Figure 7.

Induction of ATM activation in A549 cells following exposure to CS. Photomicrographs of the mock treated cells (A, B) or cells exposed for 20 min to IM16 CS (C, D). The cells were immunocytochemically labeled with phospho-specific ATM-S1981^P antibody, with the secondary antibody fluorescing green (A, C); their DNA was counterstained with DAPI (B, D). In the mock treated sample (A) only the mitotic cell is strongly ATM-S1981P positive. The punctuate staining in two other cells represents labeling of their centrosomes, consistent with data previously reported [14,38,70,71]. The cells exposed to CS exhibited strong and rather uniform IF over the entire nucleus. Nikon Microphot FXA, Obj. 60×