Growth of enveloped RNA viruses in a line of chinese hamster ovary cells with deficient N-acetylglucosaminyltransferase activity

Abstract

Sindbis and vesicular stomatitis viruses were grown in a line (termed 15B) of Chinese hamster ovary (CHO) cells that is deficient in a specific UDP-N-acetyl-glucosamine:glycoprotein N-acetylglucosaminyltransferase. Both viruses replicated normally in the cell line, but the glycoproteins of the released virus migrated faster on sodium didecyl sulfate-polyacrylamide gels than did glycoproteins of virus grown in parent CHO cells. Digestion of the viral glycoproteins with Pronase followed by gel filtration demonstrated that the glycoproteins with Pronase followed by gel filtration demonstrated that the glycopeptides of Sinbis-15B virus were much smaller than the glycopeptides of Sindbis-CHO virus. In addition, Sindbis-15B viral glycopeptides but not Sindbis-CHO viral glycopeptides contained terminal alpha-mannose residues as shown by their susceptibility to alpha-mannosidase digestion. These findings demonstrate that the oligosaccharide units of the glycoproteins of vesicular stomatitis and Sinbis viruses are altered when the viruses are grown in 15B cells. We conclude that the N-acetylglucosaminyltransferase that is missing in 15B cells normally participates in the biosynthesis of the oligosaccharide units of the viral glycoproteins, and in the absence of this enzyme incomplete oligosaccharide chanis are produced. Viruses released from 15B cells appear to retain full infectivity; Sindbis-15B virus, however, showed a significant decrease in hemagglutination titer compared with that of Sindbis-CHO virus.