Requirement for the MAP kinase kinase/MAP kinase cascade in Xenopus oocyte maturation

EMBO J. 1994 May 1;13(9):2131-8.


MAP kinase kinase (MAPKK) has been identified as a protein factor that can induce phosphorylation and activation of inactive MAP kinase in vitro. In this study, we produced an anti-Xenopus MAPKK antibody that can specifically inhibit Xenopus MAPKK activity in vitro. Microinjection of this antibody into immature oocytes prevented progesterone-induced MAP kinase activation. Moreover, progesterone-induced histone H1 kinase activation and germinal vesicle breakdown (GVBD) were inhibited in the oocytes injected previously with this antibody. Furthermore, when a bacterially expressed Mos was introduced into immature oocytes, Mos-induced MAP kinase activation and GVBD were blocked in the oocytes injected with the anti-MAPKK antibody. These results show that MAPKK is responsible for the activation of MAP kinase in vivo and that the MAPKK/MAP kinase cascade plays a pivotal role in the MPF activation during the oocyte maturation process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Antibody Specificity
  • Cell-Free System
  • Enzyme Activation
  • Ethers, Cyclic / pharmacology
  • Microinjections
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase Kinases
  • Okadaic Acid
  • Oocytes / cytology*
  • Oocytes / enzymology
  • Oogenesis*
  • Progesterone / antagonists & inhibitors
  • Progesterone / physiology
  • Protein Kinases / immunology
  • Protein Kinases / metabolism*
  • Protein-Serine-Threonine Kinases / metabolism*
  • Protein-Tyrosine Kinases / metabolism*
  • Signal Transduction
  • Xenopus


  • Antibodies, Monoclonal
  • Ethers, Cyclic
  • Okadaic Acid
  • Progesterone
  • Protein Kinases
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase Kinases