title: Togaviridae.
abstract: The family Togaviridae comprises four genera: Alphavirus (with 26 species), Rubivirus (one species), Pestivirus (three species), and Arterivirus (one species). The main characteristics of the member viruses are: (i) the virus particles are spherical, 50-70 nm in diameter, including an envelope with surface projections that incorporate two or three polypeptides, usually glycosylated; (ii) the nucleocapsid comprises a core protein and a single strand of positive-sense RNA, molecular weight about 4 X 10(6); where characterized, the RNA has an m7G 'cap' at the 5' end and is polyadenylated at the 3' end; (iii) maturation occurs by budding of spherical nucleocapsids 30-35 nm in diameter, with proven or presumed icosahedral symmetry, through cytoplasmic membranes. Where characterized, translation of structural proteins occurs on subgenomic messenger RNA(s); these appear to represent the 3' end of the genome. Nearly all alphavirus species are transmitted by mosquitoes. Transmission also occurs transovarially (Alphavirus) or transplacentally (Rubivirus and Pestivirus). Members of a genus are serologically related, but are not related to members of other genera.
mesh_terms: D000524:Alphavirus / Q000145:classification; D000818:Animals; D000956:Antigens, Viral; D005416:Flavivirus / Q000145:classification; D005814:Genes, Viral; D010576:Pestivirus / Q000145:classification; D013045:Species Specificity; D014035:Togaviridae / Q000145:classification* / Q000378:metabolism / Q000648:ultrastructure; D014036:Togaviridae Infections / Q000635:transmission; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication
chemical_list: D000956:Antigens, Viral; D014764:Viral Proteins