Fig. 1.

SARS-CoV-2 3CL inhibits IFN-β and ISG mRNA expression. (A-C) Quantitative PCR analysis of IFNB1 (A), IFIT1 (B), and CCL5 (C) mRNA levels in 293 T cells transfected with empty vector or the HA-3CL-expressing plasmid for 24 h followed by infection with SeV for 8 h (top). Expression of the indicated transfected plasmids was detected by immunoblotting with an anti-3CL antibody (1:1000) (below). (D) Quantitative PCR analysis of SeV M mRNA levels in 293T cells transfected with HA-3CL-expressing plasmid or an empty vector and then treated with SeV for the indicated time periods (top). The expression of the indicated transfected plasmids was detected by immunoblotting (below). *P < 0.05; **P < 0.001; ***P < 0.001 (unpaired, two-tailed Student’s t-test). Data are representative of at least three independent experiments.