title: Human enteric Caliciviridae: a new prevalent small round-structured virus group defined by RNA-dependent RNA polymerase and capsid diversity.
abstract: Sequence comparison of the RNA-dependent RNA polymerases of small round-structured viruses (SRSVs) from 10 recent U.K. outbreaks of gastroenteritis revealed significant genetic variation. Computer analyses indicated that these viruses can be divided into two discrete groups. SRSV group I contains the previously characterized antigenic type 1 Norwalk and type 3 Southampton viruses. The amino acid sequences of the RNA polymerase, capsid and ORF3 of these two viruses are relatively similar (about 92%, 69% and 72% amino acid identity, respectively). A representative member of group II SRSVs, Bristol virus, was subjected to a detailed genetic analysis. Bristol virus is a recent antigenic type 2 isolate from a U.K. hospital outbreak of gastroenteritis. Using a single clinical sample the 3'-terminal 3881 nucleotide cDNA sequence [excluding the poly(A) tail] of this virus was determined. Analysis of the sequence revealed significant differences from those of group I viruses with the RNA polymerase region, capsid and ORF3 showing only about 62%, 43% and 30% amino acid identity respectively with the equivalent proteins of the Norwalk and Southampton viruses. These data suggest that the morphologically identical SRSVs belong to at least two genetically distinct groups.
authors.affiliation: Department of Molecular Microbiology, University Medical School, Southampton General Hospital, U.K.
authors.forename: S M
authors.initials: SM
authors.lastname: Green
authors.forename: K E
authors.initials: KE
authors.lastname: Dingle
authors.forename: P R
authors.initials: PR
authors.lastname: Lambden
authors.forename: E O
authors.initials: EO
authors.lastname: Caul
authors.forename: C R
authors.initials: CR
authors.lastname: Ashley
authors.forename: I N
authors.initials: IN
authors.lastname: Clarke
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002139:Caliciviridae / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D002213:Capsid / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D005759:Gastroenteritis / Q000382:microbiology; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D009663:Norwalk virus / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012703:Serotyping
chemical_list: D012321:DNA-Directed RNA Polymerases