Coronaviridae is a family of virus of the order Nidovirales. The name is derived from their rod like shape - rod like nidoviridae.
Virology
The viruses in this family are enveloped, bacilliform-shaped, ~150-200 nanometers (nm) in length and 40-60 nm in diameter. The envelope has surface projections. These surface projections are prominent, distinctive peplomers surrounded by a prominent fringe. The nucleocapsid is elongated and has a helical symmetry with a diameter of 20-30 nm.
The genome is non segmented, linear,positive sense single stranded RNA 26 kilobases in length. It is capped, and polyadenylated.
The genome encodes 6 open reading frames (ORF). The 5' and largest OFRs (OFR1a and ORF 1b) encode the RNA polymerase and other non structurla proteins. OFR 1a is encoded by the genomic RNA. ORF 1b is encoded by a frameshift within OFR 1a and the sequence 3' of ORF 1b. The structural proteins (N, Gp116, Gp64 and ORF 4) are transcribed as sub genomic RNAs.
Proein encoded with the genome include a cysteine protease, RNA-dependent RNA polymerase, helicase and metal ion binding domains, nucleoprotein, and S glycoproteins.
This family is grouped with the Coronaviridae 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.
Genome
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
Virology
The viruses in this family are enveloped, bacilliform-shaped, ~150-200 nanometers (nm) in length and 40-60 nm in diameter. The envelope has surface projections. These surface projections are prominent, distinctive peplomers surrounded by a prominent fringe. The nucleocapsid is elongated and has a helical symmetry with a diameter of 20-30 nm.
The genome is non segmented, linear,positive sense single stranded RNA 26 kilobases in length. It is capped, and polyadenylated.
The genome encodes 6 open reading frames (ORF). The 5' and largest OFRs (OFR1a and ORF 1b) encode the RNA polymerase and other non structurla proteins. OFR 1a is encoded by the genomic RNA. ORF 1b is encoded by a frameshift within OFR 1a and the sequence 3' of ORF 1b. The structural proteins (N, Gp116, Gp64 and ORF 4) are transcribed as sub genomic RNAs.
Proein encoded with the genome include a cysteine protease, RNA-dependent RNA polymerase, helicase and metal ion binding domains, nucleoprotein, and S glycoproteins.
This family is grouped with the Coronaviridae 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.
Genome
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
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