Figure 2

DNA damage activation at telomeres. BJ-EHLT fibroblasts were treated for 24 hrs with compound 1 and the indicated ligands at the doses 0.1 (light-grey bars) and 0.5 μM (dark-grey bars). Cells were processed for immunofluorescence (IF) using antibodies against γ-H2AX and TRF1 to mark DNA damage and telomeres respectively. Percentages of γ-H2AX- (A) and TIF-positive (B) treated and untreated cells are reported in the histograms. (C) Mean number of TIFs in the indicated samples. Cells with four or more γ-H2AX/TRF1 foci were scored as TIF positive. Error bars indicate the standard deviation. (D) Representative images of IF of untreated and 1, 3, 6 and 8-treated BJ-EHLT cells. Enlarged views of TIFs are reported on the right of the merged images. The images were acquired with a Leica Deconvolution microscope (magnification 100x). (E) Cells treated as in (A) were processed for IF of γ-H2AX and PCNA to mark replicating cells. Percentage of γ-H2AX+/PCNA- or γ-H2AX+/PCNA + nuclei in the indicated samples are reported in the histograms. The mean of three independent experiments with comparable results is shown.