1La ssRNA to that of an MRV-3De 5' l1. RNA secondary-structure predictions for the 5' 129 nt of both the biologically active MRV-3De l1 ssRNA and the U81-MRV-3De-restored MRV-1La 5' ssRNA predicted a common structure.
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Affiliation(s)
- Michael R Roner
- Department of Biology, The University of Texas Arlington, Arlington, TX 76019, USA
| | - Bradley G Steele
- Department of Biology, The University of Texas Arlington, Arlington, TX 76019, USA
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Bhattacharya B, Noad RJ, Roy P. Interaction between Bluetongue virus outer capsid protein VP2 and vimentin is necessary for virus egress. Virol J 2007; 4:7. [PMID: 17224050 PMCID: PMC1783847 DOI: 10.1186/1743-422x-4-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Accepted: 01/15/2007] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The VP2 outer capsid protein Bluetongue Virus (BTV) is responsible for receptor binding, haemagglutination and eliciting host-specific immunity. However, the assembly of this outer capsid protein on the transcriptionally active viral core would block transcription of the virus. Thus assembly of the outer capsid on the core particle must be a tightly controlled process during virus maturation. Earlier studies have detected mature virus particles associated with intermediate filaments in virus infected cells but the viral determinant for this association and the effect of disrupting intermediate filaments on virus assembly and release are unknown. RESULTS In this study it is demonstrated that BTV VP2 associates with vimentin in both virus infected cells and in the absence of other viral proteins. Further, the determinants of vimentin localisation are mapped to the N-terminus of the protein and deletions of amino acids between residues 65 and 114 are shown to disrupt VP2-vimentin association. Site directed mutation also reveals that amino acid residues Gly 70 and Val 72 are important in the VP2-vimentin association. Mutation of these amino acids resulted in a soluble VP2 capable of forming trimeric structures similar to unmodified protein that no longer associated with vimentin. Furthermore, pharmacological disruption of intermediate filaments, either directly or indirectly through the disruption of the microtubule network, inhibited virus release from BTV infected cells. CONCLUSION The principal findings of the research are that the association of mature BTV particles with intermediate filaments are driven by the interaction of VP2 with vimentin and that this interaction contributes to virus egress. Furthermore, i) the N-terminal 118 amino acids of VP2 are sufficient to confer vimentin interaction. ii) Deletion of amino acids 65-114 or mutation of amino acids 70-72 to DVD abrogates vimentin association. iii) Finally, disruption of vimentin structures results in an increase in cell associated BTV and a reduction in the amount of released virus from infected cells.
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Affiliation(s)
- Bishnupriya Bhattacharya
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
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Roy P. Bluetongue virus proteins and particles and their role in virus entry, assembly, and release. Adv Virus Res 2005; 64:69-123. [PMID: 16139593 DOI: 10.1016/s0065-3527(05)64004-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Polly Roy
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
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9
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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: 23] [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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Palucha A, Loniewska A, Satheshkumar S, Boguszewska-Chachulska AM, Umashankar M, Milner M, Haenni AL, Savithri HS. Virus-like particles: models for assembly studies and foreign epitope carriers. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2005; 80:135-68. [PMID: 16164974 PMCID: PMC7119358 DOI: 10.1016/s0079-6603(05)80004-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Virus‐like particles (VLPs), formed by the structural elements of viruses, have received considerable attention over the past two decades. The number of reports on newly obtained VLPs has grown proportionally with the systems developed for the expression of these particles. The chapter outlines the recent achievements in two important fields of research brought about by the availability of VLPs produced in a foreign host. These are: (1) The requirements for VLP assembly and (2) the use of VLPs as carriers for foreign epitopes. VLP technology is a rapidly advancing domain of molecular and structural biology. Extensive progress in VLP studies was achieved as the insect cell based protein production system was developed. This baculovirus expression system has many advantages for the synthesis of viral structural proteins resulting in the formation of VLPs. It allows production of large amounts of correctly folded proteins while also providing cell membranes that can serve as structural elements for enveloped viruses. These features give us the opportunity to gain insights into the interactions and requirements accompanying VLP formation that are similar to the assembly events occurring in mammalian cells. Other encouraging elements are the ability to easily scale up the system and the simplicity of purification of the assembled VLPs. The growing number of VLPs carrying foreign protein fragments on their surface and studies on the successful assembly of these chimeric molecules is a promising avenue towards the development of a new technology, in which the newly designed VLPs will be directed to particular mammalian cell types by exposing specific binding domains. The progress made in modeling the surface of VLPs makes them to date the best candidates for the design of delivery systems that can efficiently reach their targets.
