Leviviridae. Leviviridae

Description of Leviviridae adapted from ICTVdb Virion Properties Morphology Phages consist of a capsid and are not enveloped. Virions are not tailed. Capsid/nucleocapsid is round and exhibits icosahedral symmetry (T=3). The isometric capsid has a diameter of about 26 nm. Capsids appear round. The capsid consists of 32 capsomers. Physicochemical and Physical Properties The molecular mass (Mr) of virions is 3.6-4.2 x 106 (depending on the genus). Virions have a buoyant density in CsCl of 1.46 g cm-3. The sedimentation coefficient is 80-84 S20w. Virions are sensitive to treatment with detergents; not sensitive to treatment with ether and chloroform. The infectivity is reduced after exposure to irradiation. Nucleic Acid The Mr of the genome constitutes 30% of the virion by weight. The genome is not segmented and contains a single molecule of linear positive-sense, single-stranded RNA. The complete genome is 3466-4276 nucleotides long. The genome has a base ratio of 50 % guanine; 50 % adenine. Proteins The viral genome encodes structural proteins and non-structural proteins. Virions consist of 2 structural protein(s) located in the capsid. Lipids Lipids are not reported. Genome Organization and Replication By itself, genomic nucleic acid is infectious. Translation: The genome replicates in the cytoplasm.