title: Micromechanics of the vertebrate meiotic spindle examined by stretching along the pole-to-pole axis.
abstract: The meiotic spindle is a bipolar molecular machine that is designed to segregate duplicated chromosomes toward the opposite poles of the cell. The size and shape of the spindle are considered to be maintained by a balance of forces produced by molecular motors and microtubule assembly dynamics. Several studies have probed how mechanical perturbations of the force balance affect the spindle structure. However, the spindle's response to a stretching force acting at the spindle pole and along its long axis, i.e., the direction in which chromosomes are segregated, has not been examined. Here, we describe a method to apply a stretching force to the metaphase spindle assembled in Xenopus egg extracts and measure the relationship between the force and the three-dimensional deformation of the spindle. We found that the spindle behaves as a Zener-type viscoelastic body when forces are applied at the spindle pole, generating a restoring force for several minutes. In addition, both the volume of the spindle and the tubulin density are conserved under the stretching force. These results provide insight into how the spindle size is maintained at metaphase.
authors: Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
authors: Jun
authors: J
authors: Takagi
authors: Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
authors: Takeshi
authors: T
authors: Itabashi
authors: Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
authors: Kazuya
authors: K
authors: Suzuki
authors: Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, New York; JST PRESTO, New York, New York.
authors: Yuta
authors: Y
authors: Shimamoto
authors: Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, New York.
authors: Tarun M
authors: TM
authors: Kapoor
authors: Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo, Japan; Waseda Bioscience Research Institute in Singapore (WABIOS), Singapore. Electronic address: ishiwata@waseda.jp.
authors: Shin'ichi
authors: S
authors: Ishiwata
mesh_terms: D000818:Animals; D004548:Elasticity; D009865:Oocytes / Q000378:metabolism; D008941:Spindle Apparatus / Q000737:chemistry / Q000378:metabolism*; D013314:Stress, Mechanical; D014981:Xenopus