Sindbis envelope proteins as endogenous acceptors in reactions of guanosine diphosphate-[14C]Mannose with preparations of infected chicken embryo fibroblasts.

Preparations of Sindbis-infected chicken embryo fibroblasts incubated with GDP-[14C]mannose and UDP-N-acetylglucosamine catalyze the glycosylation of endogenous phospholipids and membrane-associated proteins. The proteins are identified as the viral envelope proteins by precipitation with anti-Sindbis antiserum, by comparison with authentic virion glycoproteins on sodium dodecyl sulfate-poly-acrylamide gel electrophoresis, and by comparison of the glycopeptides of the membrane-associated glycoproteins with the glycopeptides from Sindbis virions on gel filtration chromatography. Our results indicate that glycophospholipid participates in the mannosylation of the viral proteins since an inhibitor of oligosaccharide-lipid synthesis also inhibits the labeling of the glycoproteins.