Notes on Genus: Levivirus
Type member: Enterobacteria phage MS2
This is one of the genera in the family Leviviridae
. Members have a genome of less than 4 kb which encodes a separate lysis gene.
Virions isometric (icosahedral), not enveloped, c.
26 nm in diameter.
Monopartite, linear, postive sense ssRNA of 3.5-3.6 kb.
Genus Genomic Organization
There are 4 ORFs including a single capsid protein, a replicase and a lysis protein.
Type Member Genomic Organization
The 4 ORFs are
- A protein, 43.9 kDa (required for attachment and virion maturation)
- Capsid protein, 13.8 kDa
- Lysis protein, 8.9 kDa
- Replicase, 60.8 kDa