Fig. 4

The spindle poles act as brakes during meiotic chromosome segregation. a Schematics and still images from live imaging of control not ablated (top), control ablated (second from top), central spindle (second from bottom) and spindle pole (bottom) laser-mediated ablation in GFP-tagged α-tubulin and mCherry-tagged histone H2B expressing fertilized oocytes. White arrowheads indicate the ablation events. Scale bar, 2 µm. b Distance between the centroid of each set of segregating chromosomes over time after anaphase onset in the indicated conditions. Error bars represent the SEM. Thick and thin vertical dashed lines represent the average and minimum/maximum times of ablation respectively. Background colors represent average duration of anaphase A (light orange) and B (light blue) respectively. (One-way ANOVA: control ablation at 180 s, p = 0.9297; central spindle at 180 s, p = 0.9007; Spindle pole at 180 s, p = 0.9924; control ablation at 300 s, p = 0.9951; central spindle at 300 s, p = 0.0045; spindle pole at 300 s, p = 0.1771) c Still images from live imaging of fertilized oocytes expressing GFP-tagged α-tubulin and mCherry-tagged histone H2B in the indicated conditions. Timings from anaphase onset are indicated at the bottom of each frame. Scale bar, 5 µm. d Distance between the centroid of each set of segregating chromosomes over time after anaphase onset in the indicated conditions. Tracking was performed until the anaphase spindle broke apart at the end of polar body extrusion. Error bars represent the SEM. Background colors represent average duration of anaphase A (light orange) and B (light blue) respectively. (One-way ANOVA: aspm-1 ^Asp (RNAi) at 180 s, p = 0.2281; aspm-1 ^Asp  + lin-5 ^NuMA (RNAi) at 180 s, p = 0.0910; aspm-1 ^Asp  + dhc-1 ^dynein (RNAi) at 180 s, p = 0.6103; aspm-1 ^Asp (RNAi) at 240 s, p = 0.0018; aspm-1 ^Asp  + lin-5 ^NuMA (RNAi) at 240 s, p = 0.0015; aspm-1 ^Asp  + dhc-1 ^dynein (RNAi) at 240 s, p = 0.0077) e Still images from live imaging of fertilized oocytes expressing GFP-tagged β-tubulin and mCherry-tagged histone H2B in the indicated conditions. Timings from anaphase onset are indicated at the bottom of each frame. Scale bar, 5 µm. f Distance between the centroid of each set of segregating chromosomes over time after anaphase onset in the indicated conditions. Tracking was performed until the anaphase spindle broke apart at the end of polar body extrusion. Error bars represent the SEM. Background colors represent average duration of anaphase A (light orange) and B (light blue) respectively. (One-way ANOVA: dhc-1(or195ts), 16 °C at 180 s, p = 0.0926; dhc-1(or195ts), 26 °C at 180 s, p = 0.9999; aspm-1 ^Asp  + lin-5 ^NuMA (RNAi) + dhc-1(or195ts), 26 °C at 180 s, p = 0.4751; dhc-1(or195ts), 16 °C at 240 s, p = 0.0009; dhc-1(or195ts), 26 °C at 240 s, p = 0.9853; aspm-1 ^Asp  + lin-5 ^NuMA (RNAi) + dhc-1(or195ts), 26 °C at 240 s not available)