Notes on Genus: Densovirus

icosahedra

Type member: Junonia coenia densovirus

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 subfamily Densovirinae, the insect pathogens in the family Parvoviridae. Members are distinguished from those of the other genera by genome size (about 6kb), genomic organisation (particularly the ambisense strategy) and phylogenetic analysis.

Morphology

Virions isometric (icosahedral), not enveloped, 18-26 nm in diameter, made of 60 units of the capsid protein.

Genome

Linear, single-stranded monopartite DNA, about 6 kb long. Both ends have palindromic sequences that can fold to form T-shaped structures. Both plus and minus strand DNAs are encapsidated, in approximately equal amounts.

Genus Genomic Organization

There is an ambisense coding strategy. Three non-structural proteins are encoded in different ORFs in one sense (using a single mRNA promoter and leaky scanning). On the complementary strand, a single structural ORF is translated by a leaky scanning strategy to produce virion proteins of different sizes.

Type Member Genomic Organization

There are 3 non-structural ORFs in one orientation:
  1. NS1, 22.5 kDa
  2. NS2, 31.19 kDa
  3. NS3, 63.4 kDa
The single capsid protein ORF (87.9 kDa) is in the opposite orientation. It is translated by leaky scanning to produce (probably 4) products of differing length (with the same C-terminus).