Nuclear and division-plane positioning revealed by optical micromanipulation

Year: 2005

Authors: Tolic-Nørrelykke I.M., Sacconi L., Stringari C., Raabe I., Pavone FS.

Autors Affiliation: European Laboratory for Nonlinear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino (Florence), Italy
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
Department of Physics, University of Trento, Via Sommarive 14, 38050 Povo (Trento), Italy
Department of Physics, University of Bologna, Viale C. Berti Pichat 6/2, 40127 Bologna, Italy
Department of Physics, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino (Florence), Italy

Abstract: The position of the division plane affects cell shape and size, as well as tissue organization. Cells of the fission yeast Schizosaccharomyces pombe have a centrally placed nucleus and divide by fission at the cell center. Microtubules (MTs) are required for the central position of the nucleus [1-4]. Genetic studies lead to the hypothesis that the position of the nucleus may determine the position of the division plane [5-10]. Alternatively, the division plane may be positioned by the spindle or by morphogen gradients or reaction diffusion mechanisms [7, 11]. Here, we investigate the role of MTs in nuclear positioning and the role of the nucleus in division-plane positioning by displacing the nucleus with optical tweezers. A displaced nucleus returned to the cell center by MT pushing against the cell tips. Nuclear displacement during interphase or early prophase resulted in asymmetric cell division, whereas displacement during prometaphase resulted in symmetric division as in unmanipulated cells. These results suggest that the division plane is specified by the predividing nucleus. Because the yeast nucleus is centered by MTs during interphase but not in mitosis, we hypothesize that the establishment of the division plane at the beginning of mitosis is an optimal mechanism for accurate symmetric division in these cells.


Volume: 15 (13)      Pages from: 1212  to: 1216

KeyWords: Optical Tweezers
DOI: 10.1016/j.cub.2005.05.052

Citations: 75
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