Notes on Genus: Totivirus

icosahedra

Type member: Saccharomyces cerevisiae virus L-A

Contents

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

General Description

This genus contains those members of the family Totiviridae that infect yeasts and smut fungi. The name reflects the fact that the genome is undivided (Latin: totus).

Morphology

Virions isometric, 40 nm in diameter, with T=1 and a dimer of the coat protein as the asymmetric unit.

Genome

Monopartite, linear, double stranded DNA of 3200-6700 base pairs. Satellite or defective RNAs occur in some isolates.

Genus Genomic Organization

The genome usually has two large, overlapping ORFs on the positive strand. The first encodes the coat protein. The second ORF is an RNA-dependent RNA polymerase and is believed to be expressed as a fusion protein via a translational frameshift with ORF1.

Type Member Genomic Organization

There are two large, overlapping ORFs on the positive strand:
1. 76 kDaCoat protein (gag)
2.   88-99 kDa Polymerase (pol): RNA-dependent RNA polymerase expressed as a 171 kDa fusion protein with gag by a -1 ribosomal frameshift