FIGURE 2.

The NER-dependent recruitment of DDR factors mainly depends on ATM activity. A, TIG-120 or AT2KY cells were arrested in G₀ phase and locally irradiated with 40 J/m² of UV through an isopore membrane filter (pore size, 8 μm). After 1-h incubation, the cells were fixed and immunostained with the indicated antibodies. Note that AT2KY cells were treated with 100 μm LY294002 for 30 min before UV irradiation and during post-UV 1-h incubation. B, G₀-arrested TIG-120 cells were pretreated with or without either 10 μm KU-55933 (ATMi) or 10 μm NU7026 (DNA-PKi) for 30 min. The cells were irradiated with 20 J/m² of UV and incubated with or without each inhibitor for 1–4 h before cell lysis. The phosphorylation of ATM and Chk2 was analyzed by Western blotting with phospho-specific antibodies to Ser¹⁹⁸¹ and Thr⁶⁸, respectively. C, G₀-arrested TIG-120 cells were pretreated with ATMi or DNA-PKi as described above and locally irradiated with 40 J/m² of UV through an isopore membrane filter (pore size, 5 μm). After 1-h incubation with each inhibitor, the cells were co-immunostained with anti-MRE11 and anti-CPD antibodies.