Figure 3.

AI26 suppresses hydrolysis of ADP-ribosylation in cells. A, AI26 treatment suppresses the degradation of ADPR at laser strips. U2OS cells were with or without 10 μm AI26 followed by laser microirradition. ADP-ribosylation at DNA lesions was examined by IF with anti-ADPR antibody. The accumulation kinetics of ADP-ribosylation at DNA lesions was examined in 50 cells (n = 3 independent experiments). The results were summarized as means ± S.D. ***, P < 0.001. The scale bar represents 5 μm. B, AI26 treatment suppresses the digestion of ADPR at oxidative lesions. U2OS cells expressing KillerRed were treated with or without 10 μm AI26 for 1 h, following white light treatment at 25 °C for 10 min. The location of DNA lesions were indicated by IF with anti-KillerRed antibody. The kinetics of ADP-ribosylation at DNA lesions was examined by IF with anti-ADPR antibody. The results are summarized from 50 cells (n = 3 independent experiments) and shown as means ± S.D. ***, P < 0.001. The scale bar represents 5 μm. C, 293T cells were pretreated with or without 10 μm AI26 for 1 h, followed by 0.5 mm H₂O₂ treatment for 5 min at 37 °C. The cellular levels of ADP-ribosylation were examined by dot-blotting assays with anti-ADPR antibody (left panel). The histograms represent the time course results from three independent experiments (right panel). The results were summarized as means ± S.D. ***, P < 0.001. DAPI, 4[prime],6[prime]-diamino-2-phenylindole.