Fig. 4. Translocation of kinesin light chain (KLC)-GFP particles during cortical rotation. Xenopus KLC-GFP was expressed and imaged with a scanning confocal microscope in the vegetal shear zone of immobilized live eggs during the first cell cycle. (A) KLC-GFP particles (green) are observed in the vegetal shear zone during peak rotation. Yolk platelets of the core cytoplasm are stained in red. The starting positions of four KLC-GFP particles are circled, and three neighboring yolk platelets are marked with asterisks. (B) Time-lapse image showing the same field of view 38 seconds later than in A. Owing to the immobilization of the egg, the core rotates opposite to the normal direction of cortical rotation, as seen by the displacement of the three core yolk platelets (Y) from right to left. The KLC-GFP particles have translocated a longer distance in the opposite direction (i.e. in the same direction cortical rotation would normally move), from left to right. Scale bar: 5 µm. Reproduced, with permission, from Weaver et al. (Weaver et al., 2003).