Fig. 7: FTO is a direct target of PARP1.

a Recombinant His-FTO proteins are PARylated in vitro. b Endogenous FTO protein is PARylated in response to UVC irradiation in HeLa cells. c Quantification of FTO PARylation levels. Data were normalized and compared to non-irradiated control groups using a two-tailed Mann-Whitney test (0 min, N = 7; 1 min, N = 5; 4 min, N = 7; 10 min, N = 6). d Time course of FTO-PARP1 proximal interaction in WT HeLa cells upon UVC irradiation. Scale bar, 20 μm. e Quantification of the number of PLA puncta per nucleus (Ctrl, N = 194 cells; UV-1 min, N = 154 cells; UV-4 min, N = 153 cells; UV-10 min, N = 93 cells). Data were analyzed using one-way ANOVA with Tukey’s multiple comparison test. f Time course of FTO-PARP1 proximal interaction determined by BAR assays. g Quantification of biotinylated PARP1. Data were normalized and compared to non-irradiated control groups using a two-tailed Mann-Whitney test (0 min, N = 4; 1 min, N = 3; 4 min, N = 4; 10 min, N = 3). All data represent mean ± SEM. h Recombinant Flag-PARP1 was incubated with a combination of NAD⁺, Olaparib or His-FTO for 30 min at 30 °C, followed by Ni²⁺-Sepharose pull-down. In condition a, Olaparib was added at the end of 30 min incubation to stop the PARylation reaction. In condition b, His-FTO was added after the PARylation reaction. Representative blots from 4 independent experiments are shown. i A schematic diagram of the working model. We propose that FTO maintains the clustering PARP1 and dampens its catalytic activity in the nucleolus. Upon UV exposure, PARP1 dissociates from FTO, allowing it to be recruited to the sites of DNA damage. Loss of FTO expression enhances PARP1 enzymatic activity and the rate of PARP1 recruitment to DNA damage sites, thereby accelerating DNA repair and promoting cell survival. Created in BioRender. Anggono, V. (2025) https://BioRender.com/r35n837. Source data are provided as a Source Data file.