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Qin Fang - One of the best experts on this subject based on the ideXlab platform.

  • Aquareovirus an overview
    2021
    Co-Authors: Qin Fang, Jie Zhang, Fuxian Zhang
    Abstract:

    Viruses in the family Reoviridae can infect a wide range of hosts, including humans, vertebrates, invertebrates, fungi, bacteria, and plants. They form a diverse group, harboring particular 9–12 segmented double-stranded RNA genomes contained within icosahedral, nonenveloped, multilayered protein capsids. Aquareovirus, a recently classified member of the Reoviridae family, has been isolated from aquatic animals of freshwater and saline water origins worldwide. Generally, Aquareoviruses exert low pathogenicity in their natural hosts. However, some isolates are highly virulent in cultured fish species. Aquareovirus particles physically resemble orthoreoviruses, and the enclosed 11-segmented genome is similar to that of rotaviruses; however, no antigenic relationship has been detected. An increasing number of genome sequence- and particle structure-based evolutionary analyses suggest that the genus Aquareovirus shares a sister-like relationship with members of the genus Orthoreovirus. This new molecular evidence indicates that the peculiar endogenous transcription and cell penetration-related characteristics are attributed to uniformly conserved protein and functional domains encoded by the genome segments 1–6 (S1–S6) of Aquareoviruses. In contrast, proteins encoded by smaller class gene segments (S7–S11) that are involved in cell-receptor attachment and replication-related events are largely divergent. Therefore, our current understanding of Aquareovirus infection and pathogenesis provides significant insights into the fundamental mechanisms involved in the molecular evolution of the 11 genomic segments and, in general, functions of the encoded proteins, thereby leading to the development of better prevention and control strategies for diseases caused by Aquareovirus infection.

  • the Aquareovirus particle structure and protein functions
    2021
    Co-Authors: Qin Fang, Fuxian Zhang, Jie Zhang
    Abstract:

    Aquareoviruses and orthoreoviruses belong to two different genera in the Spinareovirinae group of the family Reoviridae, but they share many common features in genome evolution, replication, and particle assembly. Using three-dimensional image reconstruction and cryo-electron microscopy, a mass of structural information of the Aquareovirus particles has been revealed. Each Aquareovirus particle contains 11 double-stranded RNA (dsRNA) genomic segments enclosed by multilayered proteinaceous shells: the inner and outer shells comprising seven structural proteins (VP1–VP7). The inner core particle is composed of five proteins: VP1, VP2, VP3, VP4, and VP6. The inner core shell is formed by two conformers of VP3 (VP3A and VP3B), which are clamped by equivalent molecules of VP6 (VP6A and VP6B, respectively). A distinct pentameric turret structure formed by five copies of the protein VP1 sits around the 12 fivefold axes crossing over the inner and outer shell. The RNA polymerase protein VP2 and co-factor protein VP4 are anchored to the inner surface near the fivefold axis and found to directly interact with the genomic dsRNA and VP3. The outer shell of the viral particle comprises 200 trimers of VP5–VP7 heterodimers. These seven structural proteins of the Aquareovirus are closely related to the proteins λ1, λ2, λ3, μ1, μ2, μ3, and σ3 of the mammalian orthoreovirus (MRV) in the overall protein structure and functional domains. An obvious difference is that the Aquareovirus lacks σ1 protein situated on each fivefold vertex, which functions as the cell attachment protein in the MRV. This chapter describes the Aquareovirus particle structure and protein functions.

  • endosomes and microtubles are required for productive infection in Aquareovirus
    Virologica Sinica, 2020
    Co-Authors: Fuxian Zhang, Qingxiu Chen, Hong Guo, Zheng Ruan, Qin Fang
    Abstract:

    Grass carp reovirus (GCRV), the genus Aquareovirus in family Reoviridae, is viewed as the most pathogenic Aquareovirus. To understand the molecular mechanism of how Aquareovirus initiates productive infection, the roles of endosome and microtubule in cell entry of GCRV are investigated by using quantum dots (QDs)-tracking in combination with biochemical approaches. We found that GCRV infection and viral protein synthesis were significantly inhibited by pretreating host cells with endosome acidification inhibitors NH4Cl, chloroquine and bafilomycin A1 (Bafi). Confocal images indicated that GCRV particles could colocalize with Rab5, Rab7 and lysosomes in host cells. Further ultrastructural examination validated that viral particle was found in late endosomes. Moreover, disruption of microtubules with nocodazole clearly blocked GCRV entry, while no inhibitory effects were observed with cytochalasin D treated cells in viral infection, hinting that intracellular transportation of endocytic uptake in GCRV infected cells is via microtubules but not actin filament. Notably, viral particles were observed to transport along microtubules by using QD-labeled GCRV. Altogether, our results suggest that GCRV can use endosomes and microtubules to initiate productive infection.

