How does Xenopus oocyte acquire its competence to undergo meiotic maturation?
During Xenopus oogenesis, the follicle-enclosed oocyte, arrested at the diplotene stage of meiotic prophase, accumulates pre-MPF. Pre-MPF is an heterodimer formed of cyclin B2 and Cdc2 protein kinase, which is maintained inactive by inhibitory phosphorylations on Thr14 and Tyr15. When the oocyte reaches its full size, it becomes competent to respond to progesterone and to activate MPF through a positive feedback loop. In this paper, we present experimental data indicating that the molecular network involved in the autoamplification loop of MPF is progressively established during late oogenesis.
Jessus
Catherine
C
Laboratoire de Biologie du Développement, UMR-CNRS 7622, Université Pierre et Marie Curie, boîte 24, 4 place Jussieu, 75252 Paris cédex 05, France.
Ozon
René
R
D000818:Animals; D016200:Maturation-Promoting Factor / Q000378:metabolism; D008540:Meiosis / Q000502:physiology*; D008954:Models, Biological; D009865:Oocytes / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D009866:Oogenesis / Q000502:physiology; D014981:Xenopus
D016200:Maturation-Promoting Factor