Intracellular cleavage of σA protein of avian reovirus

Ji, Wen T.; Lin, Feng; Wang, Ying C.; Shih, Wing L.; Lee, Long H.; Liu, Hung-Jen

doi:10.1016/j.virusres.2010.01.003

Cited by 5 publications

(4 citation statements)

References 22 publications

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“…This suggests that there may be a different mechanism between aquareovirus and ARV. In addition, intracellular post-translational cleavage of σA was found in ARV [28], but not observed in σ2 of MRV or in VP6 of aquareovirus, hinting that VP6 is more close to MRV σ2 in some biological properties. The results of VP6 colocalization with NS80 in cells suggest that the core protein component VP6 might be expressed and assembled in viral factory of the cytoplasm, similar to the σ2 and μNS in MRV [22].…”

Section: Discussionmentioning

confidence: 99%

Aquareovirus protein VP6 colocalizes with NS80 protein in infected and transfected cells

Wen

Yan

Shao

et al. 2013

Virol J

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BackgroundAquareovirus particle is comprised of central core and outer capsid, which is built by seven structural proteins (VP1-VP7). The protein VP6 has been identified to be a clamp protein of stabilizing inner core frame VP3, and bridging outer shell protein VP5. However, the biological properties of VP6 in viral life cycle remain unknown.ResultsThe recombinant VP6 (rVP6) of aquareovirus was expressed in E. coli, and the polyclonal antibody against VP6 was generated by using purified rVP6 in this study. Following the preparation of VP6 antibody, the VP6 component in aquareovirus infected cells and purified viral particles was detected by Immunoblotting (IB) assay. Furthermore, using Immunofluorescence (IF) microscopy, singly transfected VP6 protein was observed to exhibit a diffuse distribution mainly in the cytoplasm, while it appeared inclusion phenotype in infected cells. Meanwhile, inclusion structures were also identified when VP6 was coexpressed with nonstructural protein NS80 in cotransfected cells.ConclusionsVP6 can be recruited by NS80 to its inclusions in both infected and transfected cells. The colocalization of VP6 and NS80 is corresponding to their homologous proteins σ2 and μNS in MRV. Our results suggest that VP6 may play a significant role in viral replication and particle assembly.

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Section: Discussionmentioning

confidence: 99%

Aquareovirus protein VP6 colocalizes with NS80 protein in infected and transfected cells

Wen

Yan

Shao

et al. 2013

Virol J

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“…Thus, the ARV M3 gene expresses three protein isoforms, whereas only two are expressed by its MRV counterpart. Similarly to μNS, the ARV structural proteins μB and σA have been shown to be partially cleaved near their amino termini to generate small amino-terminal peptides (μBN and σAN, respectively) and larger carboxy-terminal proteins (μBC and σAC, respectively) (Ji et al , 2010; Varela et al , 1996). Altogether, these results allow us to expand the protein repertoire known to be expressed by ARV to 18 polypeptides, 12 of which are primary translation products and six of which are non-structural proteins ().…”

Section: Discussionmentioning

confidence: 99%

Avian and mammalian reoviruses use different molecular mechanisms to synthesize their μNS isoforms

Busch

Rodríguez-Grille

Casal

et al. 2011

Journal of General Virology

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Previous reports revealed that the M3 gene of both avian and mammalian reoviruses express two isoforms of the non-structural protein mNS in infected cells. The larger isoforms initiate translation at the AUG codon closest to the 59 end of their respective m3 mRNAs, and were therefore designated mNS. In this study we have performed experiments to identify the molecular mechanisms by which the smaller mNS isoforms are generated. The results of this study confirmed the previous findings indicating that the smaller mammalian reovirus mNS isoform is a primary translation product, the translation of which is initiated at the internal AUG-41 codon of mammalian reovirus m3 mRNA. Our results further revealed that the smaller avian reovirus mNS isoform originates from a specific post-translational cleavage site near the amino terminus of mNS. This cleavage produces a 55 kDa carboxy-terminal protein, termed mNSC, and a 17 kDa amino-terminal polypeptide, designated mNSN. These results allowed us to extend the known avian reovirus protein-encoding capacity to 18 proteins, 12 of which are structural proteins and six of which are non-structural proteins. Our finding that avian and mammalian reoviruses use different mechanisms to express their mNSC isoforms suggests that these isoforms are important for reovirus replication.

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“…Viral genomic segments can be separated electrophoretically into three different size classes, named L (Large; three segments), M (Medium; three segments) and S (Small; four segments). The ARV genome expresses at least 8 structural and four non-structural proteins (Bodelon et al, 2001), but the protein repertoire of ARV is increased to at least 12 structural proteins and six non-structural proteins by posttranslational cleavage of some viral proteins (Busch et al, 2011;Ji et al, 2010;Varela et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Avian reovirus-triggered apoptosis enhances both virus spread and the processing of the viral nonstructural muNS protein

et al. 2014

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Avian reovirus non-structural protein muNS is partially cleaved in infected chicken embryo fibroblast cells to produce a 55-kDa carboxyterminal protein, termed muNSC, and a 17-kDa aminoterminal polypeptide, designated muNSN. In this study we demonstrate that muNS processing is catalyzed by a caspase 3-like protease activated during the course of avian reovirus infection. The cleavage site was mapped by site directed mutagenesis between residues Asp-154 and Ala-155 of the muNS sequence. Although muNS and muNSC, but not muNSN, are able to form inclusions when expressed individually in transfected cells, only muNS is able to recruit specific ARV proteins to these structures. Furthermore, muNSC associates with ARV factories more weakly than muNS, sigmaNS and lambdaA. Finally, the inhibition of caspase activity in ARV-infected cells does not diminish ARV gene expression and replication, but drastically reduces muNS processing and the release and dissemination of progeny viral particles.

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Intracellular cleavage of σA protein of avian reovirus

Cited by 5 publications

References 22 publications

Aquareovirus protein VP6 colocalizes with NS80 protein in infected and transfected cells

Aquareovirus protein VP6 colocalizes with NS80 protein in infected and transfected cells

Avian and mammalian reoviruses use different molecular mechanisms to synthesize their μNS isoforms

Avian reovirus-triggered apoptosis enhances both virus spread and the processing of the viral nonstructural muNS protein

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