  • structure of rna polymerase complex and genome within a dsrna virus provides insights into the mechanisms of transcription and assembly
    Proceedings of the National Academy of Sciences of the United States of America, 2018
    Co-Authors: Xurong Wang, Qin Fang, Fuxian Zhang, Wenyuan Chen, Qingxiu Chen, Tao Yang, Jiawei Wang, Hongrong Liu, Lingpeng Cheng
    Abstract:

    Most double-stranded RNA (dsRNA) viruses transcribe RNA plus strands within a common innermost capsid shell. This process requires coordinated efforts by RNA-dependent RNA polymerase (RdRp) together with other capsid proteins and genomic RNA. Here we report the near-atomic resolution structure of the RdRp protein VP2 in complex with its cofactor protein VP4 and genomic RNA within an Aquareovirus capsid using 200-kV cryoelectron microscopy and symmetry-mismatch reconstruction. The structure of these capsid proteins enabled us to observe the elaborate nonicosahedral structure within the double-layered icosahedral capsid. Our structure shows that the RdRp complex is anchored at the inner surface of the capsid shell and interacts with genomic dsRNA and four of the five asymmetrically arranged N termini of the capsid shell proteins under the fivefold axis, implying roles for these N termini in virus assembly. The binding site of the RNA end at VP2 is different from the RNA cap binding site identified in the crystal structure of orthoreovirus RdRp λ3, although the structures of VP2 and λ3 are almost identical. A loop, which was thought to separate the RNA template and transcript, interacts with an apical domain of the capsid shell protein, suggesting a mechanism for regulating RdRp replication and transcription. A conserved nucleoside triphosphate binding site was localized in our RdRp cofactor protein VP4 structure, and interactions between the VP4 and the genomic RNA were identified.

  • identification of the caveolae raft mediated endocytosis as the primary entry pathway for Aquareovirus
    Virology, 2018
    Co-Authors: Fuxian Zhang, Qingxiu Chen, Jie Zhang, Hong Guo, Qin Fang
    Abstract:

    Grass carp reovirus (GCRV), a member of the Aquareovirus genus in the Reoviridae family, is considered the most pathogenic Aquareovirus. However, its productive viral entry pathways remain largely unclear. Using a combination of quantum dot (QD)-based live-virus tracking and biochemical assays, we found that extraction of cellular membrane cholesterol with methyl-β-cyclodextrin (MβCD) and nystatin strongly inhibited the internalization of GCRVs, and supplementation with cholesterol restored viral infection. In addition, the entry of the virus was restrained by genistein, an inhibitor known to block caveolar endocytosis. Subsequent real-time tracking experiments revealed that the QD-labeled GCRV particles were colocalized with caveolin-1, and transfection of cells with dominant-negative mutant (caveolin-1 Y14F) significantly reduced GCRV infection. In contrast, no effects on virus infection were detected when the clathrin-mediated endocytosis or the macropinocytosis inhibitors were used. Our results collectively suggest that Aquareoviruses can use caveolae/raft-mediated endocytosis as the primary entry pathway to initiate productive infection.

Siba K. Samal - One of the best experts on this subject based on the ideXlab platform.

