Regensburg 2019 – scientific programme
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BP: Fachverband Biologische Physik
BP 30: Cell mechanics III
BP 30.2: Talk
Thursday, April 4, 2019, 16:30–16:45, H4
Moving chromosomes in intact cell nuclei — Matthäus Mittasch1, Anatol Fritsch1, Michael Nestler2, Juan Iglesias1, Archit Bhatnagar1, Kaushikaram Subramanian1, Axel Voigt2, and •Moritz Kreysing1 — 1MPI of Cell Biology, Dresden — 2Department of Mathematics, TU Dresden
Recently we have described that we can move the cytoplasm of cells and developing embryos in a non-invasive manner (1). Here we demonstrate that we can optically generate hydrodynamic flows also in the nucleoplasm of developing C. elegance embryos during mitosis. Induced flows cause the instantaneous motion of chromosomes, indicating the absence of inertia and elastic creep relaxation in the nucleoplasm. Furthermore, chromosomes may be moved in time-reversal manner, which characterizes the mitotic nucleus as Stokes fluid type suspension of colloidal particles. We explicitly show that prophase chromosomes are free to exchange neighbors. Using the Stokes Einstein relation we estimate flow induced forces to be on the order of 10-100fN only, emphasizing the non-invasive character of induced flows. Biologically interesting, we find that altering chromsome position does not impact developmental success. This largely rules out a functional relevance of trans-mitotic inheritance of chromosome positioning.
Reference: Mittasch et al., " Non-invasive perturbations of intracellular flow reveal physical principles of cell organization", Nature Cell Biology 1 (2018)