title: Control of Cdc6 accumulation by Cdk1 and MAPK is essential for completion of oocyte meiotic divisions in Xenopus.
abstract: Vertebrate oocytes proceed through the first and the second meiotic division without an intervening S-phase to become haploid. Although DNA replication does not take place, unfertilized oocytes acquire the competence to replicate DNA one hour after the first meiotic division by accumulating an essential factor of the replicative machinery, Cdc6. Here, we show that the turnover of Cdc6 is precisely regulated in oocytes to avoid inhibition of Cdk1. At meiosis resumption, Cdc6 is expressed but cannot accumulate owing to a degradation mechanism that is activated through Cdk1. During transition from the first to the second meiotic division, Cdc6 is under the antagonistic regulation of B-type cyclins (which interact with and stabilize Cdc6) and the Mos-MAPK pathway (which negatively controls Cdc6 accumulation). Because overexpressing Cdc6 inhibits Cdk1 reactivation and drives oocytes into a replicative interphasic state, the fine-tuning of Cdc6 accumulation is essential to ensure two meiotic waves of Cdk1 activation and to avoid unscheduled DNA replication during meiotic maturation.
authors.affiliation: UPMC Univ Paris 06, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France CNRS, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France.
authors.forename: Enrico M
authors.initials: EM
authors.lastname: Daldello
authors.affiliation: UPMC Univ Paris 06, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France CNRS, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France.
authors.forename: Tran
authors.initials: T
authors.lastname: Le
authors.affiliation: UPMC Univ Paris 06, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France CNRS, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Poulhe
authors.affiliation: UPMC Univ Paris 06, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France CNRS, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Jessus
authors.affiliation: UPMC Univ Paris 06, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France CNRS, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Haccard
authors.affiliation: UPMC Univ Paris 06, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France CNRS, UMR7622, Biologie du Développement, Institut de Biologie Paris-Seine (IBPS), 75005 Paris, France aude-isabelle.dupre@upmc.fr.
authors.forename: Aude
authors.initials: A
authors.lastname: Dupré
mesh_terms: D000818:Animals; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008540:Meiosis / Q000502:physiology*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: C118388:Cdc6 protein, Xenopus; D002868:Chromosomal Proteins, Non-Histone; D029867:Xenopus Proteins; D016203:CDC2 Protein Kinase; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: Cdc6; Cdk1; Meiotic division; Xenopus oocyte