Figure 4: Chromosome merge is dependent on microtubules.

(a) Control embryo (left panels) or embryo treated with 1 μM Nocodazole around NEBD (right panels) expressing EB3–GFP (upper panel, green, Z-projection over 20 μm) and His–RFP (purple or black, Z-projection over 20 μm). One image is shown every 30 min. Scale bar, 10 μm. (b) Left panel: Embryo treated with 1 μM Nocodazole around NEBD expressing His–RFP (purple, Z-projection over 20 μm) during the migration of the two sets of chromosomes. Scale bar, 10 μm. Right panel: graph showing the position of the centroid of the two sets of chromosomes in the referential of the embryo (0 being the centre) from NEBD for embryos treated with 1 μM Nocodazole around NEBD. The scale is represented by the white box on the left panel. Each colour represents an embryo. The arrows point to the last position recorded. Points are 30 min apart. (c) Graph showing the maximum distance (that is, the distance between the points furthest apart on the trajectories) of chromosome motion in controls (black bars, from Supplementary Fig. 1c) and embryos treated with 1 μM Nocodazole around NEBD (green bars) during the migration of the two sets of chromosomes towards the embryo centre (female: left bars; male: right bars). Mean of 11 controls and 6 Nocodazole-treated embryos are shown over 2 independent experiments. s.e.m. is plotted on each bar. Statistical significance of differences is assessed with Mann–Whitney tests (P values: female 0.0011; male 0.0011). (d) Dot plot showing if the two sets of chromosome merge as a function of initial chromosome distance at NEBD for 10 embryos expressing Myosin-Vb. Mean distance and s.e.m. are plotted for each condition.