MAP kinase inactivation is required only for G2-M phase transition in early embryogenesis cell cycles of the starfishes Marthasterias glacialis and Astropecten aranciacus.
Downregulation of MAP kinase is a universal consequence of fertilization in the animal kingdom. Here we show that oocytes of the starfishes Astropecten aranciacus and Marthasterias glacialis complete meiotic maturation and form a pronucleus when treated with 1-methyladenine and then complete DNA replication and arrest at G2 if not fertilized. Release of G2 by fertilization or a variety of parthenogenetic treatments is associated with inactivation of MAP kinase. Prevention of MAP kinase inactivation by microinjection of Ste11-DeltaN, a constitutively active budding yeast MAP kinase kinase kinase, arrests fertilized eggs at G2 in either the first or the second mitotic cell cycle, in a dose-dependent manner. G1 arrest is never observed. Conversely, inactivation of MAP kinase by microinjection of the MAP kinase-specific phosphatase Pyst-1 releases mature starfish oocytes from G2 arrest. The role of MAP kinase in arresting cell cycle at various stages in oocytes of different animal species is discussed.
CRBM CNRS ERS 155, 1919 route de mende, Montpellier cedex 5, 34293, France.
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D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D018385:Centrosome; D004261:DNA Replication; D054642:Dual Specificity Phosphatase 6; D004533:Egtazic Acid / Q000494:pharmacology; D005306:Fertilization; D005656:Fungal Proteins / Q000235:genetics / Q000494:pharmacology; D016195:G2 Phase / Q000502:physiology*; D007476:Ionophores / Q000494:pharmacology; D008540:Meiosis / Q000502:physiology; D008938:Mitosis / Q000502:physiology; D009865:Oocytes; D010312:Parthenogenesis; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D012333:RNA, Messenger / Q000494:pharmacology; D029702:Schizosaccharomyces pombe Proteins; D017384:Sequence Deletion; D013215:Starfish / Q000196:embryology* / Q000201:enzymology; D014157:Transcription Factors / Q000235:genetics / Q000494:pharmacology
D005656:Fungal Proteins; D007476:Ionophores; D012333:RNA, Messenger; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C071596:ste11 protein, S pombe; C008407:1-methyladenine; D004533:Egtazic Acid; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D054642:Dual Specificity Phosphatase 6; D017027:Protein Tyrosine Phosphatases; D000225:Adenine