Fig. 7. Immunofluorescence microscopy of Fas-treated HeLa cells in the presence of z-DEVD-FMK. Cells grown on glass coverslips were treated with Fas antibody and PD 98059 for 24 hours in the presence of 100 µM (A-D) or 30 µM (E and F) z-DEVD-FMK and stained with NuMA (A and E) or lamin A/C primary antibody (C) and with FITC-conjugated goat-anti-mouse secondary antibody. Samples were counterstained for DNA with Hoechst (B, C and F). Note the atypical apoptotic cells (arrows) in the presence of 100 µM z-DEVD-FMK, in which chromatin is partially condenced and the nuclear outer border is convoluted. These cells are negative for NuMA (A) and lamin A/C (C). In the presence of 30 µM z-DEVD-FMK, chromatin is slightly condenced in atypical apoptotic cells (F, arrows) and the nuclei have lost their normal round shape. NuMA staining shows highly irregular distribution inside the nucleus (E). Bar 10 µm.