Figure 3.

Furrow-stimulating complexes in polyspermic Xenopus laevis eggs. Eggs fixed at successive times between first anaphase and first cleavage, with confocal sections oriented as in Figure 2. Cleavage has just initiated at the animal pole in C. The eggs in A and B were fertilized with two sperm and in C with four, but asters are only visible for three. Note recruitment of CPC and centralspindlin to a subset of boundaries between asters in B and C. In B, the aster morphology shows that the CPC-positive boundaries are between asters from the same spindle. In C, we infer the same is true given classic evidence that furrows cut through spindles in frog eggs and not between them (Fig. 1C). (Modified, with permission, from Field et al. 2015.)