Notes on Family: Betasatellites

no particles of their own

Contents

Members of this Family
General Description
Morphology
Genome
Genera in the Family
All Known Sequences
Curated Sequences

General Description

Satellites are sub-viral agents composed of nucleic acid molecules that depend for their replication on co-infection of a host cell with a specific helper virus. Nucleotide sequences are substantially distinct from those of the genomes of the helper virus and of the host. Replication of the helper virus is often decreased and virus symptoms may be modified.

Satellite nucleic acids consist of those satellites that do not encode their own coat protein (unlike satellite viruses) but are encapsidated in that of the helper virus. Particles containing satellite nucleic acid are therefore antigenically identical to those of the helper virus but can sometimes be distinguished by physical features such as sedimentation rates.

All known single stranded satellite DNAs are associated with plant viruses. Betasatellites are associated with monpartite members of the genus Begomovirus. The circular genome encodes a single protein of 14-16 kDa (C1) in the complementary (negative) sense that is responsible for symptom production.

Morphology

There are no distinctive virions because they are encapsidated in the coat protein of their helper virus.

Genome

Monopartite, circular, ssDNA of 1300-1400nt.

Genera in the Family

Satellites are not formally classified into families, genera and species. All betasatellites so far discovered are treated here as Begomovirus betasatellites.