Effects of some cytoskeleton inhibitors on ooplasmic segregation in the Nereis virens egg.

The ooplasmic segregation in the Nereis virens egg starts after completion of cortical reaction. During ooplasmic segregation the radial symmetrical pattern of the oocyte transforms into polarized stratified structure with different kinds of cytoplasm regularly distributed along the animal-vegetal axis. The beginning of oocyte polarization is associated with the generation of the mitotic spindle and is sensitive to microtubule inhibitors. By analyzing the effect of colchicine, taxol, nocodazole and cytochalasin B, we show that the mechanisms of ooplasmic segregation have an integrated complex nature and include interactions of microtubules and microfilaments. The inhibition of any of these elements delays or disturbs the ooplasmic segregation and simultaneous disruption of microtubules and microfilaments functions leads to total cessation of the process.