Tetraviridae. Tetraviridae

Description of Tetraviridae adapted from ICTVdb Virion Properties Morphology Virions consist of a capsid. Virus capsid is not enveloped, round with quasi- icosahedral symmetry (T=4). The capsid is isometric and has a diameter of 40 nm. Capsids appear hexagonal in outline. The capsid surface structure reveals a regular pattern with distinctive features (that are resolved by cryo-electron microscopy and image reconstruction). The capsomer arrangement is clearly visible in cryo-electron microscopy. Physicochemical and Physical Properties Virions have a buoyant density in CsCl of 1.28-1.3 g cm-3. Nucleic Acid The Mr of the genome constitutes 11% of the virion by weight. The genome is not segmented and contains a single molecule of, or segmented and consists of two segments of linear, positive-sense, single-stranded RNA. The complete genome is 5500-8000 nucleotides long, is sequenced, complete sequence is about 5500 nucleotides long, is sequenced, but only an estimate is available, complete sequence is 2500 nucleotides long. Proteins The viral genome encodes structural proteins. Lipids Lipids are undetermined (however the amino terminus of the coat protein precursor, alpha, is blocked by an unidentified entity). Carbohydrates Carbohydrates have not been reported.