Feline Calicivirus VP2 Is Essential for the Production of Infectious Virions

  title={Feline Calicivirus VP2 Is Essential for the Production of Infectious Virions},
  author={Stanislav V. Sosnovtsev and Ga{\"e}l Belliot and Kyeong-Ok Chang and Oge C Onwudiwe and Kim Y. Green},
  journal={Journal of Virology},
  pages={4012 - 4024}
ABSTRACT The third open reading frame (ORF3) located at the 3′ end of the genomic RNA of feline calicivirus (FCV) encodes a small (12.2-kDa) minor structural protein of 106 amino acids designated VP2. Point mutations and deletions were introduced into an infectious FCV cDNA clone in order to evaluate the functional importance of ORF3 and its encoded protein, VP2. Deletion of the entire ORF3 sequence was lethal for the virus, and evidence was found for strong selective pressure to produce the… 
The Feline Calicivirus Leader of the Capsid Protein Is Associated with Cytopathic Effect
A cell-rounding phenotype associated with the transient expression of wild-type and mutagenized forms of the LC correlated with the cytopathic and growth properties of the corresponding engineered viruses.
The role of VPg in translation of calicivirus RNA
The hypothesis that VPg plays a role in translation of viral RNA during infection is supported, and a third mechanism of ribosome recruitment dependent upon protein-protein interactions between VPg and eIFs is suggested.
Leader of the Capsid Protein in Feline Calicivirus Promotes Replication of Norwalk Virus in Cell Culture
It is concluded that LC may be a viral factor which promotes the replication of NV in cells, which could provide a clue to growing the fastidious human noroviruses in cell culture.
A Bipartite Sequence Motif Induces Translation Reinitiation in Feline Calicivirus RNA*
VP2 is expressed in a translation termination/reinitiation process that is special because it requires a sequence element that could prevent dissociation of post-termination ribosomes via hybridization with 18 S rRNA.
Sapovirus Translation Requires an Interaction between VPg and the Cap Binding Protein eIF4E
It is shown that the VPg protein from porcine sapov virus, the only cultivatable sapovirus, is essential for viral translation and functions via a direct interaction with the cellular translation initiation factor eIF4E.
Characterization of the Sequence Element Directing Translation Reinitiation in RNA of the Calicivirus Rabbit Hemorrhagic Disease Virus
The sequence mapping resulted in a refined model of the reinitiation mechanism leading to VP2 expression, which stood in marked contrast to the requirements with regard to the location of the stop codon of the preceding VP1 gene.
A DNA-launched reverse genetics system for rabbit hemorrhagic disease virus reveals that the VP2 protein is not essential for virus infectivity.
Using the DNA-launch-based RHDV reverse genetics system described here, it was demonstrated that VP2 is not essential for R HDV infectivity, and studies indicate that the presence of VP2 could reduce the replication of RHDv, suggesting that it may play a regulatory role in the life cycle of RhdV.
Analysis of protein-protein interactions in the feline calicivirus replication complex.
The characterization of protein-protein interactions between the individual proteins of Feline calicivirus (FCV), a model system for other members of the family Caliciviridae, is reported and it is demonstrated that the p32 protein (the picornavirus 2B analogue) of FCV interacts with p39 (2C), p30 (3A) and p76 (3CD).
Recovery of Infectious Virus by Transfection of In Vitro-Generated RNA from Tulane Calicivirus cDNA
It is demonstrated that RNA transcripts made in vitro from the full-length genomic cDNA of TV were infectious upon transfection into permissive LLC-MK2 cells, indicating that both ORFs are essential for the replication of TV.


Translation of the Minor Capsid Protein of a Calicivirus Is Initiated by a Novel Termination-dependent Reinitiation Mechanism*
  • G. Meyers
  • Biology
    Journal of Biological Chemistry
  • 2003
VP10, a minor structural protein of the calicivirus rabbit hemorrhagic disease virus, is encoded in the small 3′-terminal open reading frame (ORF) 2 and is translated with an efficiency of ∼20% of the preceding ORF1, which is crucial for VP10 expression.
Genetic map of the calicivirus rabbit hemorrhagic disease virus as deduced from in vitro translation studies
The studies show that the N-terminal half of the ORF1 polyprotein is proteolytically cleaved to yield three nonstructural proteins of 16, 23, and 37 kDa (p16, p23, and p37, respectively).
Detection of the ORF3 polypeptide of feline calicivirus in infected cells and evidence for its expression from a single, functionally bicistronic, subgenomic mRNA.
RNA isolated from FCV-infected cells in which no subgenomic RNA smaller than 2.4 kb was detectable directed the synthesis in rabbit reticulocyte lysate of the ORF3-encoded polypeptide, suggesting that this RNA is functionally bicistronic.
RNA transcripts derived from a cloned full-length copy of the feline calicivirus genome do not require VpG for infectivity.
A system of introducing site-specific genetic changes into the genome of feline calicivirus and the recovery of infectious mutant viruses will enable studies related to the molecular basis for replication, growth restriction, and pathogenicity of this and other members of the Caliciviridae.
The subgenomic RNA of feline calicivirus is packaged into viral particles during infection.
Norwalk Virus Open Reading Frame 3 Encodes a Minor Structural Protein
The characterization of the NV ORF 3 protein expressed in a cell-free translation system and in insect cells and its association with recombinant virus-like particles (VLPs) and NV virions indicate that the ORF3 protein is a minor structural protein of the virion.
Identification and genomic mapping of the ORF3 and VPg proteins in feline calicivirus virions.
Direct N- and C-terminal sequence analysis of the purified ORF3 protein obtained by expression in bacteria demonstrated the presence of intact, uncleaved termini, suggesting that the observed difference between the calculated and the apparent masses in SDS-PAGE was not due to proteolytic processing of the protein.
Nucleotide sequence and expression of the capsid protein gene of feline calicivirus
Western immunoblot analysis of FCV-infected cells using a feline anti-FCV antiserum demonstrated that translation of the capsid protein was detectable at 3 h post Infection and continued to accumulate until 8 h postinfection, the last time examined.
The 3′ End of Norwalk Virus mRNA Contains Determinants That Regulate the Expression and Stability of the Viral Capsid Protein VP1: a Novel Function for the VP2 Protein
It is discovered that the yields of virus-like particles (VLPs) composed of VP1 are significantly reduced when this protein is expressed from ORF2 alone, and a cis role for VP2 in upregulation ofVP1 expression levels is suggested.
Cleavage of the Feline Calicivirus Capsid Precursor Is Mediated by a Virus-Encoded Proteinase
The precursor cleavage site mutations introduced into an infectious cDNA clone of the FCV genome, and transfection of RNA derived from these clones into feline kidney cells showed that efficient cleavage of the capsid precursor by the virus-encoded proteinase is a critical determinant in the growth of the virus.