Figure 1

H₂O₂-induced WRN translocation from nucleoli to the nucleoplasm is PARP1-dependent. (A) Western blot verifying the PARP1 KO on the protein level of HeLa cells used in this study and as described previously¹⁹. Full-length blots are shown in Suppl. Fig. 13. (B) HeLa WT and PARP1 KO cells were left untreated or treated with 500 µM H₂O₂ for periods as indicated. Samples were then subjected to immunofluorescence staining for WRN and PAR and analyzed by confocal microscopy. Representative images of three independent experiments are shown. The second column displays magnified sections of images of the first column. Brightness and contrast were adjusted for better visibility. Scale bars represent 20 µm. (C) Co-staining of WRN and the nucleolar marker protein nucleolin verifying the nucleolar localization of WRN under untreated conditions. (D) Categorized image analysis of WRN nucleolar localization as described in the ‘material and methods’ section of three independent experiments. Cells were treated with H₂O₂ for 2 h. Data represent means ± SEM. Statistical analysis was performed by a Chi-square test.