Polarity of influenza and vesicular stomatitis virus maturation in MDCK cells: lack of a requirement for glycosylation of viral glycoproteins.

We have investigated whether glycosylation of membrane glycoproteins is a determinant of the site of maturation of enveloped viruses in Madin-Darby canine kidney (MDCK) cells. In MDCK cell monolayers, vesicular stomatitis virus buds exclusively from the basal or lateral plasma membranes and contains a sialylated glycoprotein, whereas influenza virus buds exclusively from the apical plasma membrane and lacks neuraminic acid. In order to study the possible relationship between glycosylation of viral glycoproteins and the budding site, infected MDCK cells were treated with tunicamycin at a concentration that completely inhibits glycosylation of viral glycoproteins and the site of virus maturation was examined by electron microscopy. When tunicamycin-treated monolayers were compared to controls, the polarity in the maturation sites of both viruses was maintained. These results indicate that glycosylation of viral glycoproteins is not required for the determination of the cellular maturation site of these enveloped viruses.