Requirement for the MAP kinase kinase/MAP kinase cascade in Xenopus oocyte maturation.
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.
Kosako
H
H
Department of Genetics and Molecular Biology, Kyoto University, Japan.
Gotoh
Y
Y
Nishida
E
E
D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D002474:Cell-Free System; D004789:Enzyme Activation; D004988:Ethers, Cyclic / Q000494:pharmacology; D008845:Microinjections; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D019319:Okadaic Acid; D009865:Oocytes / Q000166:cytology* / Q000201:enzymology; D009866:Oogenesis; D011374:Progesterone / Q000037:antagonists & inhibitors / Q000502:physiology; D011494:Protein Kinases / Q000276:immunology / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D014981:Xenopus
D000911:Antibodies, Monoclonal; D004988:Ethers, Cyclic; D019319:Okadaic Acid; D011374:Progesterone; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases