Figure 5

XRCC1, but not WRN translocation from nucleoli, is partially dependent on PARP1 enzymatic activity. (A) Quantitative analysis of subnuclear WRN localization using automated image analysis as described in the ‘material and methods’ section. Cells were treated with H₂O₂ and the PARP inhibitor olaparib as indicated and subjected to immunofluorescence staining for WRN and fibrillarin. Data represent means ± SEM of three independent experiments. Statistical analysis was performed by 2-way ANOVA testing. (B) Quantitative analysis of subnuclear XRCC1 localization. Samples were stained for XRCC1 and fibrillarin, and data presented as described in A. (C) HeLa PARP1 KO cells were reconstituted with PARP1-WT or the mono-ADP-transferase mutant PARP1-E988K, left untreated or treated with 500 µM H₂O₂ for 2 h, and subjected to co-immunofluorescence staining for XRCC1 and fibrillarin and subsequent quadruple-color microscopy. Representative images are shown in Suppl. Fig. 10. Shown is the quantitative analysis of subnuclear XRCC1 localization using automated image analysis. Data represent means ± SEM of four independent experiments. Statistical analysis was performed by 2-way ANOVA testing.