Notes on Genus: Caulimovirus

icosahedra

Type member: Cauliflower mosaic virus

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 is one of 7 genera in the family Caulimoviridae, which are distinctive amongst plant viruses in having double-stranded DNA. Members of the genus Caulimovirus (cauliflower mosaic virus group) have large (45-50 nm diameter) icosahedral particles. Characteristic viroplasms are produced in infected plant cells and are the sites for virus replication and particle assembly. The genus was originally very diverse but only those with 6 or 7 open reading frames are now included in this genus.

Morphology

Virions isometric, not enveloped, 45-50 nm in diameter with no obvious surface structure. The virion shell is multi-layered.

Virions composed of 16 % nucleic acid.

Genome

Monopartite, open circular, double stranded DNA of 7800-8200 base pairs. Genome has discontinuities in both strands: one in the transcribed (alpha- or minus-) strand and one to three in the non-transcribed strand.

Genus Genomic Organization

Seven open reading frames have been identified. Two RNA transcripts are thought to act as mRNAs for translation of the ORFs.

Type Member Genomic Organization

There are believed to be 7 open reading frames:

1	38 kDa	Movement protein
2	18 kDa	Helper protein involved in aphid transmission
3	15 kDa	Thought to be a DNA binding protein incorporated into the virion but now known to co-operate with P2 in aphid transmission
4	57 kDa	Coat protein (precursor of 42 kDa protein subunit of the virion shell)
5	79 kDa	Viral reverse transcriptase
6	58 kDa	Inclusion body protein involved in symptom production, host range etc.
7	11 kDa	Unknown function