| (a) Microtubule structure was analyzed near the beginning of the first division of a Xenopus zygote. A dense array of microtubules – the furrow microtubule array (FMA) – can be seen at the leading edge of the cleavage furrow (on the right of the photograph). The overlapping microtubules of the spindle midzone lie beneath the FMA. (b) This schematic shows how the FMA is thought to direct the transport of membrane vesicles for fusion to the cell membrane at the cleavage furrow. For simplicity, the contractile ring that lies at the cleavage furrow is not shown. Photograph kindly provided by Michael Danilchik and Kay Larkin. From Danilchik, M.V. et al.: Dev. Biol.1998, 194:47–60. |
