Notes on Family: Roniviridae

enveloped bacilliform

Contents

• Members of this Family
• General Description
• Morphology
• Genome
• Genera in the Family
• All Known Sequences
• Curated Sequences

General Description

This family is grouped with the Coronaviridae, Mesoniviridae and Arteriviridae to form the order Nidovirales. All members of the order have enveloped particles containing a single species of single-stranded RNA that encodes for a number of proteins by means of a series of nested (Latin Nido = nest) subgenomic RNAs. Members of the family Roniviridae infect crustaceans and are distinguished by their bacilliform particles (hence the name rod-shaped nidovirus). Members of the family Arteriviridae have spherical virions 45-60nm in diameter, while those of the family Coronaviridae are more than 100nm, and all infect mammals.

Morphology

Virions enveloped and bacilliform, 150-200 nm x 40-60 nm.

Genomen

Monopartite positive sense single-stranded RNA of size about 26kb and with a 3'-polyA tail. Two large, overlapping ORFs at the 5'-end of the genome encode the major non-structural proteins and are expressed as a fusion protein by ribosomal frameshift. Downstream are about 4 other genes, encoding structural proteins, and these are expressed from a 3'-coterminal nested set of subgenomic RNAs.

Genera in the Family

There is currently only one genus:

• Okavirus