FIG 6.

The N4 L257A mutant is able to fuse alone at 42°C. (A) Representative images of HEK 293T cells transfected with wild-type NiV F or the L257A mutant, in the absence of NiV G, and fused at 42°C. (B) Number of nuclei per syncytium yielded by wild-type F versus the L257A mutant. A total of ≥10 syncytia/transfected well were analyzed for both wild-type F and the L247A mutant alone. Data are averages and SDs from at least 3 independent experiments. Statistically significant differences, as determined by two-sample, two-tailed t tests, are marked with an asterisk: *, P ≤ 0.05 (C) Dual split protein fusion assay performed at 42°C with 36-h effector and target cell overlay. RLU were normalized to WT F alone. Data are averages and SDs from 4 independent experiments. Statistically significant differences, as determined by one-sample, two-tailed t test, are marked with asterisks: **, P ≤ 0.01.