Notes on Genus: Cystovirus

enveloped spheres

Type member: Pseudomonas phage f6

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 the only genus in the family Cystoviridae. These are the only phage with dsRNA genomes.

Morphology

Virions are spherical, about 85 nm in diameter, with an envelope and covered by spikes.

Genome

There are 3 linear segments of dsRNA of 6-7, 4-4.2 and 2.3-3 kbp.

Genus Genomic Organization

Each segment encodes four proteins. Proteins forming the polymerase complex are encoded on the largest segment, RNA-L. Absorption and fusion proteins that form the virion envelope are encoded on RNA-M, while proteins of the nucleocapsid core are encoded on the smallest segment, RNA-S.

Type Member Genomic Organization

The proteins encoded by the genome in their order in each segment are:
SegmentORFkDaFunction
L774.9Packaging factor
274.9RNA polymerase
435.1NTPase
185.0Structural (framework)
M104.3Lysis
617.3Membrane anchor protein
369.2Spike protein
137.6Membrane protein
S816.0Nucleocapsid surface protein
99.6Membrane assembly protein
1220.3Non-structural protein
524.1 or 23.3Endopeptidase