title: From meiosis to mitosis - the sperm centrosome defines the kinetics of spindle assembly after fertilization in Xenopus.
abstract: Bipolar spindle assembly in the vertebrate oocyte relies on a self-organization chromosome-dependent pathway. Upon fertilization, the male gamete provides a centrosome, and the first and subsequent embryonic divisions occur in the presence of duplicated centrosomes that act as dominant microtubule organizing centres (MTOCs). The transition from meiosis to embryonic mitosis involves a necessary adaptation to integrate the dominant chromosome-dependent pathway with the centrosomes to form the bipolar spindle. Here, we took advantage of the Xenopus laevis egg extract system to mimic in vitro the assembly of the first embryonic spindle and investigate the respective contributions of the centrosome and the chromosome-dependent pathway to the kinetics of the spindle bipolarization. We found that centrosomes control the transition from the meiotic to the mitotic spindle assembly mechanism. By defining the kinetics of spindle bipolarization, the centrosomes ensure their own positioning to each spindle pole and thereby their essential correct inheritance to the two first daughter cells of the embryo for the development of a healthy organism.
authors.affiliation: Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Doctor Aiguader, 88 Barcelona 08003, Spain Universitat Pompeu Fabra (UPF), Doctor Aiguader 88, Barcelona 08003, Spain.
authors.forename: Tommaso
authors.identifier: 0000-0003-2544-5340
authors.initials: T
authors.lastname: Cavazza
authors.affiliation: Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Doctor Aiguader, 88 Barcelona 08003, Spain Universitat Pompeu Fabra (UPF), Doctor Aiguader 88, Barcelona 08003, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Peset
authors.affiliation: Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Doctor Aiguader, 88 Barcelona 08003, Spain Universitat Pompeu Fabra (UPF), Doctor Aiguader 88, Barcelona 08003, Spain Institució Catalana de Recerca I Estudis Avançats (ICREA), Passeig de Lluis Companys 23, Barcelona 08010, Spain isabelle.vernos@crg.eu.
authors.forename: Isabelle
authors.identifier: 0000-0003-1469-9214
authors.initials: I
authors.lastname: Vernos
mesh_terms: D000818:Animals; D018385:Centrosome / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D005260:Female; D005306:Fertilization / Q000235:genetics; D059566:M Phase Cell Cycle Checkpoints / Q000235:genetics*; D008297:Male; D008540:Meiosis / Q000235:genetics*; D022101:Microtubule-Organizing Center / Q000378:metabolism; D008938:Mitosis / Q000235:genetics*; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism; D013094:Spermatozoa / Q000254:growth & development; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics
keywords: Centrosome; Embryonic mitosis; Meiosis; Spindle assembly; Xenopus