  • trypsin induced structural transformation in Aquareovirus
    Journal of Virology, 2000
    Co-Authors: Emma L Nason, Siba K. Samal, B Venkataram V Prasad
    Abstract:

    Aquareovirus, a member of the family Reoviridae, is a large virus with multiple capsid layers surrounding a genome composed of 11 segments of double-stranded RNA. Biochemical studies have shown that treatment with the proteolytic agent trypsin significantly alters the infectivity of the virus. The most infectious stage of the virus is produced by a 5-min treatment with trypsin. However, prolonged trypsin treatment almost completely abolishes the infectivity. We have used three-dimensional electron cryomicroscopy to gain insight into the structural basis of protease-induced alterations in infectivity by examining the structural changes in the virion at various time intervals of trypsin treatment. Our data show that after 5 min of trypsinization, projection-like spikes made of VP7 (35 kDa), associated with the underlying trimeric subunits, are completely removed. Concurrent with the removal of VP7, conformational changes are observed in the trimeric subunit composed of putative VP5 (71 kDa). The removal of VP7 and the accompanied structural changes may expose regions in the putative VP5 important for cell entry processes. Prolonged trypsinization not only entirely removes the outer capsid layer, producing the poorly infectious core particle, but also causes significant conformational changes in the turret protein. These changes result in shortening of the turret and narrowing of its central channel. The turret, as in orthoreoviruses, is likely to play a major role in the capping and translocation of mRNA during transcription, and the observed conformational flexibility in the turret protein may have implications in rendering the particle transcriptionally active or inactive.

  • Trypsin-induced structural transformation in Aquareovirus
    2000
    Co-Authors: Emma Nason, Siba K. Samal, Emma L Nason, Bidadi V Prasad, Available Bidadi, V Prasad, B Venkataram V Prasad
    Abstract:

    Aquareovirus, a member of the family Reoviridae, is a large virus with multiple capsid layers surrounding a genome composed of 11 segments of double-stranded RNA. Biochemical studies have shown that treatment with the proteolytic agent trypsin significantly alters the infectivity of the virus. The most infectious stage of the virus is produced by a 5-min treatment with trypsin. However, prolonged trypsin treatment almost completely abolishes the infectivity. We have used three-dimensional electron cryomicroscopy to gain insight into the structural basis of protease-induced alterations in infectivity by examining the structural changes in the virion at various time intervals of trypsin treatment. Our data show that after 5 min of trypsinization, projection-like spikes made of VP7 (35 kDa), associated with the underlying trimeric subunits, are completely removed. Concurrent with the removal of VP7, conformational changes are observed in the trimeric subunit composed of putative VP5 (71 kDa). The removal of VP7 and the accompanied structural changes may expose regions in the putative VP5 important for cell entry processes. Prolonged trypsinization not only entirely removes the outer capsid layer, producing the poorly infectious core particle, but also causes significan

  • identification of grass carp haemorrhage virus as a new genogroup of Aquareovirus
    Journal of General Virology, 1999
    Co-Authors: Aymara A C Rangel, Daniel D Rockemann, F M Hetrick, Siba K. Samal
    Abstract:

    Three Aquareovirus strains isolated from grass carp (Ctenopharyngodon idellus), geoduck clams (Panope abrupta) and herring (Clupea harengus) in North America and Asia were examined by RNA–RNA blot hybridization to determine their genogroup. The isolates from clams and herring were identified as members of genogroup A, but the isolate from grass carp did not hybridize to any of the known genogroups, suggesting that this virus probably represents a new, seventh genogroup.

  • Identification of grass carp haemorrhage virus as a new genogroup of Aquareovirus
    1999
    Co-Authors: Aymara A C Rangel, Frank M. Hetrick, Daniel D Rockemann, Siba K. Samal
    Abstract:

    Three Aquareovirus strains isolated from grass carp (Ctenopharyngodon idellus), geoduck clams (Pan-ope abrupta) and herring (Clupea harengus) in NorthAmerica andAsia wereexaminedby RNA–RNA blot hybridization to determine their genogroup. The isolates from clams and herring were identified as members of genogroup A, but the isolate from grass carp did not hybridize to any of the known genogroups, suggesting that this virus probably represents a new, seventh genogroup. Aquareoviruses have been isolated from a wide variety of aquatic animals, including finfish and crustacea, throughout the world (Lupiani et al., 1995). These viruses replicate in cell cultures of piscine and mammalian origins, at temperatures between 15 °C and 25 °C (Samal et al., 1998). They provide

  • Enhancement of Aquareovirus Infectivity by Treatment with Proteases: Mechanism of Action
    Journal of virology, 1998
    Co-Authors: Thomas H. Mcphillips, Kothandaraman Subramanian, David Dinan, Siba K. Samal
    Abstract:

    The effects of protease digestion on the polypeptide composition and on the infectivity of striped bass virus, an Aquareovirus, were examined. Both trypsin and chymotrypsin enhanced the infectivity of the virus. Enhancement of infectivity was correlated with the digestion of the outer capsid protein, VP7. These studies support the assertion that VP7 is the outermost capsid protein and suggest that VP4 and VP5 are exposed on the outer surface of infectious particles. The possible role of VP7 in the variation in virulence observed among Aquareovirus isolates is discussed.

