Fig. 7. ORF6 inhibits STAT1 nuclear translocation via its C-terminus.

a, b Effect of SARS-CoV-2 ORF6 and its mutants on IFN-β-induced ISRE- and ISG56-promoter activation. HEK293T cells were transfected with an ISRE reporter plasmid (a) or an ISG56 reporter plasmid (b), along with a control plasmid or plasmids expressing wildtype or indicated SARS-CoV-2 ORF6 variants. At 24 h post-transfection, cells were treated with 800 U/ml IFN-β for 12 h, and luciferase activity was measured. Protein expression levels were detected by Western blot analyses. c Effect of SARS-CoV-2 ORF6 and its variants on IFN-β-induced STAT1 nuclear translocation. Vero cells were transfected with plasmids expressing wildtype ORF6 or indicated ORF6 variants. At 24 h post-transfection, cells were treated with 1000 U/ml of human IFN-β for 30 min and stained with indicated antibodies. Merge 1 and Merge 2 indicate the merged red and green channels and the merged red, green, and blue channels, respectively. Scale bar, 10 μm. All experiments were done at least twice, and one representative is shown. Error bars indicate SD of technical triplicates, **P < 0.01, and ***P < 0.001, ns not significant, two-tailed Student’s t-test. Source data are provided as a Source Data file.