Notes on Genus: Machlomovirus
Type member: Maize chlorotic mottle virus
The genus Machlomovirus
ttle virus group) currently contains only one member. It 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. This genus is most similar to the genus Carmovirus
. However, the coat protein is smaller, only one, rather than two, subgenomic RNAs are produced and there is rather little sequence homology. Unlike other members of the family, the virus has an insect vector.
Virions isometric (icosahedral), not enveloped, 30 nm in diameter.
Monopartite, linear, single stranded positive sense RNA, 4437 nucleotides long. Some virions also contain a subgenomic RNA of 1100 nucleotides. The 3' terminus has no poly(A) tract. The 5' terminus has a methylated nucleotide cap, with sequence m7
Genus Genomic Organization
Six open reading frames have been identified, with the coat protein expressed from a 3'-coterminal subgenomic RNA.
Type Member Genomic Organization
The six open reading frames identified are:
|1. ||32kDa||ORF1, unknown function|
|2. ||50 kDa||Polymerase |
|3. ||111 kDa || Polymerase readthrough|
|4. ||9 kDa ||Movement protein ORF3|
|5. ||33 kDa ||Movement protein ORF3 readthrough|
|6. ||25 kDa||Coat protein expressed from a 3'-coterminal subgenomic RNA|