Requirement for microtubules in new membrane formation during cytokinesis of Xenopus embryos.

In cleaving Xenopus eggs, exposure to nocodazole or cold shock prevents the addition of new plasma membrane to the cleavage plane and causes furrows to recede, suggesting a specific role for microtubules in cytokinesis. Whole-mount confocal immunocytochemistry reveals a ring of radially arranged, acetylated microtubule bundles at the base of all advancing cleavage furrows, from the first cleavage through the midblastula stage. We hypothesize that this novel microtubular structure is involved in transporting maternal stores of membrane in the subcortex to a site of membrane addition near the leading edge of the furrow.