Fig. 1

Influenza virus triggers mtDNA release. a HEK293FT cells were subjected to digitonin fractionation as described in the Methods and pellets (Pel) or cytosolic extracts (Cyt) were analyzed by western blotting using the indicated antibodies. b HEK293FT cells were infected with PR8 virus at indicated MOIs. Cytosolic mtDNA was assessed by quantitative PCR. c HEK293FT cells were infected with PR8 virus at MOI of 10. Cell lysates were collected at indicated time points and analyzed by immunoblotting with indicated antibodies (left panel). Cytosolic mtDNA was assessed by quantitative PCR (right panel). d HEK293FT were infected with PR8 virus. Cells were collected at 24 h post infection, and intracellularly stained with dsDNA-specific antibody (35I9 DNA). e STING-A549 cells were infected with PR8 virus. At indicated time points, cells were stained with anti-dsDNA (AC-30-10) and anti-Tom20 antibodies and analyzed by confocal microscopy. Scale bars, 10 μm. f HEK293FT cells were infected with WT or ΔNS1 influenza virus at MOI of 10. Cytosolic mtDNA was assessed by quantitative PCR. g HEK293FT cells were transfected with the expression plasmid encoding EGFP or Flag-tagged NS1 protein. Twenty-four hours after transfection, the cells were infected with ΔNS1 influenza virus for 24 h. Cytosolic mtDNA was assessed by quantitative PCR. h WT or MAVS KO HEK293FT cells were infected with ΔNS1 influenza virus for 24 h. Cell lysates were collected and analyzed by immunoblot using indicated antibodies (left panel). Cytosolic mtDNA was assessed by quantitative PCR (right panel). i MAVS KO MEFs, or MAVS KO MEFs re-introduced full-length MAVS (MAVS KO (+MAVS)) were infected with ΔNS1 influenza virus for 24 h. Cytosolic mtDNA was assessed by quantitative PCR. j HEK293FT cells transfected with siRNA targeting Bax or control siRNA were infected with ΔNS1 influenza virus for 24 h. Cytosolic mtDNA was assessed by quantitative PCR. These data are from three independent experiments (b, c, f–j; mean ± s.e.m.). *P < 0.05, **P < 0.01, ***P < 0.001; (one-way ANOVA and Tukey’s test). Source data are provided as a Source Data file