Fig. 5. Colocalisation of p21-GFP with DNA repair proteins recruited to DNA-damage sites. HeLa cells expressing p21-GFP were locally irradiated with UV-C (10 J/m²) through 3 µm pores. After 30 minutes, cells were extracted in situ and fixed for determination of chromatin-bound p21-GFP and immunofluorescence staining of DNA repair proteins. (A) Confocal sections of p21-GFP (green) and pol (red) fluorescence signals are displayed together with the merged image also showing DNA counterstaining with Hoechst 33258 (blue). (B) confocal sections showing the single and merged images of p21-GFP (green), and XPG (red) at the irradiated sites. DNA was counterstained with Hoechst 33258 (blue). (C) Confocal sections showing the recruitment of p21-GFP (green) and CAF-1 (red), and DNA counterstaining (blue). Bars, 5 µm.