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Affiliation(s)
- Andrzej Palucha
- Institute of Biochemistry and Biophysics, Pawinskiego 5a, 02-106 Warszawa, Poland
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11
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Kar AK, Ghosh M, Roy P. Mapping the assembly pathway of Bluetongue virus scaffolding protein VP3. Virology 2004; 324:387-99. [PMID: 15207624 DOI: 10.1016/j.virol.2004.04.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2004] [Revised: 03/31/2004] [Accepted: 04/13/2004] [Indexed: 11/19/2022]
Abstract
The structure of the Bluetongue virus (BTV) core and its outer layer VP7 has been solved by X-ray crystallography, but the assembly intermediates that lead to the inner scaffolding VP3 layer have not been defined. In this report, we addressed two key questions: (a) the role of VP3 amino terminus in core assembly and its interaction with the transcription complex (TC) components; and (b) the assembly intermediates involved in the construction of the VP3 shell. To do this, deletion mutants in the amino terminal and decamer-decamer interacting region of VP3 (DeltaDD) were generated, expressed in insect cells using baculovirus expression systems, and their ability to assemble into core-like particles (CLPs) and to incorporate the components of TC were investigated. Deletion of the N-terminal 5 (Delta5N) or 10 (Delta10N) amino acids did not affect the ability to assemble into CLPs in the presence of VP7 although the cores assembled using the 10 residue mutant (Delta10N) deletion were very unstable. Removal of five residues also did not effect incorporation of the internal VP1 RNA polymerase and VP4 mRNA capping enzyme proteins of the TC. Removal of the VP3-VP3 interacting domain (DeltaDD) led to failure to assemble into CLPs yet retained interaction with VP1 and VP4. In solution, purified DeltaDD mutant protein readily multimerized into dimers, pentamers, and decamers, suggesting that these oligomers are the authentic assembly intermediates of the subcore. However, unlike wild-type VP3 protein, the dimerization domain-deleted assembly intermediates were found to have lost RNA binding ability. Our study emphasizes the requirement of the N-terminus of VP3 for binding and encapsidation of the TC components, and defines the role of the dimerization domain in subcore assembly and RNA binding.
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Affiliation(s)
- Alak Kanti Kar
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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12
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Limn CK, Roy P. Intermolecular interactions in a two-layered viral capsid that requires a complex symmetry mismatch. J Virol 2003; 77:11114-24. [PMID: 14512559 PMCID: PMC224973 DOI: 10.1128/jvi.77.20.11114-11124.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The surface of the bluetongue virus core forms a T=13 quasiequivalent icosahedral protein shell with 260 trimers of a single gene product: VP7 protein. Underneath is a smooth layer, made up of VP3 protein, which appears to guide and nucleate the assembly of VP7 trimers. The contacts between the two shells are extensive but nonspecific, and construction of the T=13 icosahedral shell requires polymorphism in the association of the VP7 subunits, each of which has two domains that contribute to trimer formation. We used structural and relative sequence information to guide an investigation of how such a complex structure is achieved during virus assembly and what residues are required to form a stable capsid. Fifteen single or multiple site-specific substitution mutations were introduced into the helical domain of VP7, which is closely associated with the VP3 layer, and the effects on capsid assembly were analyzed. Our data show that both the position and the nature of single residues are critical for the attachment of VP7 to VP3 and that formation of a stable VP7 lattice is not the automatic consequence of trimer formation.
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Affiliation(s)
- Chang-Kwang Limn
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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13
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Iwata H, Manabe S, Yoshida A, Pereira EM, Inoue T. The complete nucleotide sequences of L3 and S7 segments of Ibaraki virus encoding for the major inner capsid proteins, VP3 and VP7. J Vet Med Sci 2001; 63:73-8. [PMID: 11217068 DOI: 10.1292/jvms.63.73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The complete nucleotide sequences of the genes encoding two of the major inner capsid proteins of Ibaraki virus (IBAV), belonging to epizootic hemorrhagic disease virus serotype 2 (EHDV-2) were determined. The L3 RNA segment is 2768 nucleotides in length which encodes VP3 polypeptides of 899 amino acid residues (M.W. 103 kDa). The S7 RNA segment, which encodes the VP7 core protein, is 1162 nucleotides in length and encodes 349 amino acids (M.W. 38 kDa). These RNA segments had the characteristic consensus motifs of Orbivirus RNA segments in termini, namely 5'-GUUAAA... and ...ACUUAC-3'. The comparison of the IBAV L3 and S7 sequences with those of other two EHDV-2 isolates revealed the higher homologies of 93% and 92% against EHDV-2 Australia isolate (EHDV-2AUS) and lower homologies of 80% and 81% against EHDV-2 North America isolate, respectively. The phylogenetic analysis based on L3 and S7 genes also indicated close relationships between IBAV and EHDV-2AUS.
