Fig. 4.

. SARS-CoV-2 3CL targets IRF3 to regulate the RIG-I signalling pathway. (A) Immunoblot analysis of the indicated proteins in 293T cells transfected with HA-3CL or an empty vector and then infected with SeV for 6 h, followed by nuclear-cytoplasm extraction. The expression levels of the indicated proteins were analysed with the indicated antibodies (left). Relative quantification analysis of IRF3 and p65 (right). (B) Immunoblot analysis of lysates of 293T cells transfected with Flag-RIG-I, Flag-MAVS, Flag-TBK1, Flag-p65, or Flag-IRF3, along with HA-3CL or an empty vector for 24 h. The expression levels of the indicated proteins were analysed with the indicated antibodies (left). Relative quantification analysis of RIG-I, MAVS, TBK1, p65 and IRF3 (right). *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.