Fig. 3

SARS-CoV-2 NSP13 suppresses type I and II IFN signaling by preventing STAT1 phosphorylation. HEK293T cells were transfected with an expression plasmid for V5-tagged NSP13. A At 48 h post transfection, cells were stimulated by 1000 U/mL of IFN-β. B Cells were treated with 100 ng/mL of IFN-γ. At 10- and 20-min post IFN treatment, cell lysates were collected and analyzed by Western blotting with the indicated antibodies. C Experiment in A was repeated with FLAG-tagged NSP13. At 30 and 45 min post IFN-β treatment, cell lysates were collected and analyzed by Western blotting. Relative ratios of pSTAT1 versus total STAT1, pSTAT2 versus total STAT2 and pJAK1 versus total JAK1 were determined by densitometry and are indicated below the blots. pSTAT1: phospho-STAT1. pSTAT2: phospho-STAT2. pJAK1: phospho-JAK1. Results were representative of three independent experiments