Notes on Genus: Barnavirus
Type member: Mushroom bacilliform virus
The genus Barnavirus
virus) is the only genus in the family Barnaviridae
. The single member is the only known ssRNA virus that infects fungi and it has distinctive bacillifom virions.
Virions are bacilliform, not enveloped, about 18-20 nm in diameter and 48-53 nm long. There are no obvious surface projections. The virions contain about 20 % nucleic acid.
Monopartite, linear, single stranded, positive sense RNA of about 4kb. The 3' terminus has no poly(A) tract and there appears to be no cap at the 5' terminus.
Genus Genomic Organization
A total of seven open reading frames have been identified but it is not clear whether all are expressed in vivo
. The coat protein is towards the 3'-terminus and is probably expressed from a 3'-terminal subgenomic RNA.
Type Member Genomic Organization
Seven open reading frames have been identified:
|1. ||20 kDa||unknown function|
|2. ||73 kDa||probable replication protein|
|3. ||47 kDa||RNA-dependent RNA polymerase|
|4. ||22 kDa||Coat protein, probably translated from a subgenomic RNA|
|5. ||8 kDa||unknown function: may not be expressed|
|6. || 6.5 kDa||unknown function: may not be expressed|
|7. ||6 kDa||unknown function: may not be expressed|