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BP: Fachverband Biologische Physik

BP 25: Oscillatory Systems

BP 25.4: Talk

Thursday, March 29, 2007, 15:30–15:45, H44

Nuclear oscillations during sexual reproduction in yeast — Sven Vogel and •Iva Tolic-Norrelykke — Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany

When two cells of the fission yeast Schizosaccharomyces pombe mate, the cell nucleus oscillates from one end of the cell to the other with a period of about 5 minutes and a total duration of a few hours. The biological significance of the nuclear oscillation seems to be in facilitating the spatial alignment of homologous chromosomes.

We set out to determine which forces drive the nuclear oscillation and how the force generation is spatially and temporally regulated. The nuclear oscillation is dependent on astral microtubules (MTs) radiating from the spindle pole body and on cytoplasmic dynein, a minus end directed MT motor. By cutting single MTs using laser nanosurgery, we can distinguish between different models of force generation and identify a subset of MTs that are responsible for nuclear oscillation. Our data provide direct evidence that the main forces contributing to the nuclear oscillation are pulling forces, which are typically generated at the cell ends, and that the event of force generation is driven by the interaction of forward-extending MTs with the cell end cortex.