Intercellular communication in the eight-cell stage of Xenopus laevis development: a study using dye coupling.

We report an investigation of dye coupling in the eight-cell stage of Xenopus laevis development. Our results indicate that fluorophors injected into micrometers at this stage pass only to sister cells (the corresponding macromeres) and that detectable dye transfer occurs only via cytoplasmic bridges, which persist for about the first two-thirds of the fourth cell cycle. We had previously shown that the dorsoventral polarity of the Xenopus embryo is regulated by a cell interaction that occurs at the end of the fourth cell cycle and we conclude that this cell interaction probably does not require cytoplasmic bridges or gap junctions.