ABSTRACT
An attempt was undertaken to develop a model system based on artificial cell cycle synchronization by means of reversible mitosis blocking in zebrafish embryos for studying the role of cell cycle synchrony in embryogenesis. Dechorionized and intact embryos at the stages of 512-cell blastula and 75% epiboly were treated with nocodazole and then washed within several times of exposure. When working on dechorionized embryos, we succeeded to obtain complete block mitosis in the presence of low nocodazole concentrations: 0.5-1.0 microg/ml. Block of mitosis was relieved in all experimental series within a certain time after the beginning of washing. This inertia depended on both nocodazole concentration and duration of treatment. The nocodazole elimination was significantly accelerated only after five (or more) changes of washing medium containing DMSO. As a result, the conditions were established for obtaining a parasynchronous cell population in the zebrafish gastrulas with a peak of mitosis up to 17.2%.
