Notes on Genus: Alphanodavirus

icosahedra
icosahedra

Type member: Nodamura virus

Contents

General Description

This is one of two genera in the family Nodaviridae and consists of those viruses that infect insects. The name is derived from the Japanese town (Nodamura) where the type member was first isolated.

Morphology

Virions isometric (icosahedral), not enveloped, 29-32 nm in diameter without any distinctive surface struture.

Genome

Bipartite positive sense single-stranded RNA without 3'-polyA tails of length 3.0-3.2 (RNA1) and 1.3-1.4kb (RNA2).

Genus Genomic Organization

RNA1 has one large ORF encoding an RNA polymerase (protein A) and one or two smaller proteins (B1 and B2). RNA2 has a single ORF, a coat protein precursor (protein alpha), which is subsequently cleaved into two products (beta and gamma).

Type Member Genomic Organization

RNA1 (3204 nts) encodes two proteins:
  • Polymerase protein A (116 kDa)
  • Protein B2 (15 kDa) of unknown function
RNA2 (1336 nts) encodes the coat protein precursor alpha (43 kDa) which is subsequently cleaved into the two products, beta (38 kDa) and gamma (5 kDa).