FIG. 2.
GS enhances membrane fusion induced by GNJ. BHK-21 cells were transfected with plasmids encoding GSHA (A), GSHA and GNJ (B), or GNJ alone (C). At 36 h posttransfection, cells were fixed with 3% paraformaldehyde and stained. The cells were not pretreated with fusion medium, and therefore, the pH was maintained at 7.2 to 7.4 throughout the incubation period. Cells expressing GNJ and GNJ plus GSHA were probed with monoclonal antibody VIII, which is specific for the GNJ glycoprotein. Cells expressing GSHA were stained with the 12CA5 monoclonal antibody, which is specific for the HA epitope. Representative epifluorescence and phase-contrast micrographs of the cells are shown.