Notes on Genus: Sirevirus

variable ovoid or spheroid
variable ovoid or spheroid

Type member: Glycine max SIRE1 virus


General Description

This is one of the genera (distinct phylogenetic lineages) in the retroelement family Pseudoviridae. The name is derived from the type member, Glycine max SIRE-1 virus.


Virus-like particles (VLPs) are poorly studied but seem to be non-enveloped, ovoid or spheroid in shape and 60-80 nm in diameter.


The major molecule is a positive sense ssRNA transcript of 4.5-10.5 kb flanked by Long Terminal Repeats (LTRs).

Genus Genomic Organization

Genome organisation is variable with from 1 to 3 ORFs encoding the gag, pol and (sometimes) env proteins. Second and third ORFs (where present) are in separate reading frames and are probably translated by ribosomal frameshift.. As in other genera of the family, the pol contains protease (PR), integrase (IN) and reverse transcriptase (RT) domains in that order.

Type Member Genomic Organization

There is a single gag-pol ORF of 177 kDa. The sequence may be incomplete with an env protein expressed by ribosomal frameshift at the C-terminus of the gag-pol.