Structural Polypeptides of Coronavirus IBV

Abstract

Avian infectious bronchitis virus (IBV) was grown and radiolabelled with 35S-methionine, 3H-leucine and 3H-glucosamine in de-embryonated chicken eggs. Approximately 12 different polypeptides were clearly detected by SDS-polyacrylamide gel electrophoresis of virus preparations. Growth of IBV in chorioallantoic membrane cells labelled with 35S-methionine indicated that most of these polypeptides, and additional ones, some of which were glycosylated, were host components. Five polypeptides appeared to be virus-coded, with apparent mol. wt. of 94 x 10(3), 84 x 10(3), 54 x 10(3), 30 x 10(3) and 28 x 10(3). Four of these, p94, p84, p30 and p28, were glycosylated. The virion spikes appeared to be composed of p94 and p84, while p30 and p28 were partially embedded in the virion membrane. By analogy with other reports, p54 is the nucleocapsid polypeptide.