FIG 1.

Glycoproteins gHgL and gB can trigger fusion of epithelial cells when expressed in trans. (A to C) AGS cells were transfected with plasmids expressing gHgL and gB in cis or with gHgL alone or gB alone and overlaid with AGS (A), CHO (B), or HaCat (C) cells transfected with empty vector, gHgL, or gB as indicated. Fusion was measured 24 h after cells were overlaid by staining with monoclonal antibody CL55 to gB and counting the percentage of stained cells that contained 4 or more nuclei. Fusion in trans was expressed as the percentage of fusion in cis. The values for fusion in cis were 24% ± 1.8% (A), 28% ± 5.3% (B), and 25% ± 2.7% (C). (D) CHO cells were transfected with a plasmid expressing luciferase under the control of a T7 promoter and with either empty vector, gHgL and gB in cis, or gHgL or gB alone and overlaid with 293T14 cells transfected with empty vector or gB as indicated. Fusion was measured in terms of luciferase activity. The error bars are the standard deviations from 4 experiments.