Notes on Family: Roniviridae
enveloped bacilliform
Contents
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:
