FIGURE 2:

(A) Relationship between prometaphase duration and daughter cell proliferation under standard culture conditions—the “basic” experiment (redrawn from Figure 1B of Uetake and Sluder [2010]). Asynchronous cultures were treated with nocodazole for 6 h and entry of individual cells into mitosis followed. After drug washout, daughters of previously followed mothers were continuously followed. Each vertical bar represents a daughter cell remaining in the field of view and the height of the bar indicates the prometaphase duration for its mother cell. The bars are ordered by the duration of prometaphase for the mother cells. Daughters that proliferated are shown as light-colored bars, and those that arrested in G1 are shown as dark colored bars. The vertical dashed line indicates the prometaphase duration of the mother cells (90 min) beyond which all daughter cells arrested in G1. (B) Partial inhibition of MCL1 activity during prometaphase reduces the temporal tolerance for prolonged prometaphase. Asynchronous cultures were treated with nocodazole plus MIM1 for 6 h and both drugs washed out. Significantly fewer daughters born of mothers spending <1.5 h in prometaphase proliferated relative to the basic experiment (A): p = 0.0019. For the daughters born of mothers spending >1.5 h in prometaphase, there was no significant increase in the proportion of cells that proliferated (p = 1.0). (C) Knockdown of the F-box protein FBW7 allows some daughter cells to proliferate even though their mothers spent up to 4.6 h in prometaphase. Forty-eight hours after siRNA transfection, asynchronous cultures were treated with nocodazole for 6 h and the progeny of individual mother cell were continuously followed. For three pairs of daughter cells born of mothers spending >1.5 h in prometaphase, one daughter proliferated while its sister arrested. Significantly more daughters born of mothers spending >1.5 h in prometaphase proliferated relative to the basic experiment (A): p = 0.00012. For the daughters born of mothers spending <1.5 h in prometaphase, there was no significant decrease in the proportion of cells that proliferated (p = 1.0).