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Espen Rimstad - One of the best experts on this subject based on the ideXlab platform.
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dna vaccine expressing the non structural proteins of piscine Orthoreovirus delay the kinetics of prv infection and induces moderate protection against heart and skeletal muscle inflammation in atlantic salmon salmo salar
Vaccine, 2018Co-Authors: Hanne Merethe Haatveit, Ingvild Berg Nyman, Maria K. Dahle, Kjartan Hodneland, Stine Braaen, Elisabeth F Hansen, Petter Frost, Espen RimstadAbstract:Abstract Piscine Orthoreovirus (PRV) causes heart- and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). Erythrocytes are the main target cells for PRV. HSMI causes significant economic losses to the salmon aquaculture industry, and there is currently no vaccine available. PRV replicates and assembles within cytoplasmic structures called viral factories, mainly organized by the non-structural viral protein µNS. In two experimental vaccination trials in Atlantic salmon, using DNA vaccines expressing different combinations of PRV proteins, we found that expression of the non-structural proteins µNS combined with the cell attachment protein σ1 was associated with an increasing trend in lymphocyte marker gene expression in spleen, and induced moderate protective effect against HSMI.
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The non-structural protein μNS of piscine Orthoreovirus (PRV) forms viral factory-like structures
Veterinary Research, 2016Co-Authors: Hanne Merethe Haatveit, Maria Krudtaa Dahle, Turhan Markussen, Ingvild B. Nyman, Øystein Wessel, Espen RimstadAbstract:AbstractPiscine Orthoreovirus (PRV) is associated with heart- and skeletal muscle inflammation in farmed Atlantic salmon. The virus is ubiquitous and found in both farmed and wild salmonid fish. It belongs to the family Reoviridae, closely related to the genus Orthoreovirus. The PRV genome comprises ten double-stranded RNA segments encoding at least eight structural and two non-structural proteins. Erythrocytes are the major target cells for PRV. Infected erythrocytes contain globular inclusions resembling viral factories; the putative site of viral replication. For the mammalian reovirus (MRV), the non-structural protein μNS is the primary organizer in factory formation. The analogous PRV protein was the focus of the present study. The subcellular location of PRV μNS and its co-localization with the PRV σNS, µ2 and λ1 proteins was investigated. We demonstrated that PRV μNS forms dense globular cytoplasmic inclusions in transfected fish cells, resembling the viral factories of MRV. In co-transfection experiments with μNS, the σNS, μ2 and λ1 proteins were recruited to the globular structures. The ability of μNS to recruit other PRV proteins into globular inclusions indicates that it is the main viral protein involved in viral factory formation and pivotal in early steps of viral assembly.
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Piscine Orthoreovirus (PRV) infects Atlantic salmon erythrocytes
Veterinary Research, 2014Co-Authors: Øystein Wessel Finstad, Maria Krudtaa Dahle, Tone Hæg Lindholm, Ingvild Berg Nyman, Marie Løvoll, Christian Wallace, Christel Moræus Olsen, Anne K Storset, Espen RimstadAbstract:Piscine Orthoreovirus (PRV) belongs to the Reoviridae family and is the only known fish virus related to the Orthoreovirus genus. The virus is the causative agent of heart and skeletal muscle inflammation (HSMI), an emerging disease in farmed Atlantic salmon (Salmo salar L.). PRV is ubiquitous in farmed Atlantic salmon and high loads of PRV in the heart are consistent findings in HSMI. The mechanism by which PRV infection causes disease remains largely unknown. In this study we investigated the presence of PRV in blood and erythrocytes using an experimental cohabitation challenge model. We found that in the early phases of infection, the PRV loads in blood were significantly higher than in any other organ. Most virus was found in the erythrocyte fraction, and in individual fish more than 50% of erythrocytes were PRV-positive, as determined by flow cytometry. PRV was condensed into large cytoplasmic inclusions resembling viral factories, as demonstrated by immunofluorescence and confocal microscopy. By electron microscopy we showed that these inclusions contained reovirus-like particles. The PRV particles and inclusions also had a striking resemblance to previously reported viral inclusions described as Erythrocytic inclusion body syndrome (EIBS). We conclude that the erythrocyte is a major target cell for PRV infection. These findings provide new information about HSMI pathogenesis, and show that PRV is an important factor of viral erythrocytic inclusions.
