The sequence and phylogenetic analysis of avian reovirus genome segments M1, M2, and M3 encoding the minor core protein μA, the major outer capsid protein μB, and the nonstructural protein μNS

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.

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Genetic and phylogenetic analysis of the outer capsid protein genes of Indian isolates of bluetongue virus serotype-16

Veterinary World ◽

10.14202/vetworld.2018.1025-1029 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1025-1029 ◽

Cited By ~ 1

Author(s):

Arpit Saxena ◽

Sanchay K. Biswas ◽

Karam Chand ◽

Jishnu Naskar ◽

Ankita Chauhan ◽

...

Keyword(s):

Phylogenetic Analysis ◽

Capsid Protein ◽

Bluetongue Virus ◽

Outer Capsid Protein ◽

Virus Serotype ◽

Indian Isolates ◽

Outer Capsid

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

JOURNAL OF HUNAN AGRICULTURAL UNIVERSITY ◽

10.3724/sp.j.1238.2011.00659 ◽

2012 ◽

Vol 37 (6) ◽

pp. 659-664 ◽

Cited By ~ 1

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

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

Journal of Virology ◽

10.1128/jvi.00847-11 ◽

2011 ◽

Vol 85 (16) ◽

pp. 8141-8148 ◽

Cited By ~ 39

Author(s):

A. Fokine ◽

M. Z. Islam ◽

Z. Zhang ◽

V. D. Bowman ◽

V. B. Rao ◽

...

Keyword(s):

Capsid Protein ◽

Outer Capsid Protein ◽

Outer Capsid

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1708483114 ◽

2017 ◽

Vol 114 (39) ◽

pp. E8184-E8193 ◽

Cited By ~ 34

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.

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

Journal of Virology ◽

10.1128/jvi.78.16.8732-8745.2004 ◽

2004 ◽

Vol 78 (16) ◽

pp. 8732-8745 ◽

Cited By ~ 96

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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Infection immunity of piglets to either VP3 or VP7 outer capsid protein confers resistance to challenge with a virulent rotavirus bearing the corresponding antigen.

Journal of Virology ◽

10.1128/jvi.62.3.744-748.1988 ◽

1988 ◽

Vol 62 (3) ◽

pp. 744-748 ◽

Cited By ~ 73

Author(s):

Y Hoshino ◽

L J Saif ◽

M M Sereno ◽

R M Chanock ◽

A Z Kapikian

Keyword(s):

Capsid Protein ◽

Outer Capsid Protein ◽

Outer Capsid

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Cell Entry-Independent Role for the Reovirus μ1 Protein in Regulating Necroptosis and the Accumulation of Viral Gene Products

Journal of Virology ◽

10.1128/jvi.00199-19 ◽

2019 ◽

Vol 93 (11) ◽

Cited By ~ 5

Author(s):

Katherine E. Roebke ◽

Pranav Danthi

Keyword(s):

Cell Death ◽

Capsid Protein ◽

Apoptotic Cell ◽

Guanidine Hydrochloride ◽

Viral Gene ◽

Gene Products ◽

Minus Strand ◽

Outer Capsid Protein ◽

Infected Cells ◽

Outer Capsid

ABSTRACTThe reovirus outer capsid protein μ1 regulates cell death in infected cells. To distinguish between the roles of incoming, capsid-associated, and newly synthesized μ1, we used small interfering RNA (siRNA)-mediated knockdown. Loss of newly synthesized μ1 protein does not affect apoptotic cell death in HeLa cells but enhances necroptosis in L929 cells. Knockdown of μ1 also affects aspects of viral replication. We found that, while μ1 knockdown results in diminished release of infectious viral progeny from infected cells, viral minus-strand RNA, plus-strand RNA, and proteins that are not targeted by the μ1 siRNA accumulate to a greater extent than in control siRNA-treated cells. Furthermore, we observed a decrease in sensitivity of these viral products to inhibition by guanidine hydrochloride (GuHCl) (which targets minus-strand synthesis to produce double-stranded RNA) when μ1 is knocked down. Following μ1 knockdown, cell death is also less sensitive to treatment with GuHCl. Our studies suggest that the absence of μ1 allows enhanced transcriptional activity of newly synthesized cores and the consequent accumulation of viral gene products. We speculate that enhanced accumulation and detection of these gene products due to μ1 knockdown potentiates receptor-interacting protein 3 (RIP3)-dependent cell death.IMPORTANCEWe used mammalian reovirus as a model to study how virus infections result in cell death. Here, we sought to determine how viral factors regulate cell death. Our work highlights a previously unknown role for the reovirus outer capsid protein μ1 in limiting the induction of a necrotic form of cell death called necroptosis. Induction of cell death by necroptosis requires the detection of viral gene products late in infection; μ1 limits cell death by this mechanism because it prevents excessive accumulation of viral gene products that trigger cell death.

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