Identification of a calicivirus isolate of unknown origin

Oehmig, Angelika; Büttner, Mathias; Weiland, Frank; Werz, William; Bergemann, Klaus; Pfaff, Eberhard

doi:10.1099/vir.0.19042-0

Cited by 50 publications

(39 citation statements)

References 47 publications

(52 reference statements)

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“…2A). Consistent with a previous report (32), isolate 2117, which was identified as a contaminating agent in fetal bovine serum, clustered closely with CaCV ( Fig. 2A).…”

Section: Resultssupporting

confidence: 92%

The Feline Calicivirus Leader of the Capsid Protein Is Associated with Cytopathic Effect

Abente

Sosnovtsev

Sandoval-Jaime

et al. 2013

J Virol

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Open reading frame 2 (ORF2) of the feline calicivirus (FCV) genome encodes a capsid precursor that is posttranslationally processed to release the mature capsid protein (VP1) and a small protein of 124 amino acids, designated the leader of the capsid (LC). To investigate the role of the LC protein in the virus life cycle, mutations and deletions were introduced into the LC coding region of an infectious FCV cDNA clone. Three cysteine residues that are conserved among all vesivirus LC sequences were found to be critical for the recovery of FCV with a characteristic cytopathic effect in feline kidney cells. 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 host cellular protein annexin A2 was identified as a binding partner of the LC protein, consistent with a role for the LC in mediating host cell interactions that alter the integrity of the cell and enable virus spread.M embers of the family Caliciviridae are small nonenveloped viruses that contain a positive-sense single-stranded RNA genome. Feline calicivirus (FCV) is in the genus Vesivirus of the family and has been an important model for studying calicivirus replication because it grows efficiently in cell culture and has a reverse genetics system (1-5). The RNA genomes of caliciviruses range in size from ϳ6.7 to 8.5 kb and typically encode 8 or 9 viral proteins from two (Sapovirus, Nebovirus, and Lagovirus) or three (Norovirus and Vesivirus) open reading frames (ORFs). A unique ORF4 in the murine norovirus genome that encodes a protein reported to downregulate the innate immune response has been identified (6). The 5= end of the viral RNA genome is covalently linked to a VPg protein; the 3= end of the genome is polyadenylated (2, 7-9). The infectious virion is composed of 180 copies of the major capsid protein VP1 and 1 to 10 copies of the minor structural protein VP2, which together form a capsid around the VPg-linked genome (10-15). The genomic RNA serves as a template for translation of the ORF1 polyprotein that is proteolytically cleaved by the viral protease to release the nonstructural proteins (16,17), and an ϳ2.2-to 2.6-kb subgenomic bicistronic RNA template is used for the translation of VP1 and VP2 (7, 18). A genetic feature unique to members of the genus Vesivirus is expression of the major capsid protein from ORF2 as a precursor protein (5,(18)(19)(20). This precursor is processed in trans by the viral protease to release two proteins: the leader of the capsid (LC) and the mature capsid protein (VP1) (5,19,21,22). The function of the LC protein is not clear, but cleavage of the precursor to release LC and VP1 is essential for the recovery of infectious virions (5). Transient expression of the LC was reported to enhance replication of a human norovirus RNA replicon (23), and an increase in the level of mRNA for the low-density lipoprotein receptor (LDLR) was observed (24). We showed previo...

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“…2A). Consistent with a previous report (32), isolate 2117, which was identified as a contaminating agent in fetal bovine serum, clustered closely with CaCV ( Fig. 2A).…”

Section: Resultssupporting

confidence: 92%

The Feline Calicivirus Leader of the Capsid Protein Is Associated with Cytopathic Effect

Abente

Sosnovtsev

Sandoval-Jaime

et al. 2013

J Virol

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“…We demonstrate here that the VP2 protein is essential for the production of infectious FCV virions. Our data are consistent with previous suggestions (7,27,38,43) that VP2 is involved in the maturation and assembly of calicivirus particles.…”

Section: Discussionsupporting

confidence: 83%

“…Their virions are 27 to 40 nm in diameter and have icosahedral symmetry. The virion capsid is comprised of 180 copies of the major structural protein, VP1 (29, 31), and a minor structural protein designated VP2 (7,27,38,43). The capsid surrounds the VPg-linked polyadenylated RNA genome (2,6,14,23), and in at least two caliciviruses, rabbit hemorrhagic disease virus (RHDV) and feline calicivirus (FCV), a VPg-linked ϳ2.2-to 2.6-kb subgenomic-size RNA is also packaged into virions (23,25).…”