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Affiliation(s)
- H Iwata
- Department of Veterinary Hygiene, Faculty of Agriculture, Yamaguchi University, Japan
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14
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Zheng YZ, Greenfield PF, Reid S. Optimized production of recombinant bluetongue core-like particles produced by the baculovirus expression system. Biotechnol Bioeng 1999; 65:600-4. [PMID: 10516586 DOI: 10.1002/(sici)1097-0290(19991205)65:5<600::aid-bit13>3.0.co;2-k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The baculovirus-expression vector system (BEVS) has been widely used for the experimental production of many human and animal single- and multi-unit vaccines, heterologous proteins, and viral insecticides. In this work, the production of recombinant bluetongue virus core-like particles (CLPs), using Sf9 cells in shaker-suspension culture with the SF900 II medium (GIBCO, NY), has been studied. This system involved the simultaneous production of two proteins, VP7 and VP3, and was shown to achieve high volumetric productivities. The key parameters of the time of infection (TOI), and the multiplicity of infection (MOI) were studied. The results show that the peak-volumetric yields and cell-specific yields achieved using low MOIs at low-cell densities were the same as those obtained following infections with a high MOI at high-cell densities. This work establishes the feasibility of using low MOIs in the baculovirus system to produce complex multiprotein particles.
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Affiliation(s)
- Y Z Zheng
- Department of Chemical Engineering, The University of Queensland, QLD, 4072, Australia.
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15
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Ulrich R, Nassal M, Meisel H, Krüger DH. Core particles of hepatitis B virus as carrier for foreign epitopes. Adv Virus Res 1998; 50:141-82. [PMID: 9520999 DOI: 10.1016/s0065-3527(08)60808-8] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To be effective as vaccines, most monomeric proteins and peptides either require chemical coupling to high molecular weight carriers or application together with adjuvants. More recently, recombinant DNA techniques have been used to insert foreign epitopes into proteins with inherent multimerization capacity, such as particle-forming viral capsid or envelope proteins. The core protein of hepatitis B virus (HBcAg), because of its unique structural and immunological properties, has gained widespread interest as a potential antigen carrier. Foreign sequences of up to approximately 40 amino acid residues at the N terminus, 50 or 100 amino acids in the central immunodominant c/e 1 epitope region of HBcAg, and up to 100 or even more residues at the C terminus, did not interfere with particle formation. The humoral immunogenicity of inserted epitopes is determined by the immunogenicity of the peptide itself and its surface exposure, and is influenced by the route of application. The probably flexible and surface-exposed c/e1 region emerged as the most promising insertion site. When applied together with adjuvants approved for human and veterinary use, or even without adjuvants, such chimeric particles induced B and T cell immune responses against the inserted epitopes. In some cases neutralizing antibodies, cytotoxic T cells and protection against challenge with the intact pathogen were demonstrated. Major factors for the potentiated immune response against the foreign epitopes are the multimeric structure of chimeric HBcAg that results in a high epitope density per particle, and the provision of T cell help by the carrier moiety. Beyond its use as subunit vaccine, chimeric HBcAg produced in attenuated Salmonella strains may be applicable as live vaccine.
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Affiliation(s)
- R Ulrich
- Charité Medical School, Humboldt University, Berlin, Germany
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Roy P, Mikhailov M, Bishop DH. Baculovirus multigene expression vectors and their use for understanding the assembly process of architecturally complex virus particles. Gene 1997; 190:119-29. [PMID: 9185857 DOI: 10.1016/s0378-1119(96)00619-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The baculovirus expression vector is a eukaryotic DNA viral vector for the cloning and expression of foreign genes in cultured lepidopteran insect cells and insects. It has become an important tool for the large-scale production of recombinant proteins for a variety of applications including the structure-function analysis of genes and their gene products. We have developed a number of baculovirus multigene expression vectors and utilized these to understand the assembly process of multicomponent capsid structures of large viruses such as bluetongue virus (BTV), a member of the Orbivirus genus within the family Reoviridae. BTV is some 810 A in diameter and comprised of two protein shells containing four major proteins, VP2, VP5, VP7 and VP3, surrounding a genome of ten double-stranded RNA segments and three minor proteins (VP2, VP4 and VP6). BTV is the etiological agent of a sheep disease that is sometimes fatal in certain parts of the world (e.g., Africa, Asia, and the Americas). Using baculovirus multigene vectors, we have co-expressed various combinations of BTV genes in insect cells and produced structures that mimic the various stages of BTV assembly. For example, co-expressed VP3 and VP7 form BTV core-like particles, while co-expressed VP2, VP5, VP7 and VP3 form BTV virus-like particles. Using deletion, point and domain switching analyses of each protein, we have been able to identify certain sequences in the VP7 and VP3 proteins that are essential for the assembly of core-like particles. These expression and biochemical studies have been complemented by collaboration studies using cryo-electron microscopy and image processing analyses to provide the three-dimensional structure of the expressed particles. In addition and with other associates, we have used X-ray crystallography of VP7 to deduce its atomic structure. Extensive studies on the immune responses elicited by these self-assembled particles, and chimeric derivatives involving various foreign antigens, have been carried out. Finally, using as little as 10 microg of the self-assembled virus-like particles, we have shown that they can confer long-lasting protection in sheep against BTV.
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Affiliation(s)
- P Roy
- Department of Biochemistry, University of Oxford, UK.
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