ANALYSIS OF RUBELLA-VIRUS E1 GLYCOSYLATION MUTANTS EXPRESSED IN COS CELLS

cDNA clones encoding the envelope glycoprotein El of rubella virus (RV) were altered by site-directed mutagenesis at consensus sites for addition of N-linked glycans. The resulting plasmids were introduced into COS cells and the mutant E1 proteins were analyzed by indirect immunofluorescence, radioimmunoprecipitation, and immunoblotting. We found that RV El contains three N-linked oligosaccharides, each approximately 2 kDa in size. Although lack of glycosylation did not appear to affect targeting of Et to the Golgi region, mutants lacking N-linked glycans at Asn 177 and Asn 209 failed to bind anti-El antibodies under nonreducing conditions. Our results suggest that glycosylation may be important for expression of important immunologic epitopes on RV E1. © 1991.