Notes on Genus: Hemivirus

variable ovoid or spheroid
variable ovoid or spheroid

Type member: Drosophila melanogaster copia virus

Contents

General Description

This is one of the genera (distinct phylogenetic lineages) in the retroelement family Pseudoviridae. DNA synthesis is primed by a half t-RNA molecule, hence the name (from the Greek hemi = half).

Morphology

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

Genome

The major molecule is a positive sense ssRNA transcript of 4.5-6.5 kb flanked by Long Terminal Repeats (LTRs).

Genus Genomic Organization

The two major genes gag and pol are produced either from a single ORF or from 2 ORFs (either by ribosomal frameshift or via a spliced mRNA). 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 163 kDa. The gag is translated from a spliced mRNA.