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Proteins encoded by the PRV genome and functional properties as predicted from comparative studies with selected reovirus prototype strains.
2013Co-Authors: Turhan Markussen, Soren Grove, Marie Løvoll, Maria K. Dahle, Torstein Tengs, Øystein W. Finstad, Christer R. Wiik-nielsen, Silje Lauksund, Børre Robertsen, Espen RimstadAbstract:aL1-M3 PRV gene segments are annotated according to mammalian reoviruses (MRV). PRV L1 has been changed to L3, and vice versa, compared to that suggested by [1]. PRV S-class gene segments are annotated according to [1]. For mammalian reovirus (MRV), avian Orthoreovirus (ARV) and grass carp reovirus (GCRV) several proteins are produced from alternative reading frames or by post-translational proteolytic cleavage. In the latter case, if the exact cleavage site is known, the lengths of both proteolytic fragments are included in the table.bT3D = Type 3 Dearing strain.cGCRV contains an eleventh genomic segment which encodes a non-structural protein, NS26. VP7 is homologues to σ3/σB.dCytotoxic, nonfusogenic integral membrane protein [96].
Max L Nibert - One of the best experts on this subject based on the ideXlab platform.
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Bioinformatics of Recent Aqua- and Orthoreovirus Isolates from Fish: Evolutionary Gain or Loss of FAST and Fiber Proteins and Taxonomic Implications
PLOS ONE, 2013Co-Authors: Max L Nibert, Roy DuncanAbstract:Family Reoviridae, subfamily Spinareovirinae, includes nine current genera. Two of these genera, Aquareovirus and Orthoreovirus, comprise members that are closely related and consistently share nine homologous proteins. Orthoreoviruses have 10 dsRNA genome segments and infect reptiles, birds, and mammals, whereas aquareoviruses have 11 dsRNA genome segments and infect fish. Recently, the first 10-segmented fish reovirus, piscine reovirus (PRV), has been identified and shown to be phylogenetically divergent from the 11-segmented viruses constituting genus Aquareovirus. We have recently extended results for PRV by showing that it does not encode a fusion-associated small transmembrane (FAST) protein, but does encode an outer-fiber protein containing a long N-terminal region of predicted α-helical coiled coil. Three recently characterized 11-segmented fish reoviruses, obtained from grass carp in China and sequenced in full, are also divergent from the viruses now constituting genus Aquareovirus, though not to the same extent as PRV. In the current study, we reexamined the sequences of these three recent isolates of grass carp reovirus (GCRV)–HZ08, GD108, and 104–for further clues to their evolution relative to other aqua- and Orthoreoviruses. Structure-based fiber motifs in their encoded outer-fiber proteins were characterized, and other bioinformatics analyses provided evidence against the presence of a FAST protein among their encoded nonstructural proteins. Phylogenetic comparisons showed the combination of more distally branching, approved Aquareovirus and Orthoreovirus members, plus more basally branching isolates GCRV104, GCRV-HZ08/GD108, and PRV, constituting a larger, monophyletic taxon not suitably recognized by the current taxonomic hierarchy. Phylogenetics also suggested that the last common ancestor of all these viruses was a fiber-encoding, nonfusogenic virus and that the FAST protein family arose from at least two separate gain-of-function events. In addition, an apparent evolutionary correlation was found between the gain or loss of NS-FAST and outer-fiber proteins among more distally branching members of this taxon.
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Coding strategies of aqua- and Orthoreovirus proteins.
2013Co-Authors: Max L Nibert, Roy DuncanAbstract:aRepresentative strains are Aquareovirus A, strain Scophthalmus maximus reovirus (AqRV-A); Aquareovirus C, strain Golden shiner reovirus (AqRV-C); Aquareovirus G, strain AGCRV-PB01-155 (AqRV-G); tentative Aquareovirus species, strain GCRV-HZ08; tentative Aquareovirus species, strain GCRV104; tentative Orthoreovirus species, strain Reovirus Salmo/GP-2010/NOR (PRV); Mammalian Orthoreovirus, strain Type 1 Lang (MRV); Avian Orthoreovirus, strain 176 (ARV); Baboon Orthoreovirus strain Baboon reovirus (BRV); and tentative Orthoreovirus species, strain Broome virus (BroV). See Table S1 for GenBank accession numbers.bThese proteins are consistently homologous across both genera.
