Notes on Genus: Carmovirus
Type member: Carnation mottle virus
The genus Carmovirus
ttle virus group) is one of 11 genera in the family Tombusviridae
. All the genera are morphologically similar, with icosahedral particles and small, (usually) monopartite ss RNA genomes. The members of the genus resemble those of the genera Aureusvirus
in having 5 open reading frames and a large (>35 kDa) coat protein, but their genomes are smaller (<4.4 kb) and the coat protein gene is at the 3'-end of the RNA.
Virions isometric (icosahedral; T=3), not enveloped and about 30 nm in diameter. The nucleocapsids have an obvious regular, apparently round, surface structure. 32 capsomeres per nucleocapsid (virion composed of 180 protein subunits).
Virions composed of 17 % nucleic acid.
Monopartite, linear, single stranded, positive sense RNA of length 4000-4100 nucleotides. The 3' terminus has no poly(A) tract. The 5' terminus probably has a methylated nucleotide cap (the terminus is protected but the presence of a cap has been demonstrated only in carnation mottle virus).
Genus Genomic Organization
For most of the well-studied members, there are five open reading frames, three of which are translated from two subgenomic RNAs:
|1. ||c. 28 kDa||Polymerase|
|2. ||c. 88 kDa||Polymerase readthrough|
|3. ||7-8 kDa||Movement protein 1 (cell-to-cell transport, translated from subgenomic RNA 1) |
|4. ||8-9 kDa||Movement protein 2 (cell-to-cell transport, translated from subgenomic RNA 1) |
|5. ||c. 40 kDa||Coat protein, translated from subgenomic RNA2|
Type Member Genomic Organization
The RNA is translated into five putative products:
|1. || 27 kDa||Polymerase|
|2. ||88 kDa||Polymerase readthrough|
|3. ||7 kDa||Movement protein 1 (cell-to-cell transport, translated from subgenomic RNA 1; 1689 nt)|
|4. ||8 kDa||Movement protein 2 (cell-to-cell transport, translated from subgenomic RNA1) |
|5. ||38 kDa||Coat protein, translated from subgenomic RNA2 (1431 nt)|