FIGURE 2.
Knockdown of ICADL, but not of ICADS, impedes stage II apoptotic nuclear morphology in SK-N-AS cells treated with STP. A, schematic illustrating ICADL and ICADS mRNAs showing the position against which the different siRNAs were designed. The numbers pictured in each mRNA (1-6, empty segments) represent the exons. The intron 5 (filled segment) is only preserved in ICADS mRNA. The specific siRNAs designed against ICADS are complementary to intron 5, whereas the ICADL siRNA is complementary to the exon-5/exon-6 junction. The start and stop codons are indicated in both mRNAs. B, SK-N-AS cells were transfected with NR siRNA, ICADL siRNA, or three different ICADS siRNAs (1-3). Total protein extracts of the different conditions were obtained, and ICADL and ICADS protein levels (upper panel) were analyzed by Western blot analysis 5 days after transfection. The membrane was reprobed with anti-DFF40/CAD antibody (lower panel). C, SK-N-AS cells transfected with NR siRNA, ICADL siRNA, or ICADS siRNA number 1 were treated with 1 μm STP for 24 h or left untreated (Control), and nuclear morphology was analyzed by staining the nuclei with Hoechst 33258. The right panels are magnifications of the insets in the center panels. Scale bars = 40 μm.