Glycoproteins of bovine viral diarrhoea-mucosal disease virus in infected bovine cells.

Bovine cell cultures infected with bovine viral diarrhoea-mucosal disease (BVD) virus were radiolabelled with L-[35S]methionine or D-[2-3H]mannose followed by analysis of the labelled polypeptides by radioimmunoprecipitation and polyacrylamide gel electrophoresis in one and two dimensions. Six glycoproteins were detected in infected cells. Two abundant species had Mr of 48K and 56K to 58K while the less abundant species had Mr of 118K, 75K, 65K and 25K. When cells were radiolabelled with L-[35S]methionine in the presence of tunicamycin 56K to 58K migrated with apparent masses of 54K (a minor species) and 48K to 50K (the major molecular species) in PAGE. Endoglycosidase F digestion of virus-induced polypeptides caused a 4K to 6K reduction in the apparent molecular mass of 56K to 58K yielding a single 52K digested product, indicating that the heterogeneity of 56K to 58K was due to differences in the oligosaccharide moieties. Tunicamycin caused a drastic reduction in the yield of infectious virus indicating that the carbohydrate moieties serve a critical role in the infectious cycle of BVD virus.