FIGURE 10.

Involvement of Atm and DNA-PK in damage-induced 53BP1 foci in cerebellar neurons. A, organotypic cultures derived from various Nbs1 and Atm genotypes were incubated with 2 μg/ml Atm inhibitor KU55933 (ATMi) or 2 μg/ml DNA-PK inhibitor NU7026 (DNA-PKi). The cultures were then treated with 10 Gy of ionizing radiation, fixed at 15 min and 4 and 24 h after irradiation, and reacted with an anti-53BP1 antibody (green). Purkinje neurons were labeled with calbindin D28K (red). The number of 53BP1 foci per nucleus of Purkinje neurons was measured using the Image Pro software in 10–20 nuclei for each treatment/genotype. The experiments were performed in cultures from at least three mice for each genotype. Scale bar = 10 μm. B, higher magnification of WT micrographs show the effect of Atm and DNA-PK inhibitors on the intensity and size of 53BP1 nuclear foci.