REQUIREMENT FOR MICROTUBULES IN NEW MEMBRANE FORMATION DURING CYTOKINESIS OF XENOPUS EMBRYOS

In cleaving Xenopus eggs, exposure to nocodazole or cold shock prevent s the addition of new plasma membrane to the cleavage plane and causes furrows to recede, suggesting a specific role for microtubules in cyt okinesis. Whole-mount confocal immunocytochemistry reveals a ring of r adially arranged, acetylated microtubule bundles at the base of all ad vancing cleavage furrows, from the first cleavage through the midblast ula stage. We hypothesize that this novel microtubular structure is in volved in transporting maternal stores of membrane in the subcortex to a site of membrane addition near the leading edge of the furrow. (C) 1998 Academic Press.