Figure 1: A role for STING but not cGAS in innate antiviral responses against RNA viruses.

(a–d) MEFs from C57BL/6, cGAS^−/− and STING^gt/gt mice were infected with (a) NDV (MOI 1), (b) SeV (MOI 0.1), (d) VSV (MOI 0.01) or (c) transfected with poly(I:C; 2 μg ml⁻¹). Supernatants were isolated 16–20 h later and levels of type I interferon (IFN) and viral titre were quantified by interferon bioassay and end point titration, respectively. Data are presented as means of four biological replicates +/− s.d. (e) THP1 cells deficient in β2 microglobulin (B2M KO), cGAS (cGAS KO), or STING (STING KO) were infected with IAV (MOI 10). Supernatants were harvested 16 h later and analysed for interferon-α/-β bioactivity. Data are presented as means of four biological replicated ±s.d. (f) MAVS-deficient THP1 cells were infected with SeV, IAV or NDV for 8 h, and lysates were analysed for levels of STING dimers by western blotting using non-reduced SDS-PAGE. (g) MAVS-deficient THP1 cells transduced with Control, cGAS or STING shRNA were infected with IAV and RNA collected at 5 h and 20 h post infection were analysed for levels of interferon-β and CXCL10 mRNA, respectively, by RT–qPCR. (h) THP1 cells were infected with IAV for 60 min and stained for hemagglutinin (HA; red), STING (green) and DAPI (blue) and analysed by confocal microscopy. (i) Immunoprecipitation of hemagglutinin was performed on lysates from THP1 cells infected with IAV for 1 h. The precipitate was immunoblotted for STING. (j) N-terminal HA2 sequences from IAV strains and influenza B Virus. (k) THP1 cell lysates were mixed with recombinant biotin-labelled FP. Eluate from streptavidin beads was analysed by immunoblotting. (l) THP1 cells deficient in B2M KO and STING KO THP1 cells were pretreated with 5 μM of FP and infected with IAV. Supernatants were collected 16 h later and analysed for interferon-α/-β bioactivity. All experiments were performed at least three times with similar results. *P<0.05 by Mann–Whitney compared-ranks test.