Regensburg 2013 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 5: Cytoskeleton
BP 5.7: Vortrag
Montag, 11. März 2013, 16:45–17:00, H43
Chromosome oscillations in mammalian cells — •Federica Tavano1, Nenad Pavin2, and Iva M. Tolic-Norrelykke1 — 1Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany — 2Department of Physics, Faculty of Science, University of Zagreb, 10002 Zagreb, Croatia
Mitosis is the process by which eukaryotic cells replicate chromosomes into two identical sets that segregate to the nuclei of the two daughter cells. During mitosis, sister chromatids connect to mitotic spindle microtubules via protein complexes called kinetochores, and oscillate around the equatorial plane of the spindle. These oscillations are correlated with the microtubule plus-end dynamics. However, the mechanism of the oscillations is not known. Here we show that kinetochores in mammalian epithelial cells move roughly with a constant velocity until they switch the direction of movement. During the movement, the distance between sister kinetochores increases. During directional switches, sister kinetochores are not synchronized: The leading kinetochore stops while the trailing one continues moving, decreasing the distance between the sister kinetochores. These results suggest that the sister kinetochores are under tension during their movement, whereas they get compressed when they switch direction. Moreover, these data imply that the microtubules on the leading side undergo rescue before the microtubules on the trailing side undergo catastrophe. We propose that forces on the kinetochores synchronize microtubule dynamics, which is required for chromosome oscillations.