Molecular chaperone TRiC governs avian reovirus replication by protecting outer-capsid protein σC and inner core protein σA and non-structural protein σNS from ubiquitin- proteasome degradation

2021 ◽  
pp. 109277
Author(s):  
Wei-Ru Huang ◽  
Jyun-Yi Li ◽  
Tsai-Ling Liao ◽  
Chuan-Ming Yeh ◽  
Chi-Young Wang ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Molecular Chaperone ◽  
Inner Core ◽  
Core Protein ◽  
Avian Reovirus ◽  
Structural Protein ◽  
Outer Capsid Protein ◽  
Ubiquitin Proteasome ◽  
Reovirus Replication ◽  
Outer Capsid

scholarly journals Structural Protein VP2 of African Horse Sickness Virus Is Not Essential for Virus Replication In Vitro

2016 ◽  
Vol 91 (4) ◽  
Author(s):  
René G. P. van Gennip ◽  
Sandra G. P. van de Water ◽  
Christiaan A. Potgieter ◽  
Piet A. van Rijn
Keyword(s):  
Capsid Protein ◽  
Virus Replication ◽  
Hemorrhagic Disease ◽  
African Horse Sickness ◽  
Structural Protein ◽  
Outer Capsid Protein ◽  
African Horse Sickness Virus ◽  
Content Type ◽  
Outer Capsid

ABSTRACT The Reoviridae family consists of nonenveloped multilayered viruses with a double-stranded RNA genome consisting of 9 to 12 genome segments. The Orbivirus genus of the Reoviridae family contains African horse sickness virus (AHSV), bluetongue virus, and epizootic hemorrhagic disease virus, which cause notifiable diseases and are spread by biting Culicoides species. Here, we used reverse genetics for AHSV to study the role of outer capsid protein VP2, encoded by genome segment 2 (Seg-2). Expansion of a previously found deletion in Seg-2 indicates that structural protein VP2 of AHSV is not essential for virus replication in vitro. In addition, in-frame replacement of RNA sequences in Seg-2 by that of green fluorescence protein (GFP) resulted in AHSV expressing GFP, which further confirmed that VP2 is not essential for virus replication. In contrast to virus replication without VP2 expression in mammalian cells, virus replication in insect cells was strongly reduced, and virus release from insect cells was completely abolished. Further, the other outer capsid protein, VP5, was not copurified with virions for virus mutants without VP2 expression. AHSV without VP5 expression, however, could not be recovered, indicating that outer capsid protein VP5 is essential for virus replication in vitro. Our results demonstrate for the first time that a structural viral protein is not essential for orbivirus replication in vitro, which opens new possibilities for research on other members of the Reoviridae family. IMPORTANCE Members of the Reoviridae family cause major health problems worldwide, ranging from lethal diarrhea caused by rotavirus in humans to economic losses in livestock production caused by different orbiviruses. The Orbivirus genus contains many virus species, of which bluetongue virus, epizootic hemorrhagic disease virus, and African horse sickness virus (AHSV) cause notifiable diseases according to the World Organization of Animal Health. Recently, it has been shown that nonstructural proteins NS3/NS3a and NS4 are not essential for virus replication in vitro, whereas it is generally assumed that structural proteins VP1 to -7 of these nonenveloped, architecturally complex virus particles are essential. Here we demonstrate for the first time that structural protein VP2 of AHSV is not essential for virus replication in vitro. Our findings are very important for virologists working in the field of nonenveloped viruses, in particular reoviruses.

MODELACIÓN POR COMPARACIÓN Y ACOPLAMIENTO MULTIMÉRICO DE LA PROTEÍNA EXTERIOR PEQUEÑA DE LA CÁPSIDE DEL BACTERIÓFAGO IME08

2020 ◽  
Vol 5 ◽  
Author(s):  
Maicol Ospina-Bedolla
Keyword(s):  
Capsid Protein ◽  
Protein Docking ◽  
Suitable Model ◽  
Structural Protein ◽  
Ramachandran Plot ◽  
Outer Capsid Protein ◽  
Structure Reliability ◽  
Model Platform ◽  
Outer Capsid

