title: Taxol-induced microtubule asters in mitotic extracts of Xenopus eggs: requirement for phosphorylated factors and cytoplasmic dynein.
abstract: Taxol, a microtubule stabilizing drug, induces the formation of numerous microtubule asters in the cytoplasm of mitotic cells (De Brabander, M., G. Geuens, R. Nuydens, R. Willebrords, J. DeMey. 1981. Proc. Natl. Acad. Sci. USA. 78:5608-5612). The center of these asters share with spindle poles some characteristics such as the presence of centrosomal material and calmodulin. We have recently reproduced the assembly of taxol asters in a cell-free system (Buendia, B., C. Antony, F. Verde, M. Bornens, and E. Karsenti. 1990. J. Cell Sci. 97:259-271) using extracts of Xenopus eggs. In this paper, we show that taxol aster assembly requires phosphorylation, and that they do not grow from preformed centers, but rather by a reorganization of microtubules first crosslinked into bundles. This process seems to involve sliding of microtubules along each other and we show that cytoplasmic dynein is required for taxol aster assembly. This result provides a possible functional basis to the recent findings, that dynein is present in the spindle and enriched near spindle poles (Pfarr, C. M., M. Cove, P. M. Grissom, T. S. Hays, M. E. Porter, and J. R. McIntosh. 1990. Nature (Lond.). 345:263-265; Steuer, E. R., L. Wordeman, T. A. Schroer, and M. P. Sheetz. 1990. Nature (Lond.). 345:266-268).
authors.affiliation: European Molecular Biology Laboratory, Cell Biology Programme, Heidelberg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Verde
authors.forename: J M
authors.initials: JM
authors.lastname: Berrez
authors.forename: C
authors.initials: C
authors.lastname: Antony
authors.forename: E
authors.initials: E
authors.lastname: Karsenti
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D002474:Cell-Free System; D003593:Cytoplasm / Q000201:enzymology; D004398:Dyneins / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D007399:Interphase / Q000187:drug effects; D007700:Kinetics; D008677:Metaphase; D008854:Microscopy, Electron; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D008938:Mitosis / Q000187:drug effects; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D017239:Paclitaxel; D010766:Phosphorylation; D014638:Vanadates / Q000494:pharmacology; D014982:Xenopus laevis
chemical_list: D000470:Alkaloids; C022571:adenosine 5'-O-(3-thiotriphosphate); D014638:Vanadates; D000255:Adenosine Triphosphate; D004398:Dyneins; D017239:Paclitaxel