Survivin-depleted cells fail to complete cytokinesis. (A) The mitotic index of Survivin^OFF cells is increased for both KO1 and KO2 relative to wild-type (WT) DT40. (B) Shutoff of Survivin expression leads to an increase in multinucleated (primarily binucleated) cells. Values for cells grown in doxycycline are shown as striped bars. Error bars indicate SD. (C) Selected frames from videos of Survivin^ON and Survivin^OFF cells. Merged images show differential interference contrast (red) and histone H2B-mRFP (green), with H2B-mRFP also shown in grayscale. Time is given in hours/minutes. A control Survivin^ON cell (top) completes mitosis normally. The Survivin^OFF cell achieves a metaphase alignment (0:25) but exhibits lagging chromosomes in anaphase, and cytokinesis ultimately fails. Bar, 5 μm. (D) Synchronization of DT40 cells by centrifugal elutriation. (E) Cells harvested later in the cell cycle die before those harvested earlier in the cell cycle. (F) Cells harvested later in the cell cycle fail cytokinesis before those harvested earlier in the cell cycle.