Notes on Genus: Megabirnavirus
Type member: Rosellinia necatrix megabirnavirus 1
The genus is the only member of the family Megabirnaviridae
and currently consists of only one virus. The virus infects fungi and its genome is much larger than that of other dsRNA viruses. It is named for its large (mega
Virions are isometric (icosahedral) and about 50 nm in diameter.
Bipartite dsRNA with segments of about 9 and 7 kbp.
Genus Genomic Organization
There are two ORFs predicted on each RNA segment.
Type Member Genomic Organization
RNA1 encodes the single major capsid protein of 135 kDa and an RNA polymerase of 123 kDa that may be expressed with the capsid protein by ribosomal frameshift. The two ORFs on RNA2 (152 and 24 kDa) have no homologies with known proteins and their functions are therefore unknown.