Displacement of cleavage plane in the sea urchin egg by locally applied taxol.
Taxol enhanced assembly and stability of microtubules in the mitotic apparatus and subsequently inhibited chromosome movement and cleavage when injected in the sea urchin egg as reported previously [Y. Hamaguchi et al., 1987: Cell Struct. Funct. 12:43-52]. In this study, to examine the local effect of taxol on cleavage, taxol was injected in small doses. When taxol was injected into the cortical region of the equatorial plane, the birefringence (BR) of the mitotic apparatus near the injection site increased, chromosome movement became slow near this site, and then cleavage furrow formation was inhibited in the cortex near the site, although chromosome movement and cleavage furrow formation were apparently normal in the other side of the cell. When taxol was injected in the polar cortex, BR of the mitotic apparatus near the injection site was enhanced and then the cleavage furrow was displaced toward this site from the equator. Accordingly, resultant blastomeres were unequal in size. The enhancement of microtubule assembly and stabilization of microtubule dynamics, which were detected as the increase in BR were confirmed by immunofluorescence microscopy with anti-tubulin antibody. Consequently, it was found that taxol injection caused local suppression of dynamics of microtubules in the cell, thereby modifying cleavage furrow formation.
Hamaguchi
Y
Y
Biological Laboratory, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Japan. yhamaguc@bio.titech.ac.jp
D000818:Animals; D016764:Cell Polarity / Q000187:drug effects; D002875:Chromosomes / Q000187:drug effects*; D002970:Cleavage Stage, Ovum / Q000187:drug effects*; D008845:Microinjections; D008859:Microscopy, Polarization; D008870:Microtubules / Q000187:drug effects*; D008938:Mitosis / Q000187:drug effects*; D010063:Ovum / Q000187:drug effects* / Q000648:ultrastructure; D017239:Paclitaxel / Q000494:pharmacology*; D012617:Sea Urchins
D017239:Paclitaxel