Fig 4.
Infectivity and thermolysin cleavage of the F535R fusion loop mutant. (A) Infectivity. Equivalent volumes of culture supernatants containing VSV pseudovirions bearing wild-type or F535R EBOV GPΔ were used to determine titers on Vero cells by serial dilution (triplicate samples). Infected cells were scored by visual inspection for GFP expression. Titers of wild-type and F535R virus were 4.30 × 107 IU/ml and 3.75 × 105 IU/ml, respectively. The data are from one experiment performed in triplicate. Bars indicate SD. (B) Thermolysin cleavage. WT or F535R GPΔ Ecto proteins (0.1 mg/ml) were treated with thermolysin (Th; 0.1 mg/ml) (+) or buffer (−) as described in Materials and Methods and analyzed by SDS-PAGE and Western blotting for GP1.