FIGURE 3:

(A) Application of the Bax channel blocker iMAC1 just during prolonged prometaphase allows some daughter cells to proliferate even though their mothers spent between 1.5 and 5 h in prometaphase. Asynchronous cultures were treated with nocodazole plus 2.5 μM iMAC1 for 6 h and both drugs washed out. For two 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 (Figure 2A): p = 3.1 × 10^–6. 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). (B) Pancaspase inhibitor allows some daughter cells to proliferate even though their mothers spent between 1.5 and 5.5 h in prometaphase. Asynchronous cultures were treated with 20 μM z-VAD (OMe)-fmk for 12 h to allow drug entry/cleavage. After this agent was washed out, the cultures were treated with nocodazole for 6 h and daughter cells were continuously followed. Significantly more daughters born of mothers spending >1.5 h in prometaphase proliferated relative to the basic experiment (Figure 2A): p = 3.2 × 10^–12. 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).