Requirement for Microtubules in New Membrane Formation during Cytokinesis ofXenopusEmbryos

Abstract

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.

Versatile fluorescent probes for actin filaments based on the actin‐binding domain of utrophin

“…We therefore also compared the ability of GFP-UtrCH to label F-actin in samples extracted with methanol after an initial aldehyde fixation. Consistent with previous studies [Danilchik et al, 1998] methanol extraction did indeed improve microtubule visualization relative to aldehyde-only fixed samples (Fig. 1b).…”

Identification of recessive maternal‐effect mutations in the zebrafish using a gynogenesis‐based method

“…However, we cannot rule out the possibility that this late effect is a secondary consequence of early cellularization defects. We have shown previously that nebel is required for the maturation of a microtubule array at the forming furrow, the furrow microtubule array (FMA; Danilchik et al, 1998;Jesuthasan, 1998), which in turn is required for the exocytosis of intraembryonic membrane vesicles at the furrow during cytokinesis (Pelegri et al, 1999). We have shown that this array is also required for the aggregation of the germ plasm during furrow maturation (Pelegri et al, 1999).…”

Membrane dynamics of cleavage furrow closure in Xenopus laevis

“…Rather, the surface area taken up in protrusions probably serves as a sink for excess membrane added along the basolateral surface, helping to regulate its overall expansion during basolateral-surface contact: when the protrusive band is obliterated after cytochalasin B treatment, a massive expansion of exposed new membrane results ( Fig. 7B; see also Bluemink and de Laat, 1973;Drechsel et al, 1996;Danilchik et al, 1998).…”