Heidrun Plarre - One of the best experts on this subject based on the ideXlab platform.

  • Complete genome of Atlantic halibut reovirus (AHRV) associated with mortality in production of Atlantic halibut (Hippoglossus hippoglossus) fry
    Aquaculture, 2019
    Co-Authors: Renate Hvidsten Skoge, Are Nylund, Kjetil Solheim, Heidrun Plarre
    Abstract:

    Abstract The Aquareovirus (AQRV) member Atlantic halibut reovirus (AHRV) is associated with severe liver pathology and high fry mortality and constitutes a significant problem for Atlantic halibut (Hippoglossus hippoglossus) production in Norway. Halibut is a batch spawner and it has been suspected that AHRV may be transmitted via eggs since outbreaks of disease arise in successive batches of fry originating from the same group of brood fish. In this study, we present the complete genome of AHRV representing the first complete AQRV genome sequence from a marine cold-water fish species in the North Atlantic. The terminal 5′- and 3′-ends of the segments have the canonical conserved nucleotides 5′-GUUUUAU------UCAUC-3′. The 13 putative proteins encoded in the 11 AHRV genome segments share the highest amino acid identity with members of species AQRV A and B. Phylogenetic analysis of the most conserved proteins (VP1, VP2, VP3 and VP5) groups AHRV in a major clade together with the same two species. However, the differences in host and environment, and the amino acid sequence identity of the RdRp (~80%) compared to either AQRV A or B, suggest that this virus could possibly represent a novel species within the genus. Furthermore, we show that even though AHRV RNA cannot be detected by real time RT PCR in the first egg batches from asymptomatic Atlantic halibut brood fish, the viral RNA load is not only detectable, but appears to increase in successive spawning batches.

  • A new Aquareovirus causing high mortality in farmed Atlantic halibut fry in Norway
    Archives of Virology, 2015
    Co-Authors: Steffen Blindheim, Are Nylund, Heidrun Plarre, Børre Erstad, Kuninori Watanabe, Stian Nylund
    Abstract:

    A new Aquareovirus was isolated from cultured Atlantic halibut ( Hippoglossus hippoglossus ) fry at a facility where massive mortalities had occurred during the start-feeding phase. The same virus was also detected in juveniles (about 10 grams) of the 2013 generation at two other production sites, but not in larger fish from generations 2007–2012. The virus replicated in BF-2 and CHSE-214 cell cultures and produced syncytia and plaque-like cytopathic effects. This Atlantic halibut reovirus (AHRV) was associated with necrosis of the liver and pancreas, syncytium formation in these tissues, and distinct viroplasm areas within the syncytium in halibut fry. Transmission electron microscopy revealed that the viroplasm contained virions, non-enveloped, icosahedral particles approximately 70 nm in diameter with a double capsid layer, amorphous material, and tubular structures. The RNA-dependent RNA polymerase (RdRp) gene from the AHRV isolates showed the highest amino acid sequence identity (80 %) to an isolate belonging to the species Aquareovirus A , Atlantic salmon reovirus TS (ASRV-TS). A partial sequence from the putative fusion-associated small transmembrane (FAST) protein of AHRV was obtained, and this sequence showed the highest amino acid sequence identity (46.8 %) to Green River Chinook virus which is an unassigned member of the genus Aquareovirus , while a comparison with isolates belonging to the species Aquareovirus A showed

  • a new Aquareovirus causing high mortality in farmed atlantic halibut fry in norway
    Archives of Virology, 2015
    Co-Authors: Steffen Blindheim, Are Nylund, Heidrun Plarre, Børre Erstad, Kuninori Watanabe, Stian Nylund
    Abstract:

