Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 43: Cytoskeletal Filaments

BP 43.7: Talk

Wednesday, March 22, 2017, 17:00–17:15, HÜL 386

Microtubule pivoting and minus end directed motors drive the formation of the mitotic spindle — •Ivana Ban¹, Marcel Prelogović¹, Lora Winters², Ana Milas³, Iva Tolić^2,3, and Nenad Pavin¹ — ¹Faculty of science , University of Zagreb, Croatia — ²Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany — ³Division of Molecular Biology, Ruder Bošković Institute, Zagreb, Croatia

During mitosis, the genetic material is divided into two equal parts by the spindle. This complex micro-machine is made of chromosomes, microtubules (MTs) and a variety of accessory proteins. In the fission yeast Schizosaccharomyces pombe, the mitotic spindle is a bundle of MTs emanating from two spindle pole bodies, whose formation is mediated by motor proteins. A key question is what are the physical principles underlying the formation of a mitotic spindle. In this work, we combine theory and experiment to describe how angular motion of MTs and forces exerted by motor proteins lead to spindle formation. In our model, MTs explore their environment by performing angular movement around the spindle poles, until two MTs come into close proximity, allowing motor proteins accumulate in the overlap region. In the case of minus end directed motors, this leads to formation of antiparallel bundles. We experimentally observed random angular motion of MTs as well as accumulation of Cut7 motor proteins in the overlap region, followed by antiparallel bundle formation. In conclusion, these results provide an explanation for how the angular Brownian motion and motor proteins drive the formation of a stable mitotic spindle.