Research Paper Volume 4, Issue 4 pp 270—278

Figure 2. Effect of treatment of A549 cells with 1,25-VD on the level of expression of ATM phosphorylated on Ser1981 in relation to the cell cycle phase. Expression of ATM-S1981^P in A549 cells treated with 2 nM or 10 nM 1,25-VD for 24 or 48 h was detected immunocytochemically using phospho-specific Abs and measured by LSC. The numbers above the arrows indicate the percent reduction in intensity of immunofluorescence of the mean values of cell populations in G₁, S and G₂M phases of the cell cycle in the 1,25-VD-treated cells with respect to the untreated cells (Ctrl) in the same phase of cell cycle. The skewed dash line in Ctrl panel shows the maximal level of fluorescence intensity of the cells stained with isotype control Ab.