Sequence comparison of small round-structured viruses from gastroenteritis outbreaks revealed they belong to at least two genetically distinct groups based on RNA polymerase and capsid diversity.
Morphologically identical small round-structured viruses causing gastroenteritis belong to at least two genetically distinct groups based on RNA polymerase and capsid diversity.
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.
Green et al. (Mon,) conducted a other in Gastroenteritis. Sequence comparison of RNA-dependent RNA polymerases was evaluated on Genetic variation and grouping of small round-structured viruses. Sequence comparison of small round-structured viruses from gastroenteritis outbreaks revealed they belong to at least two genetically distinct groups based on RNA polymerase and capsid diversity.