title: A narrow window of cortical tension guides asymmetric spindle positioning in the mouse oocyte.
abstract: Cell mechanics control the outcome of cell division. In mitosis, external forces applied on a stiff cortex direct spindle orientation and morphogenesis. During oocyte meiosis on the contrary, spindle positioning depends on cortex softening. How changes in cortical organization induce cortex softening has not yet been addressed. Furthermore, the range of tension that allows spindle migration remains unknown. Here, using artificial manipulation of mouse oocyte cortex as well as theoretical modelling, we show that cortical tension has to be tightly regulated to allow off-center spindle positioning: a too low or too high cortical tension both lead to unsuccessful spindle migration. We demonstrate that the decrease in cortical tension required for spindle positioning is fine-tuned by a branched F-actin network that triggers the delocalization of myosin-II from the cortex, which sheds new light on the interplay between actin network architecture and cortex tension.
authors.affiliation: CIRB, Collège de France, and CNRS-UMR7241 and INSERM-U1050, Equipe labellisée Ligue contre le Cancer, Paris F-75005, France.
authors.forename: A
authors.initials: A
authors.lastname: Chaigne
authors.affiliation: Université Evry Val d'Essonne, LAMBE, Boulevard F Mitterrand, Evry 91025, France.
authors.forename: C
authors.initials: C
authors.lastname: Campillo
authors.affiliation: 1] Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel [2].
authors.forename: N S
authors.initials: NS
authors.lastname: Gov
authors.affiliation: 1] UMR7600-CNRS/UPMC, 4 Place Jussieu, Paris F-75005, France [2].
authors.forename: R
authors.initials: R
authors.lastname: Voituriez
authors.affiliation: 1] CNRS-UMR168, Paris F-75248, France [2] UPMC, 4 Place Jussieu, Paris F-75248, France [3] Institut Curie, Centre de Recherche, Laboratoire Physico-Chimie, Paris F-75248, France.
authors.forename: C
authors.initials: C
authors.lastname: Sykes
authors.affiliation: CIRB, Collège de France, and CNRS-UMR7241 and INSERM-U1050, Equipe labellisée Ligue contre le Cancer, Paris F-75005, France.
authors.forename: M H
authors.initials: MH
authors.lastname: Verlhac
authors.affiliation: CIRB, Collège de France, and CNRS-UMR7241 and INSERM-U1050, Equipe labellisée Ligue contre le Cancer, Paris F-75005, France.
authors.forename: M E
authors.initials: ME
authors.lastname: Terret
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D005260:Female; D008540:Meiosis / Q000502:physiology; D051379:Mice; D008938:Mitosis / Q000502:physiology; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism*; D011247:Pregnancy; D008941:Spindle Apparatus / Q000378:metabolism