Figure 2.

Mutational analysis of the SARS-CoV-2 spike MPER sequence. Infectivity of the SARS-CoV-2 mutant pseudoviruses in 293T/ACE2 cells (A) or Huh-7 cells (B) was determined by a single-cycle infection assay. (C) Fusogenic activity of the SARS-CoV-2 S mutants was determined by a DSP-based cell fusion assay. In comparison, the luciferase activity (RLU) of the wild-type (WT) was treated as 100% and the relative infection or fusion of a mutant was calculated accordingly. The experiments were repeated three times and data are expressed as the means ± standard deviations (SD). Statistical comparison was conducted by t-test (*, P<0.05; **, P<0.01; ***, P<0.001; ns, not significant).