Fig. 8
From: Taxol-Induced Mitotic Block Triggers Rapid Onset of a p53-Independent Apoptotic Pathway
P53-null MEFs fail to arrest in the G1 following the first aberrant mitosis following exposure to taxol.
wt p53-expressing (A–D) and p53-null (E–H) were treated with 250 nM taxol for 0 (A and B), 18 hr (C), or 6 days (D–H; note that cells were refed taxol-containing medium after 3 days to maintain biologically active levels of taxol) and fixed and stained with Hoechst 33342 (A, C, D, E, and H). The open arrowheads in Panel C indicate the size of prophase nuclei and compare this with the size of the mitotic nucleus indicated in the field of the control cells shown in Panel A (corresponding phase Panel B). This size contrasts markedly with the size of the Hoechst stained p53-null prophase nucleus seen after 6 days of taxol treatment indicated by the arrow in Panel E (corresponding phase Panel F to compare with Panel B). The arrow in Panels G and H indicates a cell just beginning chromatin condensation. Bar in Panel H represents 10 µm; magnification is the same for all panels.