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Manipulation and In Vitro Maturation of Xenopus laevis Oocytes, Followed by Intracytoplasmic Sperm Injection, to Study Embryonic Development
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How does Xenopus oocyte acquire its competence to undergo meiotic maturation?

Catherine Jessus1, René Ozon

  • 1Laboratoire de Biologie du Développement, UMR-CNRS 7622, Université Pierre et Marie Curie, boîte 24, 4 place Jussieu, 75252 Paris cédex 05, France.

Biology of the Cell
|June 9, 2004
PubMed

Insights

Maturation-promoting factor (MPF) activation in Xenopus oocytes involves a molecular network that is established during late oogenesis. This network enables the oocyte to respond to progesterone and trigger MPF autoamplification.

Area of Science:

  • Cellular biology
  • Developmental biology
  • Molecular biology

Background:

  • Xenopus oocytes arrest in meiotic prophase, accumulating inactive pre-MPF.
  • Pre-MPF, composed of cyclin B2 and Cdc2, is kept inactive by inhibitory phosphorylation.
  • Oocyte maturation requires progesterone-induced MPF activation via a positive feedback loop.

Purpose of the Study:

  • To investigate the progressive establishment of the molecular network for MPF autoamplification during Xenopus oogenesis.
  • To understand the temporal regulation of MPF activation competence.

Main Methods:

  • Experimental analysis of molecular events during late Xenopus oogenesis.
  • Biochemical assays to monitor pre-MPF accumulation and activation states.

Main Results:

  • The molecular network facilitating MPF autoamplification is progressively assembled during late oogenesis.
  • Oocyte competence to activate MPF in response to progesterone correlates with the establishment of this network.

Conclusions:

  • The autoamplification loop of MPF is not immediately available but is gradually set up during oocyte maturation.
  • This progressive establishment ensures timely and regulated MPF activation for successful meiotic progression.

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