Fig. 4

Bivalents experience greater centromere–kinetochore separation on the cortical side of the spindle. a Schematic to show the location of the probes used and the measurement of central and cortical centromere–kinetochore (C-KT) separation. A representative image to show centromeres (Maj.Sat.-mClover, green), kinetochores (Spc24-mCherry, magenta), and chromatin (Hoechst, blue) in oocytes. Arrow shows the same bivalent at different magnifications. Scale bars; yellow, 20 µm; white, 2 µm. b All C–KT separations are plotted at 4 h after NEBD following the indicated drug additions (****P < 0.0001, one-way ANOVA with Tukey’s post-hoc test, bivalent numbers are indicated. Measurements were made on 12, 7 and 4 oocytes with 3, 3 and 2 independent repeats, for untreated, nocodazole and monastrol groups, respectively). c C–KT separation distances for bivalents in oocytes 4 h after NEBD. The two centromeres of each bivalent within an oocyte are paired (connecting grey line). Bold lines indicate means and standard deviations. (*P < 0.05, paired t-test, two-tailed). Measurements were made on 12 oocytes, combined from three independent experiments. d Cortical (blue) and central (orange) C–KT separations for oocytes at 7 h after NEBD, with or without prior treatment with cytochalasin B (for 1 h). Bivalent numbers are indicated, with measurements made on 12 oocytes with cytochalasin and 14 without, each combined from three independent experiments. Differences between each group were tested using one-way ANOVA with Tukey’s post-hoc test; different letters denote significant difference (P < 0.05). b, d Horizontal lines for each condition represent means and the error bars are s.d