Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 43: Cytoskeletal Filaments
BP 43.5: Vortrag
Mittwoch, 22. März 2017, 16:30–16:45, HÜL 386
Mechanisms of microtubule nucleation and size in spindles — •Franziska Decker1,2, Elisa Rieckhoff1,2, Benjamin Dalton1,2, David Oriola1,2, and Jan Brugues1,2 — 1Max Planck Institute for the Physics of Complex Systems — 2Max Planck Institute of Molecular Cell Biology and Genetics
The spindle is the protein machinery responsible for segregating the genetic material into the daughter cells. Microtubules,the main building blocks of the spindle,have a lifetime of 20 sec while the entire spindle remains for minutes or even up to hours. Thus, maintenance of the spindle requires constant creation of new microtubules through microtubule nucleation. Here, we used laser ablation to measure the minus ends of monopolar spindles in Xenopus leaevis egg extract as a proxy to microtubule nucleation. We found that microtubule dependent microtubule nucleation explains the nucleation profile and microtubule density in these structures, with the amount of nucleators activated in chromosomes setting the number of microtubules in spindles. This nucleation mechanism could account for the scaling of spindles with cell volume as observed in early embryogenesis or spindles encapsulated in extract, and provides an alternative prediction to previous models based on microtubule dynamics. To test whether microtubule dynamics or microtubule nucleation are responsible for the scaling of spindles, we performed measurements of microtubule dynamics and nucleation during the early rounds of cell division in Zebrafish embryos.