Background: Grass Carp Reovirus (GCRV), a highly virulent agent of aquatic animals, has an eleven segmented dsRNA genome encased in a multilayered capsid shell, which encodes twelve proteins including seven structural proteins (VP1-VP7), and five nonstructural proteins (NS80, NS38, NS31, NS26, and NS16). It has been suggested that the protein NS80 plays an important role in the viral replication cycle that is similar to that of its homologous protein μNS in the genus of Orthoreovirus.
Results: As a step to understanding the basis of the part played by NS80 in GCRV replication and particle assembly, we used the yeast two-hybrid (Y2H) system to identify NS80 interactions with proteins NS38, VP4, and VP6 as well as NS80 and NS38 self-interactions, while no interactions appeared in the four protein pairs NS38-VP4, NS38-VP6, VP4-VP4, and VP4-VP6. Bioinformatic analyses of NS80 with its corresponding proteins were performed with all currently available homologous protein sequences in ARVs (avian reoviruses) and MRVs (mammalian reoviruses) to predict further potential functional domains of NS80 that are related to VFLS (viral factory-like structures) formation and other roles in viral replication. Two conserved regions spanning from aa (amino acid) residues of 388 to 433, and 562 to 580 were discovered in this study. The second conserved region with corresponding conserved residues Tyr565, His569, Cys571, Asn573, and Glu576 located between the two coiled-coils regions (aa ~513-550 and aa ~615-690) in carboxyl-proximal terminus were supposed to be essential to form VFLS, so that aa residues ranging from 513 to 742 of NS80 was inferred to be the smallest region that is necessary for forming VFLS. The function of the first conserved region including Ala395, Gly419, Asp421, Pro422, Leu438, and Leu443 residues is unclear, but one-third of the amino-terminal region might be species specific, dominating interactions with other viral components.
Conclusions: Our results in this study together with those from previous investigations indicate the protein NS80 might play a central role in VFLS formation and viral components recruitment in GCRV particle assembly, similar to the μNS protein in ARVs and MRVs.
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http://dx.doi.org/10.1186/1743-422X-8-168 | DOI Listing |
J Virol
September 2024
State Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
Unlabelled: Grass carp reovirus (GCRV) is the most virulent pathogen in the genus , belonging to the family . Members of the family are known to replicate and assemble in cytoplasmic inclusion bodies termed viroplasms; however, the detailed mechanism underlying GCRV viroplasm formation and its specific roles in virus infection remains largely unknown. Here, we demonstrate that GCRV viroplasms form through liquid-liquid phase separation (LLPS) of the nonstructural protein NS80 and elucidate the specific role of LLPS during reovirus infection and immune evasion.
View Article and Find Full Text PDFFront Immunol
July 2024
Key Laboratory of Aquaculture Disease Control, Ministry of Agriculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
Similar to other RNA viruses, grass carp reovirus, the causative agent of the hemorrhagic disease, replicates in cytoplasmic viral inclusion bodies (VIBs), orchestrated by host proteins and lipids. The host pathways that facilitate the formation and function of GCRV VIBs are poorly understood. This work demonstrates that GCRV manipulates grass carp oxysterol binding protein 1 (named as gcOSBP1) and vesicle-associated membrane protein-associated protein A/B (named as gcVAP-A/B), 3 components of cholesterol transport pathway, to generate VIBs.
View Article and Find Full Text PDFInt J Mol Sci
February 2024
Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia.
Influenza type A virus (IAV) infection is a major cause of morbidity and mortality during influenza epidemics. Recently, a specific link between IAV infection and neurodegenerative disease progression has been established. The non-structural NS1 protein of IAV regulates viral replication during infection and antagonizes host antiviral responses, contributing to influenza virulence.
View Article and Find Full Text PDFCytokine
April 2023
Biomedical Research Center, Slovak Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic; Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Bratislava, Slovak Republic. Electronic address:
Macrophages are the most abundant cells in infected tissue and are involved in the clearing infection, and immunomodulation of the innate and adaptive immune response. NS80 virus of influenza A virus, which encodes only the first 80 aa of the NS1 protein, suppresses the immune host response and is associated with enhanced pathogenicity. Hypoxia promotes infiltration of peritoneal macrophages into the adipose tissue and production of cytokines.
View Article and Find Full Text PDFJ Immunol
January 2023
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
TANK-binding kinase 1 (TBK1) undergoes alternative splicing, and the previously reported TBK1 isoforms are negative regulators of RIG-I-like receptor-mediated type I IFN production. Although a study has suggested that grass carp TBK1 has an opposite effect at high- and low-titer of grass carp reovirus (GCRV) infection, the functions of grass carp TBK1 isoforms in GCRV infection remain unclear. In this study, we show that a TBK1 isoform from grass carp (Ctenopharyngodon idellus) named as gcTBK1_tv3, which has a 1-aa difference with zebrafish TBK1_tv3, inhibits the replication and infection of GCRV both at high and low titers of infection in C.
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