title: Characterization and expression of a maternal axolotl cyclin B1 during oogenesis and early development.
abstract: The M phase promoting factor (MPF) is a dimer composed of a catalytic Cdk1 subunit and a Cyclin B regulatory subunit. We have characterized a cDNA containing the entire coding sequence of an axolotl Cyclin B1 protein that is able to promote MPF activity when added to a fraction from prophase I oocytes that contains monomeric Cdk1. The axolotl cyclin B1 gene is expressed as a maternal mRNA in oocytes and early embryos. Its poly(A) tail length increases in metaphase II oocytes and then decreases regularly during the first embryonic cell cycles. Endogenous Cyclin B1 protein is first expressed during oocyte meiotic maturation. Its level oscillates after fertilization and is coordinated to the phosphorylation level of tyrosine 15 residue of Cdk1 (pTyr15), with both maxima preceding each cell division. As expected, when translated into microinjected oocytes, axolotl Cyclin B1 induces the resumption of meiosis. In electrically activated unfertilized eggs (UFE), Cyclin B1 and pTyr15 cyclic accumulations are observed with kinetics different from those of the early embryonic cycles. The axolotl embryo and UFE provide interesting in vivo comparative models for studying events controlling Cyclin B1 regulation during development.
authors.affiliation: Equipe Biochimie du Développement précoce, Laboratoire de Biologie du Développement, UMR CNRS 7622, Université Pierre et Marie Curie, 75252 Paris cedex 05, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Pelczar
authors.forename: Stéphane
authors.initials: S
authors.lastname: Caulet
authors.forename: Catherine
authors.initials: C
authors.lastname: Thibier
authors.forename: Geneviève
authors.initials: G
authors.lastname: Aubet
authors.forename: Robert
authors.initials: R
authors.lastname: Poulhe
authors.forename: Ioanna
authors.initials: I
authors.lastname: Vallianou
authors.forename: Masakane
authors.initials: M
authors.lastname: Yamashita
authors.forename: Yannick
authors.initials: Y
authors.lastname: Andéol
mesh_terms: D000558:Ambystoma mexicanum / Q000196:embryology* / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019926:Cyclin B / Q000235:genetics*; D056744:Cyclin B1; D018076:DNA, Complementary / Q000235:genetics; D047108:Embryonic Development / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D016200:Maturation-Promoting Factor / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009866:Oogenesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D019926:Cyclin B; D056744:Cyclin B1; D018076:DNA, Complementary; D012333:RNA, Messenger; D016200:Maturation-Promoting Factor