title: Rebuilding MTOCs upon centriole loss during mouse oogenesis.
abstract: The vast majority of animal cells contain canonical centrosomes as a main microtubule-organizing center defined by a central pair of centrioles. As a rare and striking exception to this rule, vertebrate oocytes loose their centrioles at an early step of oogenesis. At the end of oogenesis, centrosomes are eventually replaced by numerous acentriolar microtubule-organizing centers (MTOCs) that shape the spindle poles during meiotic divisions. The mechanisms involved in centrosome and acentriolar MTOCs metabolism in oocytes have not been elucidated yet. In addition, little is known about microtubule organization and its impact on intracellular architecture during the oocyte growth phase following centrosome disassembly. We have investigated this question in the mouse by coupling immunofluorescence and live-imaging approaches. We show that growing oocytes contain dispersed pericentriolar material, responsible for microtubule assembly and distribution all over the cell. The gradual enlargement of PCM foci eventually leads in competent oocytes to the formation of big perinuclear MTOCs and to the assembly of large microtubule asters emanating from the close vicinity of the nucleus. Upon meiosis resumption, perinuclear MTOCs spread around the nuclear envelope, which in parallel is remodelled before breaking-down, via a MT- and dynein-dependent mechanism. Only fully competent oocytes are able to perform this dramatic reorganization at NEBD. Therefore, the MTOC-MT reorganization that we describe is one of key feature of mouse oocyte competency.
authors: Collège de France, Center for Interdisciplinary Research in Biology, CIRB, UMR CNRS 7241/INSERM-U1050, Equipe Labellisée Ligue Contre le Cancer, 11 place Marcelin Berthelot, 75005 Paris, France; Memolife Laboratory of Excellence and Paris Science Lettre, France.
authors: Małgorzata
authors: M
authors: Luksza
authors: Isabelle
authors: I
authors: Queguigner
authors: Marie-Hélène
authors: MH
authors: Verlhac
authors: Stéphane
authors: S
authors: Brunet
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002502:Centrioles / Q000378:metabolism*; D004398:Dyneins / Q000378:metabolism; D005260:Female; D008540:Meiosis; D051379:Mice; D022101:Microtubule-Organizing Center / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D009866:Oogenesis
chemical_list: D004398:Dyneins
keywords: Acentriolar MTOC; Growth phase; Mouse; NEBD; Oogenesis