JXB Advance Access originally published online on June 20, 2005
Journal of Experimental Botany 2005 56(418):2131-2137; doi:10.1093/jxb/eri211
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RESEARCH PAPER |
Epothilone D affects cell cycle and microtubular pattern in plant cells
1Biozentrum der Universität, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 22, D-06120 Halle (Saale), Germany
2Leibniz-Institut für Pflanzenbiochemie, Weinberg 3, PO Box 110432, D-06120 Halle (Saale), Germany
* To whom correspondence should be addressed. Fax: +49 345 5582 1509. E-mail: bhause{at}ipb-halle.de
Epothilones, macrocyclic lactones from culture filtrates of the myxobacterium Sorangium cellulosum, are known as taxol-like microtubular drugs in human medicine. To date, nothing is known about the effect of epothilones on microtubules (MTs) in plant cells and/or on the plant cell cycle. As shown in this report, the treatment of tomato cell suspension cultures with epothilone D produced a continuous increase in the mitotic index. Doseresponse curves revealed that epothilone D alters the mitotic index at concentrations as low as 1.5 µM. Mitotic arrest was already visible after only 2 h of treatment, and 55% of the cells were arrested after 24 h. As shown by immunocytological methods, abnormal spindles are formed during metaphase, which leads to a random distribution of chromosomes in the whole cell and prevents the formation of a metaphase plate. The process of chromosome decondensation does not seem to be affected, because micronuclei form at the same place with the distributed chromosomes. This suggests that epothilone D influences the stability of plant MTs mainly during metaphase of the mitotic cycle. In metaphase, the effects of epothilone D seem to be irreversible, because cells with an abnormal spindle could not be recovered after removal of the drug.
Key words: Cell cycle, epothilone, immunofluorescence, Lycopersicon esculentum, microtubuli, mitosis, mitotic arrest