The Proteins and RNAs of St. Abb's Head Virus, a Scottish Uukuvirus

The proteins and RNAs of St. Abb's Head virus have been analysed, and were found to be characteristic of the Uukuvirus genus of the family Bunyaviridae. Two glycoproteins, G1 and G2 (mol. wt. 62K and 75K), and a nucleocapsid protein, N (mol. wt. 25K), were detected in infected cells by immunoprecipitation; the synthesis of N preceded the synthesis of G1 and G2. The glycoproteins were relatively cysteine-rich compared to the N protein, and the unglycosylated forms of G1 and G2 (using the inhibitor tunicamycin) had a mol. wt. of about 58K. Translation in vitro of mRNA from infected cells gave two immunoprecipitable products which are thought to be equivalent to N and G1/G2. Three RNA species were found in St. Abb's Head virus nucleocapsids, and were estimated to be 8500 bases (L), 3600 bases (M) and 1900 bases (S) in length. At least one additional virus-specific RNA species was detected in infected cells. The similarity between the proteins and RNAs of St. Abb's Head virus and Uukuniemi virus (the prototype of the genus) is discussed.