HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) [Supplemental Data] All Versions of this Article: 78/2/218    most recent biolreprod.107.061036v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Uzbekova, S. Articles by Uzbekov, R. Search for Related Content PubMed PubMed Citation Articles by Uzbekova, S. Articles by Uzbekov, R. Agricola Articles by Uzbekova, S. Articles by Uzbekov, R.

Spatio-Temporal Expression Patterns of Aurora Kinases A, B, and C and Cytoplasmic Polyadenylation-Element-Binding Protein in Bovine Oocytes During Meiotic Maturation¹

INRA,³ UMR85 Physiologie de la Reproduction et des Comportements, CNRS, UMR6175, Université de Tours, Haras Nationaux, 37380 Nouzilly, France CNRS UMR6061 Université de Rennes 1,⁴ Institut de Génétique et Développement de Rennes, 35043 Rennes, France Cell Cycle Group,⁵ Electron Microscopy Department, A.N. Belozersky Institute, Moscow State University, 119992 Moscow, Russia

ABSTRACT

Maturation of immature bovine oocytes requires cytoplasmic polyadenylation and synthesis of a number of proteins involved in meiotic progression and metaphase-II arrest. Aurora serine-threonine kinases—localized in centrosomes, chromosomes, and midbody—regulate chromosome segregation and cytokinesis in somatic cells. In frog and mouse oocytes, Aurora A regulates polyadenylation-dependent translation of several mRNAs such as MOS and CCNB1, presumably by phosphorylating CPEB, and Aurora B phosphorylates histone H3 during meiosis. We analyzed the expression of three Aurora kinase genes—AURKA, AURKB, and AURKC—in bovine oocytes during meiosis by reverse transcription followed by quantitative real-time PCR and immunodetection. Aurora A was the most abundant form in oocytes, both at mRNA and protein levels. AURKA protein progressively accumulated in the oocyte cytoplasm during antral follicle growth and in vitro maturation. AURKB associated with metaphase chromosomes. AURKB, AURKC, and Thr-phosphorylated AURKA were detected at a contractile ring/midbody during the first polar body extrusion. CPEB, localized in oocyte cytoplasm, was hyperphosphorylated during prophase/metaphase-I transition. Most CPEB degraded in metaphase-II oocytes and remnants remained localized in a contractile ring. Roscovitine, U0126, and metformin inhibited meiotic divisions; they all induced a decrease of CCNB1 and phospho-MAPK3/1 levels and prevented CPEB degradation. However, only metformin depleted AURKA. The Aurora kinase inhibitor VX680 at 100 nmol/L did not inhibit meiosis but led to multinuclear oocytes due to the failure of the polar body extrusion. Thus, in bovine oocyte meiosis, massive destruction of CPEB accompanies metaphase-I/II transition, and Aurora kinases participate in regulating segregation of the chromosomes, maintenance of metaphase-II, and formation of the first polar body.

aurora kinases, bovine, CPEB, gamete biology, kinases, meiosis, oocyte, oocyte development

¹Supported by grants of ANR and APIS-GENE as part of the OVOGENAE program. C.P. was supported by the Cancéropôle Grand Ouest, the LNCC, and the ARC.

Correspondence: ²Svetlana Uzbekova, UMR 6175 INRA-CNRS-Université de Tours Station Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France. FAX: 33 2 47 42 77 43; e-mail: uzbekova{at}tours.inra.fr