Fig. 2. cGAS conjugation enhances cGAMP production and anti-phage immunity in vivo.
a–c, Viral titre of phage T4 (a), T6 (b) and lambda (c) after infection of bacterial strains with the wild-type operon from E. coli (CBASS), no operon (empty vector) or the indicated point mutations. Data are mean ± s.d. of n = 3 independent experiments with individual points overlaid. d, Viral titre of phage T2 after infection in bacterial strains harbouring the wild-type V. cholerae CBASS operon, no operon (empty vector) or the indicated point mutations. Data are mean ± s.d. of n = 4 independent experiments with individual points overlaid. e, E. coli harbouring the indicated CBASS operon was infected by the phage T4 at a multiplicity of infection of approximately 10. CapV in the CBASS operon was inactivated by a mutation in the active site (S60A) to avoid cell death from CBASS signalling. Samples from each bacterial culture were collected 60 min after infection, snap frozen and lysed by heating. Clarified lysates were incubated with THP1 Lucia ISG cells, which express a luciferase (Lucia) reporter gene under the control of an IRF-inducible promoter. Luminescence signal was measured and converted to cGAMP concentrations using a cGAMP standard curve. Data are mean ± s.d. of n = 3 technical replicates and is representative of two independent experiments.