Fig. 3

Activation of cGAS pathway in syncytia induced by SARS-CoV-2 infection and Spike-ACE2 expression. a and b Channeled images (a) and line scan analysis (b) showed cGAS and IRF3 were co-localized with micronuclei. Scale bars: 1 μm for the inserts in the lower left corner; 20 μm for full images. c Quantification of micronuclei positive in cGAS (+) and IRF3 (+) in Hela-ACE2 cells transfected with spike protein. d The relative mRNA level of IFIT2, IFNB1, CCL5 and CXCL10, respectively in Hela-ACE2 cells 24 h after transfection. *P < 0.05; **P < 0.01. e and f The expression of cGAS, STING, IRF3 and their phosphorylated form were increased upon expression of spike protein analyzed by Western blot (e) and quantification (f). All results were normalized by the expression of β-actin. Data are mean ± SD of triple quantification. *P < 0.05; **P < 0.01; ***P < 0.001