FIG 3.

Fusogenic activity is blocked for the HeV F TMD mutants. (A) Vero cells were transfected with the attachment protein WT HeV G and WT HeV F or one of the TMD mutants. Syncytium formation was analyzed at 48 h posttransfection. Images were taken with a Zeiss Axiovert 100 microscope. White arrowheads indicate syncytia. Images are representative. (B) Vero cells were transfected with luciferase, WT HeV G, and WT HeV F DNA or one of the TMD mutants. At 24 h posttransfection, the Vero cells were overlaid with BSR cells. After a 3-h incubation period, the cells were lysed and prepared for luminosity analysis to quantify fusion. Results were normalized to samples transfected with WT HeV F and G. All data are presented as the means ± standard deviations for three independent experiments. Statistical analysis was performed using a two-way analysis of variance with a Bonferroni correction. Asterisks indicate statistical significance compared to values for the WT HeV F (****, P < 0.0001).