Figure 2. Cytoplasmic nucleosome production in DMBA-treated cells is independent of STING.

(a) Fluorescence microscopy analysis of anti-dsDNA staining (a,b) and fluorescent in situ hybridization (FISH) with mouse centromere probe (c,d) in WT, TKO, STKO and SKO MEFs treated with DMBA at 20 µg ml⁻¹ or DMSO as control for 48 h. Representative images are shown at × 1,260; bar size, 10 µm (a,c), and ratio of cytoplasm to nucleus anti-dsDNA pixels from a and FISH pixels from c was quantitated using Leica LAS AF software (b,d). (e) Immunoblot analysis of histone H3 in cytoplasmic extraction from MEFs treated with DMBA same as in a or ultraviolet at 120 mJ cm⁻² followed by 24-h incubation (also see Supplementary Fig. 10). (f) Electron microscopy analysis of histone H3 and dsDNA gold staining in WT and TKO MEFs treated with DMBA same as in a. Arrows indicate gold particles in cytoplasm. Images were shown at original magnification, × 100,000; bar size, 100 nm. Data are representative of at least two independent experiments. Error bars indicate s.d. *P < 0.05, ***P < 0.001, Student’s t-test.