Extended data Fig 6. ISG induction by ionizing radiation is abrogated in non-cycling cells.

(a) Experimental setup: To arrest cells in G0, serum was withdrawn 24 h before transfection with Herring testis DNA (HT-DNA), and supernatant harvested 24 h later. (b) CCL5 production in response to transfected HT-DNA was equivalent between cycling and serum starved MEFs. Mean ± SEM, n=2 independent experiments. (c) Schematic of experimental protocol. (d) Cycling and G0-arrested cells exhibit the same level of DNA damage as measured by γH2AX foci formation per cell. Representative images; scale bar 10 μm. Quantifications shown in Fig 4d. (e) No significant increase in ISG transcripts, IFIT1, IFIT3, ISG15, CXCL10 and OAS1A, for cells arrested in G0 after serum starvation (experimental setup as in c). Transcript levels were normalised to HPRT. Mean ± SEM. One-way ANOVA, 2 degrees of freedom, n=3 independent experiments; ns = not significant. Compare to Extended data Fig 1g, showing data for matched cycling cells assessed concurrently.