Fig. 1: Loss of FTO expression promotes DNA repairs and cell survival following UV exposure.

a Dot-blot detection of the CPDs in genomic DNA of HeLa cells upon UVC irradiation. Methylene blue showed the amount of DNA loaded onto the membrane. b Quantification of CPD levels. Data were normalized to the non-irradiated controls (N = 9 per group) and analyzed using two-way ANOVA with Dunnett’s multiple comparison test (*WT vs KO.1 and ^#WT vs KO.2). c WT or FTO KO HeLa cells were pre-treated with BrdU, irradiated with 100 J of UVC, and allowed to recover for 30 min and 6 h. Cells were fixed and stained with the DNA double-strand break marker γH2A.X (green) and DAPI (blue). Scale bar, 20 μm. d Quantification of γH2A.X levels. Data were normalized to the WT group (N = 4 biological replicates; WT-30 min = 176 cells; KO.1-30 min = 301 cells; KO.2–30 min = 291 cells; WT-6 h = 198 cells; KO.1–6 h = 266 cells; KO.2-6 h = 272 cells) and analyzed using one-way ANOVA with Dunnett’s multiple comparison test. e Same experiment as c, but cells were lyzed and subjected to western blotting analysis with antibodies against γH2A.X, FTO and α-tubulin. f Quantification of γH2A.X levels after data were normalized to the 6 h—WT group (N = 5 per group). Data were analyzed using two-way ANOVA with Sidak’s multiple comparison tests. g WT or FTO KO HeLa cells were subjected to UVC irradiation at the indicated dosages. Colonies of surviving cells were stained with crystal violet 14 days post-UVC exposure. h The percentage of cell survival was determined by quantifying the number of colonies and normalizing them to the non-irradiated control groups (N = 4–7 per group). Data were analyzed using two-way ANOVA with Tukey’s multiple comparison test (*WT vs KO.1 and ^#WT vs KO.2). All data are represented as mean ± SEM. Source data are provided as a Source Data file.