The contractile ring constriction defect in Aurora B^AIR-2– but not MKLP1^ZEN-4-inhibited embryos is alleviated by septin^UNC-59 depletion. (A and B) Traces of furrow diameter versus time for individual zen-4(or153ts) and zen-4(or153ts) & unc-59(RNAi) embryos (A) or air-2(207ts) and air-2(207ts) & unc-59(RNAi) embryos (B). For comparison, mean contractile ring diameter is plotted versus time for unc-59(RNAi) and control embryos. The set of 10 control embryos and 14 air-2(or207ts) embryos used to generate the curves in A and B were the same as those used to calculate the rates in Fig. 4 D. (C) For embryos analyzed in parallel in the single experiment shown in A and B (n = 10–19 embryos per condition), the percentages of embryos that completed cytokinesis are shown. (D) Individual traces of furrow diameter versus time after furrow initiation for individual control and cyk-1(RNAi) partial embryos. (E and F) Traces of furrow diameter versus time for individual zen-4(or153ts) and zen-4(or153ts) & cyk-1(RNAi) partial embryos (E) or air-2(or207ts) and air-2(or207ts) & cyk-1(RNAi) partial embryos (F). For comparison, mean contractile ring diameter is plotted versus time for control and cyk-1(RNAi) embryos. The controls for E and F are the same as those shown in Fig. 3. All imaging was performed using the postmeiotic upshift conditions outlined in Fig. 2 A. Furrow diameters were measured in end-on projections of 11-plane z series collected every 20 s. Traces in A, B, E, and F were smoothed by applying a three-point rolling mean. The circles mark the final diameter before regression. The stars at the end of the trace indicate successful completion of cytokinesis. The arrows to the right of the graphs mark the mean maximum ingression for the indicated conditions. The asterisks indicate a significant difference (two-tailed t test, P < 0.05).