mentioning

confidence: 99%

Feline Calicivirus VP2 Is Essential for the Production of Infectious Virions

Sosnovtsev

Belliot

Chang

et al. 2005

J Virol

115

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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 VP2 protein. Extended deletions in the 5 end and small deletions in the 3 end of ORF3, as well as the introduction of stop codons into the ORF3 sequence, were tolerated by the viral replication machinery, but infectious virus could not be recovered. Infectious virus particles could be rescued from a full-length FCV cDNA clone encoding a nonfunctional VP2 when VP2 was provided in trans from a eukaryotic expression plasmid. Our data indicate that VP2, a protein apparently unique to the caliciviruses, is essential for productive replication that results in the synthesis and maturation of infectious virions and that the ORF3 nucleotide sequence itself overlaps a cis-acting RNA signal at the genomic 3 end.Caliciviruses are small, nonenveloped, positive-strand RNA viruses that infect a broad range of hosts. Their virions are 27 to 40 nm in diameter and have icosahedral symmetry. The virion capsid is comprised of 180 copies of the major structural protein, VP1 (29, 31), and a minor structural protein designated VP2 (7,27,38,43). The capsid surrounds the VPg-linked polyadenylated RNA genome (2,6,14,23), and in at least two caliciviruses, rabbit hemorrhagic disease virus (RHDV) and feline calicivirus (FCV), a VPg-linked ϳ2.2-to 2.6-kb subgenomic-size RNA is also packaged into virions (23,25). The RNA genomes of caliciviruses range in size from 7.3 to 8.3 kb and are organized into either two or three major open reading frames (ORFs) (9). In the genera Lagovirus and Sapovirus of the family Caliciviridae, the nonstructural proteins and the structural protein VP1 are encoded in the same ORF. In the genera Vesivirus and Norovirus, VP1 is encoded in a separate ORF. In all genera, a genomic-length RNA serves as a template for synthesis of the nonstructural polyprotein while the 2.2-to 2.6-kb bicistronic subgenomic RNA is used for translation of the VP1 and VP2 proteins (3,26,28).All caliciviruses encode the VP2 protein in a separate ORF near the 3Ј end of the genome (ORF3 for noroviruses and vesiviruses and ORF2 for sapoviruses and lagoviruses). Comparative sequence analyses of this terminal ORF and the deduced VP2 amino acid sequence indicate that this region of the genome is highly variable in sequence between genera, with as little as 10% amino acid similarity. In addition, these proteins show significant variation in length, ranging from 106 (FCV) to 268 (norovirus MD-145) amino acids (aa). The expression of VP2 in calicivirus-infected cells has been reported for FCV and RHDV (13,17,42). For FCV, the level of VP2 expression has been estimated to ...

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“…The NS6-NS7 protein was also detected in porcine sapovirus-infected cells (28). Similar to the case for sapoviruses, vesivirus also produces the NS6-NS7 protein (fused protease-polymerase) (52,53,(59)(60)(61), whereas noroviruses and lagoviruses produce an individual protease and polymerase, NS6 and NS7, respectively (51,53,(62)(63)(64)(65)(66)(67). The biological functions of the other sapovirus NS proteins have not been experimentally determined; however, NS3 and NS5 have a typical calicivirus NTPase motif (GAPGIGKT) and VPg motifs (KGKTK and DDEYDE), respectively ( Fig.…”

Section: Genomic Organizationmentioning

confidence: 72%

Comprehensive Review of Human Sapoviruses

et al. 2015

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SUMMARY Sapoviruses cause acute gastroenteritis in humans and animals. They belong to the genus Sapovirus within the family Caliciviridae . They infect and cause disease in humans of all ages, in both sporadic cases and outbreaks. The clinical symptoms of sapovirus gastroenteritis are indistinguishable from those caused by noroviruses, so laboratory diagnosis is essential to identify the pathogen. Sapoviruses are highly diverse genetically and antigenically. Currently, reverse transcription-PCR (RT-PCR) assays are widely used for sapovirus detection from clinical specimens due to their high sensitivity and broad reactivity as well as the lack of sensitive assays for antigen detection or cell culture systems for the detection of infectious viruses. Sapoviruses were first discovered in 1976 by electron microscopy in diarrheic samples of humans. To date, sapoviruses have also been detected from several animals: pigs, mink, dogs, sea lions, and bats. In this review, we focus on genomic and antigenic features, molecular typing/classification, detection methods, and clinical and epidemiological profiles of human sapoviruses.

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Identification of a calicivirus isolate of unknown origin

Cited by 50 publications

References 47 publications

The Feline Calicivirus Leader of the Capsid Protein Is Associated with Cytopathic Effect

The Feline Calicivirus Leader of the Capsid Protein Is Associated with Cytopathic Effect

Feline Calicivirus VP2 Is Essential for the Production of Infectious Virions

Comprehensive Review of Human Sapoviruses

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