Notes on Genus: Sapovirus

icosahedra

Type member: Sapporo virus

Contents

Members of this Genus
General Description
Morphology
Electron Micrograph
Genome
Genus Genomic Organization
Genome Map
Type Member Genomic Organization
Curated Sequences

General Description

This is one of the genera in the family Calicviridae. In common with members of the genera Lagovirus and Nebovirus, the coat protein is at the C-terminus of the polyprotein but the genera have different host specificities and are distinct in phylogenetic analyses.

Morphology

Virions isometric (icosahedral), not enveloped, 35-40 nm in diameter, made of 90 dimers of the coat protein. There are 32 cup-shaped depressions at each of the fivefold and threefold axes.

Genome

Monopartite positive sense single-stranded RNA c. 7.4 kb in length with a genome-linked protein (VPg) at the 5'-terminus and a 3'-polyA tail.

Genus Genomic Organization

The RNA encodes a polyprotein that has (from N- to C- termini) helicase, VPg, protease, polymerase and coat protein domains. There are one or perhaps two additional, smaller, ORFs.

Type Member Genomic Organization

The genome of about 7,400 nucleotides is translated into:
  1. Polyprotein of 251.3 kDa, which is proteolytically processed into 7 or more mature proteins including (in order from N- to C- termini) helicase, VPg, protease, polymerase and coat protein
  2. Possible ORF (17.5 kDa) nested within the polyprotein
  3. ORF2 of 17.8 kDa that may be a minor structural component of the virion