    A new Aquareovirus was isolated from cultured Atlantic halibut (Hippoglossus hippoglossus) fry at a facility where massive mortalities had occurred during the start-feeding phase. The same virus was also detected in juveniles (about 10 grams) of the 2013 generation at two other production sites, but not in larger fish from generations 2007–2012. The virus replicated in BF-2 and CHSE-214 cell cultures and produced syncytia and plaque-like cytopathic effects. This Atlantic halibut reovirus (AHRV) was associated with necrosis of the liver and pancreas, syncytium formation in these tissues, and distinct viroplasm areas within the syncytium in halibut fry. Transmission electron microscopy revealed that the viroplasm contained virions, non-enveloped, icosahedral particles approximately 70 nm in diameter with a double capsid layer, amorphous material, and tubular structures. The RNA-dependent RNA polymerase (RdRp) gene from the AHRV isolates showed the highest amino acid sequence identity (80 %) to an isolate belonging to the species Aquareovirus A, Atlantic salmon reovirus TS (ASRV-TS). A partial sequence from the putative fusion-associated small transmembrane (FAST) protein of AHRV was obtained, and this sequence showed the highest amino acid sequence identity (46.8 %) to Green River Chinook virus which is an unassigned member of the genus Aquareovirus, while a comparison with isolates belonging to the species Aquareovirus A showed <33 % identity. A proper assessment of the relationship of AHRV to all members of the genus Aquareovirus, however, is hampered by the absence of genetic data from members of several Aquareovirus species. AHRV is the first Aquareovirus isolated from a marine coldwater fish species and the second reovirus detected in farmed fish in Norway. A similar disease of halibut fry, as described in this paper, has also been described in halibut production facilities in Canada and Scotland.

Stian Nylund - One of the best experts on this subject based on the ideXlab platform.

  • A new Aquareovirus causing high mortality in farmed Atlantic halibut fry in Norway
    Archives of Virology, 2015
    Co-Authors: Steffen Blindheim, Are Nylund, Heidrun Plarre, Børre Erstad, Kuninori Watanabe, Stian Nylund
    Abstract:

    A new Aquareovirus was isolated from cultured Atlantic halibut ( Hippoglossus hippoglossus ) fry at a facility where massive mortalities had occurred during the start-feeding phase. The same virus was also detected in juveniles (about 10 grams) of the 2013 generation at two other production sites, but not in larger fish from generations 2007–2012. The virus replicated in BF-2 and CHSE-214 cell cultures and produced syncytia and plaque-like cytopathic effects. This Atlantic halibut reovirus (AHRV) was associated with necrosis of the liver and pancreas, syncytium formation in these tissues, and distinct viroplasm areas within the syncytium in halibut fry. Transmission electron microscopy revealed that the viroplasm contained virions, non-enveloped, icosahedral particles approximately 70 nm in diameter with a double capsid layer, amorphous material, and tubular structures. The RNA-dependent RNA polymerase (RdRp) gene from the AHRV isolates showed the highest amino acid sequence identity (80 %) to an isolate belonging to the species Aquareovirus A , Atlantic salmon reovirus TS (ASRV-TS). A partial sequence from the putative fusion-associated small transmembrane (FAST) protein of AHRV was obtained, and this sequence showed the highest amino acid sequence identity (46.8 %) to Green River Chinook virus which is an unassigned member of the genus Aquareovirus , while a comparison with isolates belonging to the species Aquareovirus A showed

  • a new Aquareovirus causing high mortality in farmed atlantic halibut fry in norway
    Archives of Virology, 2015
    Co-Authors: Steffen Blindheim, Are Nylund, Heidrun Plarre, Børre Erstad, Kuninori Watanabe, Stian Nylund
    Abstract:

