Fig. 4. Spindle alignment takes place early in the cell cycle; large angle oscillations do not occur. (A) Different spindle orientation behaviour is shown in frames from 4D series of tau-GFP injected embryos; LA, spindle is already set up within 25° of the long axis at prophase/prometaphase; RLA, spindle rotates into the long axis; SA, spindle is already set up within 25° of the short axis; RSA, spindle rotates into the short axis (see Movie 6 in the supplementary material). (B) Quantification of spindle orientation behaviour in 216 cells from 11 different embryos. The majority of spindles are already close to the long axis when the spindle is set up. (C) Example frames of a spindle rotating into the long axis, RLA. Scale bars in A,C: 20 µm. (D) Analysis of the temporal dynamics of such rotation movements in 12 cells from three different embryos. The angular changes (y-axis) with respect to the long axis are plotted against time (x-axis). Time intervals between frames are 92 seconds in cells 1-8 and 75 seconds in cells 9-12. The broken line indicates 25°. Overall, orientation movements into the long axis occur via small angle adjustments as for example in graphs 1 and 11 (number 11 corresponds to the cell shown in C).