FIG. 6.

ATR forms distinct nuclear foci in hypoxic cells. RKO cells were grown on chamber slides and incubated in hypoxic conditions for 18 h. As a positive control RKOs were also treated with APH for 24 h (5 μg ml⁻¹). After treatment, cells were fixed and permeabilized before staining with protein G-purified α-ATR (49). Slides were counterstained with propidium iodide to demonstrate that the foci seen were nuclear.