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Comparisons of aqua- and Orthoreovirus FAST proteins.
2013Co-Authors: Max L Nibert, Roy DuncanAbstract:(A) MAFFT alignment of aquareovirus FAST proteins in Clustal format. Residues conserved among AqRV-A isolates in this figure are colored magenta; residues conserved among AqRV-C and AqRV-G isolates are colored red. (B) MAFFT alignment of Orthoreovirus ARV and NBV FAST proteins in Clustal format. Residues conserved among ARV isolates in this figure are colored magenta; residues conserved among ARV isolates are colored red. (C) MAFFT alignment of Orthoreovirus BRV, BroV, and RRV FAST proteins in Clustal format. Residues conserved in BroV and RRV are colored red. In A–C, TMDs predicted by TMHMM are background-shaded in gray; polybasic clusters following the TMDs are background-shaded in yellow. (C) Maximum-likelihood (PhyML 3.0) unrooted phylogram of aqua- and Orthoreovirus FAST proteins. Program-estimated values for invariant proportion and gamma shape parameter were 0.007 and 3.598, respectively. Branches with support values ≥90% are not labeled, and those with support values
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Orthoreovirus and aquareovirus core proteins conserved enzymatic surfaces but not protein protein interfaces
Virus Research, 2004Co-Authors: Yizhi Tao, Jonghwa Kim, Karin M Reinisch, Stephen C Harrison, Max L NibertAbstract:Orthoreoviruses and Aquareoviruses constitute two respective genera in the family Reoviridae of double-stranded RNA viruses. Orthoreoviruses infect mammals, birds, and reptiles and have a genome comprising 10 RNA segments. Aquareoviruses infect fish and have a genome comprising 11 RNA segments. Despite these differences, recent structural and nucleotide sequence evidence indicate that the proteins of Orthoreoviruses and Aquareoviruses share many similarities. The focus of this review is on the structure and function of the Orthoreovirus core proteins 1, 2, 3, and 2, for which X-ray crystal structures have been recently reported. The homologous core proteins in Aquareoviruses are VP3, VP1, VP2, and VP6, respectively. By mapping the locations of conserved residues onto the Orthoreovirus crystal structures, we have found that enzymatic surfaces involved in mRNA synthesis are well conserved between these two groups of viruses, whereas several surfaces involved in protein–protein interactions are not well conserved. Other evidence indicates that the Orthoreovirus 2 and Aquareovirus VP5 proteins are homologous, suggesting that VP5 is a core protein as 2 is known to be. These findings provide further evidence that Orthoreoviruses and Aquareoviruses have diverged from a common ancestor and contribute to a growing understanding of the functions of the core proteins in viral mRNA synthesis. © 2003 Elsevier B.V. All rights reserved.
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Nucleoside and RNA Triphosphatase Activities of Orthoreovirus Transcriptase Cofactor μ2
Journal of Biological Chemistry, 2003Co-Authors: John S. L. Parker, Kenneth E Murray, Max L NibertAbstract:Abstract The mammalian Orthoreovirus (mORV) core particle is an icosahedral multienzyme complex for viral mRNA synthesis and provides a delimited system for mechanistic studies of that process. Previous genetic results have identified the mORV μ 2 protein as a determinant of viral strain differences in the transcriptase and nucleoside triphosphatase activities of cores. New results in this report provided biochemical and genetic evidence that purified μ2 is itself a divalent cation-dependent nucleoside triphosphatase that can remove the 5′ γ-phosphate from RNA as well. Alanine substitutions in a putative nucleotide binding region of μ2 abrogated both functions but did not affect the purification profile of the protein or its known associations with microtubules and mORV μNS protein in vivo. In vitro microtubule binding by purified μ2 was also demonstrated and not affected by the mutations. Purified μ2 was further demonstrated to interact in vitro with the mORV RNA-dependent RNA polymerase, λ3, and the presence of λ3 mildly stimulated the triphosphatase activities of μ2. These findings confirm that μ2 is an enzymatic component of the mORV core and may contribute several possible functions to viral mRNA synthesis.
