FIGURE 7.

Combining Taxol and cyclin B1 overexpression blocks slippage and induces mitotic death in DLD-1 cells. A, DLD-1 cells stably expressing DsRed histone H2B and GFP-cyclin B1, the latter under tetracycline control, were synchronized and treated with 1 μm Taxol either alone or in combination with tetracycline (1 μg/μl) for 24 h, and cell extracts were prepared and subjected to immunoblot analysis. GFP-cyclin B1 (80 kDa) was detected using an antibody against cyclin B1. B, DLD-1 cells were synchronized and released into medium containing 1 μg/μl tetracycline to induce GFP-cyclin B1 expression. 1 μm Taxol was added 4.5 h after release, and cells were monitored for 48 h using time-lapse microscopy. The fate profiles of 50 cells are shown in the right panel and compared with DLD-1 cells treated with 1 μm Taxol alone (left panel). Time 0 represents the time of the addition of Taxol. C, tabulation of data from panel B.