The small outer capsid protein plays a stabilizing role in the viral assembly, adhering to the<br />capsid during the later stages of maturation. This protein acts as glue among adjacent<br />capsomers, protecting the virus against extreme changes. The small outer capsid protein of the<br />bacteriophage IME08 was modelled using structural protein homology. A trimeric protein<br />docking was developed with the best-scored model and important sites of the molecules<br />interfaces were identified. It was used the Swiss Model platform for developing the protein<br />structure. Reliability was assessed by the QMEAN, Verify3D and ERRAT indices. The quality of<br />the whole model was verified by Ramachandran plot and the trimerization model was<br />performed on the platform ClusPro 2.0 Protein-Protein Docking. The structure obtained has a<br />reliability estimator QMEANscore4 of 0.769, rating it as a suitable model. The Z-Score QMEAN<br />value was 0.133, showing that the obtained model is not different from the experimental<br />structures stored in PDB database. The estimators and the Ramachandran plot evaluated<br />positively the model. Finally we identified a loop between two secondary structures as an<br />important site of the interaction of small outer capsid proteins, indicating that from residues 35<br />to 41 are relevant in the trimerization process.

scholarly journals Avian Reovirus Major μ-Class Outer Capsid Protein Influences Efficiency of Productive Macrophage Infection in a Virus Strain-Specific Manner

2001 ◽  
Vol 75 (11) ◽  
pp. 5027-5035 ◽  
Author(s):  
David O'Hara ◽  
Megan Patrick ◽  
Denisa Cepica ◽  
Kevin M. Coombs ◽  
Roy Duncan
Keyword(s):  
Capsid Protein ◽  
Genome Segment ◽  
Replication Cycle ◽  
Productive Infection ◽  
Avian Reovirus ◽  
Outer Capsid Protein ◽  
Macrophage Infection ◽  
Highly Pathogenic ◽  
Virus Replication Cycle ◽  
Outer Capsid

ABSTRACT We determined that the highly pathogenic avian reovirus strain 176 (ARV-176) possesses an enhanced ability to establish productive infections in HD-11 avian macrophages compared to avian fibroblasts. Conversely, the weakly pathogenic strain ARV-138 shows no such macrophagotropic tendency. The macrophage infection capability of the two viruses did not reflect differences in the ability to either induce or inhibit nitric oxide production. Moderate increases in the ARV-138 multiplicity of infection resulted in a concomitant increase in macrophage infection, and under such conditions the kinetics and extent of the ARV-138 replication cycle were equivalent to those of the highly infectious ARV-176 strain. These results indicated that both viruses are apparently equally capable of replicating in an infected macrophage, but they differ in the ability to establish productive infections in these cells. Using a genetic reassortant approach, we determined that the macrophagotropic property of ARV-176 reflects a post-receptor-binding step in the virus replication cycle and that the ARV-176 M2 genome segment is required for efficient infection of HD-11 cells. The M2 genome segment encodes the major μ-class outer capsid protein (μB) of the virus, which is involved in virus entry and transcriptase activation, suggesting that a host-specific influence on ARV entry and/or uncoating may affect the likelihood of the virus establishing a productive infection in a macrophage cell.

Development and efficacy of a grass carp reovirus (GCRV) outer capsid protein VP7 subunit vaccine

2012 ◽  
Vol 37 (6) ◽  
pp. 659-664 ◽  
Author(s):  
Shi-ying XU ◽  
Jing-hui LI ◽  
Yong ZOU ◽  
Lin LIU ◽  
Cheng-liang GONG ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Grass Carp ◽  
Subunit Vaccine ◽  
Outer Capsid Protein ◽  
Grass Carp Reovirus ◽  
Outer Capsid

scholarly journals Structure of the Three N-Terminal Immunoglobulin Domains of the Highly Immunogenic Outer Capsid Protein from a T4-Like Bacteriophage

2011 ◽  
Vol 85 (16) ◽  
pp. 8141-8148 ◽  
Author(s):  
A. Fokine ◽  
M. Z. Islam ◽  
Z. Zhang ◽  
V. D. Bowman ◽  
V. B. Rao ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Outer Capsid Protein ◽  
Outer Capsid

scholarly journals Cryo-EM structure of the bacteriophage T4 isometric head at 3.3-Å resolution and its relevance to the assembly of icosahedral viruses