Hanne Merethe Haatveit - One of the best experts on this subject based on the ideXlab platform.
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dna vaccine expressing the non structural proteins of piscine Orthoreovirus delay the kinetics of prv infection and induces moderate protection against heart and skeletal muscle inflammation in atlantic salmon salmo salar
Vaccine, 2018Co-Authors: Hanne Merethe Haatveit, Ingvild Berg Nyman, Maria K. Dahle, Kjartan Hodneland, Stine Braaen, Elisabeth F Hansen, Petter Frost, Espen RimstadAbstract:Abstract Piscine Orthoreovirus (PRV) causes heart- and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). Erythrocytes are the main target cells for PRV. HSMI causes significant economic losses to the salmon aquaculture industry, and there is currently no vaccine available. PRV replicates and assembles within cytoplasmic structures called viral factories, mainly organized by the non-structural viral protein µNS. In two experimental vaccination trials in Atlantic salmon, using DNA vaccines expressing different combinations of PRV proteins, we found that expression of the non-structural proteins µNS combined with the cell attachment protein σ1 was associated with an increasing trend in lymphocyte marker gene expression in spleen, and induced moderate protective effect against HSMI.
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The non-structural protein μNS of piscine Orthoreovirus (PRV) forms viral factory-like structures
Veterinary Research, 2016Co-Authors: Hanne Merethe Haatveit, Maria Krudtaa Dahle, Turhan Markussen, Ingvild B. Nyman, Øystein Wessel, Espen RimstadAbstract:AbstractPiscine Orthoreovirus (PRV) is associated with heart- and skeletal muscle inflammation in farmed Atlantic salmon. The virus is ubiquitous and found in both farmed and wild salmonid fish. It belongs to the family Reoviridae, closely related to the genus Orthoreovirus. The PRV genome comprises ten double-stranded RNA segments encoding at least eight structural and two non-structural proteins. Erythrocytes are the major target cells for PRV. Infected erythrocytes contain globular inclusions resembling viral factories; the putative site of viral replication. For the mammalian reovirus (MRV), the non-structural protein μNS is the primary organizer in factory formation. The analogous PRV protein was the focus of the present study. The subcellular location of PRV μNS and its co-localization with the PRV σNS, µ2 and λ1 proteins was investigated. We demonstrated that PRV μNS forms dense globular cytoplasmic inclusions in transfected fish cells, resembling the viral factories of MRV. In co-transfection experiments with μNS, the σNS, μ2 and λ1 proteins were recruited to the globular structures. The ability of μNS to recruit other PRV proteins into globular inclusions indicates that it is the main viral protein involved in viral factory formation and pivotal in early steps of viral assembly.
Lin-fa Wang - One of the best experts on this subject based on the ideXlab platform.
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serological evidence of human infection by bat Orthoreovirus in singapore
Journal of Medical Virology, 2019Co-Authors: Anna Uehara, Kaw Bing Chua, Chee Wah Tan, Shailendra Mani, Yee Sin Leo, Danielle E Anderson, Lin-fa WangAbstract:To determine whether Pteropine Orthoreovirus (PRV) exposure has occurred in Singapore, we tested 856 individuals from an existing serum panel collected from 2005-2013. After an initial screen with luciferase immunoprecipitation system and secondary confirmation with virus neutralization test, we identified at least seven individuals with specific antibodies against PRV in both assays. Our findings confirm that PRV spillover into human populations is relatively common in this region of the world.
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Phylogenetic trees based on the nucleotide sequence of the four S-class genome segments of Orthoreoviruses.
2013Co-Authors: Kaw Bing Chua, Kenny Voon, Canady Keniscope, Kasri Abdul Rasid, Lin-fa WangAbstract:Abbreviations: ARV, Avian Orthoreovirus; BRV, baboon Orthoreovirus; DRV, Muscovy duck reovirus; MRV; Mammalian Orthoreovirus. See Table 1 for the abbreviations of all seven Pteropine Orthoreovirus strains known to date. The percentage of replicate trees in the bootstrap test (1000 replicates) is shown next to the branching node.