    A new Aquareovirus was isolated from cultured Atlantic halibut (Hippoglossus hippoglossus) fry at a facility where massive mortalities had occurred during the start-feeding phase. The same virus was also detected in juveniles (about 10 grams) of the 2013 generation at two other production sites, but not in larger fish from generations 2007–2012. The virus replicated in BF-2 and CHSE-214 cell cultures and produced syncytia and plaque-like cytopathic effects. This Atlantic halibut reovirus (AHRV) was associated with necrosis of the liver and pancreas, syncytium formation in these tissues, and distinct viroplasm areas within the syncytium in halibut fry. Transmission electron microscopy revealed that the viroplasm contained virions, non-enveloped, icosahedral particles approximately 70 nm in diameter with a double capsid layer, amorphous material, and tubular structures. The RNA-dependent RNA polymerase (RdRp) gene from the AHRV isolates showed the highest amino acid sequence identity (80 %) to an isolate belonging to the species Aquareovirus A, Atlantic salmon reovirus TS (ASRV-TS). A partial sequence from the putative fusion-associated small transmembrane (FAST) protein of AHRV was obtained, and this sequence showed the highest amino acid sequence identity (46.8 %) to Green River Chinook virus which is an unassigned member of the genus Aquareovirus, while a comparison with isolates belonging to the species Aquareovirus A showed <33 % identity. A proper assessment of the relationship of AHRV to all members of the genus Aquareovirus, however, is hampered by the absence of genetic data from members of several Aquareovirus species. AHRV is the first Aquareovirus isolated from a marine coldwater fish species and the second reovirus detected in farmed fish in Norway. A similar disease of halibut fry, as described in this paper, has also been described in halibut production facilities in Canada and Scotland.

Zuoyan Zhu - One of the best experts on this subject based on the ideXlab platform.

  • the molecular characterization of rna segment s9 of grass carp hemorrhage virus gchv an Aquareovirus
    Aquaculture, 2001
    Co-Authors: Tao Qiu, Jian Zhang, Zuoyan Zhu
    Abstract:

    Although reovirus infection is one of the major virus diseases of grass carp in China, the available knowledge on the structure and function of genes and proteins of the virus is limited. The complete sequence of the S9 genome segment of grass carp hemorrhage virus (GCHV) was determined. The segment consists of 1130 nucleotides and has a large open reading frame (ORF) encoding a protein of 352 amino acids with predicted molecular mass of 37.7 kDa. Amino acid sequence comparison revealed that the deduced protein encoded by GCHV S9 is closely related to the sigma NS proteins of mammalian reovirus (MRV) and avian reovirus (ARV). Secondary structure analysis displayed that the form of alpha -helices (40.1%) and beta -sheets (49.4%) are the richest two contents in the protein encoded by S9, and this protein is predicted to be a nonstructural protein. (C) 2001 Elsevier Science B.V. All rights reserved.

  • molecular characterization and expression of the m6 gene of grass carp hemorrhage virus gchv an Aquareovirus
    Archives of Virology, 2001
    Co-Authors: Tao Qiu, Jian Zhang, Zuoyan Zhu
    Abstract:

    The complete nucleotide sequence of M6 gene of grass carp hemorrhage virus (GCHV) was determined. It is 2039 nucleotides in length and contains a single large open reading frame that could encode a protein of 648 amino acids with predicted molecular mass of 68.7 kDa. Amino acid sequence comparison revealed that the protein encoded by GCHV M6 is closely related to the protein μl of mammalian reovirus. The M6 gene, encoding the major outer-capsid protein, was expressed using the pET fusion protein vector in Escherichia coli and detected by Western blotting using chicken anti-GCHV immunoglobulin (IgY). The result indicates that the protein encoded by M6 may share a putative Asn-42-Pro-43 proteolytic cleavage site with μl.

  • sequence of genome segments 1 2 and 3 of the grass carp reovirus genus Aquareovirus family reoviridae
    Biochemical and Biophysical Research Communications, 2000
    Co-Authors: Qin Fang, Houssam Attoui, Philippe De Micco, Jean Francois Philippe Biagini, Zuoyan Zhu, Xavier De Lamballerie
    Abstract:

    The genome segments 1, 2, and 3 of the grass carp reovirus (GCRV), a tentative species assigned to genus Aquareouirus, family Reouiridae, were sequenced. The respective segments 1, 2, and 3 were 3949, 3877, and 3702 nucleotides long. Conserved moths 5' (GUUAUUU) and 3' (UUCAUC) were found at the ends of each segment. Each segment contains a single ORF and the negative strand does not permit identification of consistent ORFs. Sequence analysis revealed that VP2 is the viral polymerase, while VPI might represent the viral guanyly/methyl transferase (involved in the capping process of RNA transcripts) and VP3 the NTPase/helicase (involved in the transcription and capping of viral RNAs), The highest amino acid identities (26-41%) were found with orthoreovirus proteins. Further genomic characterization should provide insight about the genetic relationships between GCRV, Aquareoviruses, and orthoreoviruses, It should also permit to precise the taxonomic status of these different viruses. (C) 2000 Academic Press.