2017 ◽  
Vol 114 (39) ◽  
pp. E8184-E8193 ◽  
Author(s):  
Zhenguo Chen ◽  
Lei Sun ◽  
Zhihong Zhang ◽  
Andrei Fokine ◽  
Victor Padilla-Sanchez ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Major Capsid Protein ◽  
Bacteriophage T4 ◽  
Hexagonal Lattice ◽  
Scaffolding Proteins ◽  
Outer Capsid Protein ◽  
Head Assembly ◽  
Icosahedral Viruses ◽  
End Caps ◽  
Outer Capsid

The 3.3-Å cryo-EM structure of the 860-Å-diameter isometric mutant bacteriophage T4 capsid has been determined. WT T4 has a prolate capsid characterized by triangulation numbers (T numbers) Tend= 13 for end caps and Tmid= 20 for midsection. A mutation in the major capsid protein, gp23, produced T=13 icosahedral capsids. The capsid is stabilized by 660 copies of the outer capsid protein, Soc, which clamp adjacent gp23 hexamers. The occupancies of Soc molecules are proportional to the size of the angle between the planes of adjacent hexameric capsomers. The angle between adjacent hexameric capsomers is greatest around the fivefold vertices, where there is the largest deviation from a planar hexagonal array. Thus, the Soc molecules reinforce the structure where there is the greatest strain in the gp23 hexagonal lattice. Mutations that change the angles between adjacent capsomers affect the positions of the pentameric vertices, resulting in different triangulation numbers in bacteriophage T4. The analysis of the T4 mutant head assembly gives guidance to how other icosahedral viruses reproducibly assemble into capsids with a predetermined T number, although the influence of scaffolding proteins is also important.

scholarly journals Putative Autocleavage of Outer Capsid Protein μ1, Allowing Release of Myristoylated Peptide μ1N during Particle Uncoating, Is Critical for Cell Entry by Reovirus

2004 ◽  
Vol 78 (16) ◽  
pp. 8732-8745 ◽  
Author(s):  
Amy L. Odegard ◽  
Kartik Chandran ◽  
Xing Zhang ◽  
John S. L. Parker ◽  
Timothy S. Baker ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Structural Changes ◽  
General Mechanism ◽  
Membrane Penetration ◽  
Outer Capsid Protein ◽  
Core Proteins ◽  
Peptide Release ◽  
Outer Capsid

ABSTRACT Several nonenveloped animal viruses possess an autolytic capsid protein that is cleaved as a maturation step during assembly to yield infectious virions. The 76-kDa major outer capsid protein μ1 of mammalian orthoreoviruses (reoviruses) is also thought to be autocatalytically cleaved, yielding the virion-associated fragments μ1N (4 kDa; myristoylated) and μ1C (72 kDa). In this study, we found that μ1 cleavage to yield μ1N and μ1C was not required for outer capsid assembly but contributed greatly to the infectivity of the assembled particles. Recoated particles containing mutant, cleavage-defective μ1 (asparagine → alanine substitution at amino acid 42) were competent for attachment; processing by exogenous proteases; structural changes in the outer capsid, including μ1 conformational change and σ1 release; and transcriptase activation but failed to mediate membrane permeabilization either in vitro (no hemolysis) or in vivo (no coentry of the ribonucleotoxin α-sarcin). In addition, after these particles were allowed to enter cells, the δ region of μ1 continued to colocalize with viral core proteins in punctate structures, indicating that both elements remained bound together in particles and/or trapped within the same subcellular compartments, consistent with a defect in membrane penetration. If membrane penetration activity was supplied in trans by a coinfecting genome-deficient particle, the recoated particles with cleavage-defective μ1 displayed much higher levels of infectivity. These findings led us to propose a new uncoating intermediate, at which particles are trapped in the absence of μ1N/μ1C cleavage. We additionally showed that this cleavage allowed the myristoylated, N-terminal μ1N fragment to be released from reovirus particles during entry-related uncoating, analogous to the myristoylated, N-terminal VP4 fragment of picornavirus capsid proteins. The results thus suggest that hydrophobic peptide release following capsid protein autocleavage is part of a general mechanism of membrane penetration shared by several diverse nonenveloped animal viruses.

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