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broome virus a new fusogenic Orthoreovirus species isolated from an australian fruit bat
Virology, 2010Co-Authors: Claudia M Thalmann, Lin-fa Wang, David M Cummins, Ross A Lunt, L I Pritchard, Eric Hansson, Sandra Crameri, Alex D HyattAbstract:This report describes the discovery and characterization of a new fusogenic Orthoreovirus, Broome virus (BroV), isolated from a little red flying-fox (Pteropus scapulatus). The BroV genome consists of 10 dsRNA segments, each having a 3' terminal pentanucleotide sequence conserved amongst all members of the genus Orthoreovirus, and a unique 5' terminal pentanucleotide sequence. The smallest genome segment is bicistronic and encodes two small nonstructural proteins, one of which is a novel fusion associated small transmembrane (FAST) protein responsible for syncytium formation, but no cell attachment protein. The low amino acid sequence identity between BroV proteins and those of other Orthoreoviruses (13-50%), combined with phylogenetic analyses of structural and nonstructural proteins provide evidence to support the classification of BroV in a new sixth species group within the genus Orthoreovirus.
Ingvild Berg Nyman - One of the best experts on this subject based on the ideXlab platform.
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dna vaccine expressing the non structural proteins of piscine Orthoreovirus delay the kinetics of prv infection and induces moderate protection against heart and skeletal muscle inflammation in atlantic salmon salmo salar
Vaccine, 2018Co-Authors: Hanne Merethe Haatveit, Ingvild Berg Nyman, Maria K. Dahle, Kjartan Hodneland, Stine Braaen, Elisabeth F Hansen, Petter Frost, Espen RimstadAbstract:Abstract Piscine Orthoreovirus (PRV) causes heart- and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). Erythrocytes are the main target cells for PRV. HSMI causes significant economic losses to the salmon aquaculture industry, and there is currently no vaccine available. PRV replicates and assembles within cytoplasmic structures called viral factories, mainly organized by the non-structural viral protein µNS. In two experimental vaccination trials in Atlantic salmon, using DNA vaccines expressing different combinations of PRV proteins, we found that expression of the non-structural proteins µNS combined with the cell attachment protein σ1 was associated with an increasing trend in lymphocyte marker gene expression in spleen, and induced moderate protective effect against HSMI.
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Piscine Orthoreovirus (PRV) infects Atlantic salmon erythrocytes
Veterinary Research, 2014Co-Authors: Øystein Wessel Finstad, Maria Krudtaa Dahle, Tone Hæg Lindholm, Ingvild Berg Nyman, Marie Løvoll, Christian Wallace, Christel Moræus Olsen, Anne K Storset, Espen RimstadAbstract:Piscine Orthoreovirus (PRV) belongs to the Reoviridae family and is the only known fish virus related to the Orthoreovirus genus. The virus is the causative agent of heart and skeletal muscle inflammation (HSMI), an emerging disease in farmed Atlantic salmon (Salmo salar L.). PRV is ubiquitous in farmed Atlantic salmon and high loads of PRV in the heart are consistent findings in HSMI. The mechanism by which PRV infection causes disease remains largely unknown. In this study we investigated the presence of PRV in blood and erythrocytes using an experimental cohabitation challenge model. We found that in the early phases of infection, the PRV loads in blood were significantly higher than in any other organ. Most virus was found in the erythrocyte fraction, and in individual fish more than 50% of erythrocytes were PRV-positive, as determined by flow cytometry. PRV was condensed into large cytoplasmic inclusions resembling viral factories, as demonstrated by immunofluorescence and confocal microscopy. By electron microscopy we showed that these inclusions contained reovirus-like particles. The PRV particles and inclusions also had a striking resemblance to previously reported viral inclusions described as Erythrocytic inclusion body syndrome (EIBS). We conclude that the erythrocyte is a major target cell for PRV infection. These findings provide new information about HSMI pathogenesis, and show that PRV is an important factor of viral erythrocytic inclusions.
