| Totivirus | |
|---|---|
 | |
| Saccharomyces cerevisiae virus L-A capsid protein structure and homodimer of the gag capsid protei | |
Virus classification | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Duplornaviricota |
| Class: | Chrymotiviricetes |
| Order: | Ghabrivirales |
| Family: | Orthototiviridae |
| Genus: | Totivirus |
| Synonyms[2] | |
| |
Totivirus is a genus ofdouble-stranded RNA viruses in the familyOrthototiviridae. Fungi serve as natural hosts. The name of the group derives fromLatintoti which means undivided or whole. There are 32 species in this genus.[3][4]
Viruses in the genusTotivirus are non-enveloped, withicosahedral symmetry, and T=2 architecture. The diameter is around 40 nm.[3]
Totiviruses have agenome of 4700–6700nucleotides in length and only a single copy of the genome is present in the particle. Thenucleic acid content of a totivirus capsid is one segment of lineardouble stranded RNA. Thegenome contains two large overlappingopen reading frames (ORFs). Theseopen reading frames (ORFs) code for a capsid protein (CP) and anRNA-dependent RNA polymerase (RdRp). The 5' end of the positive strand of the dsRNA genome has no cap and is very structured. Totiviruses contain a long 5' untranslated region (5' UTR) which functions as aninternal ribosome entry site (IRES). Totiviruses can have satellite RNAs encoding atoxin.[3][5]
Viral replication is cytoplasmic. Entry into the host cell is achieved by virus remains intracellular. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. Translation takes place by -1 ribosomal frameshifting. The virus exits the host cell by cell-to-cell movement. FungiSaccharomyces cerevisiae andsmut serve as the natural host. The virus is transmitted during cell division, sporogenesis, and cell fusion.[3]
The genusTotivirus contains the following species:[4]