JCS02873 Supplementary Material

Files in this Data Supplement:

• Movie 1 -

  Movie 1 (corresponds to Fig. 2A). Time-lapse imaging of asymmetric cleavage in ascidian embryo. The pair of B5.2 blastomeres is viewed by DIC optics. In the first part of the movie the centrosome can be observed as a clear zone in front of the interphase nucleus. Led by the centrosome, the nucleus stretches and migrates near the posterior cortex. In the second part of the movie (from 11 seconds), the nuclei are already positioned near the cortex. After nuclear breakdown the two CABs are visible as a smooth moustache-shaped zone. One spindle pole in each cell approaches the CAB and unequal cleavage ensues. The dynamic behaviour of the CAB as it changes size and shape during the cell cycle is also apparent in this sequence. Frames were collected every 10 seconds and are displayed at a rate of 30 per second.

• Movie 2 -

  Movie 2 (corresponds to Fig. 4I). aPKC-rich particles in the CAB. Sequential confocal z sections 1.2 mm apart of the surface of B4.1 blastomeres (posterior view) labelled for aPKC. aPKC-rich particles line the blastomere surface and are densely packed at the position of the CABs. Magnification 403, zoom 8. The field measures 45 mm on each side.

• Movie 3 -

  Movie 3 (corresponds to Figs 7B and C). Multilayered structure of the CAB.  B5.2 blastomeres labelled for aPKC (green) and mitochondria (red). Sequential confocal z sections show the unlabelled space occupied by the cER/mRNA domain between the cortical patch of aPKC and the mitochondria-rich myoplasm.

• Movie 4 -

  Movie 4 (corresponds to Fig. 7I). Microtubules contact the CAB. Plus ends of microtubules (red) contact the cell surface at the aPKC-rich domain (green) and also reach the cortex adjacent to the CAB. This B4.1 blastomere in prophase is part of an 8-cell stage embryo viewed from the side, similar to those in Fig. 1B and Fig. 4E. The film traverses the blastomere via confocal z sections at intervals of 0.4 mm. Magnification 633, zoom 2.6.