1. MAP Kinase Inactivation Is Required Only for G2–M Phase Transition in Early Embryogenesis Cell Cycles of the StarfishesMarthasterias glacialisandAstropecten aranciacus
- Author
-
Stephen M. Keyse, Daniel Fisher, Valérie Vergé, Marcel Dorée, André Picard, Marie-Noëlle Simon, and Ariane Abrieu
- Subjects
DNA Replication ,G2 Phase ,Parthenogenesis ,Mitosis ,Fungal Proteins ,Starfish ,Mitotic cell cycle ,Dual Specificity Phosphatase 6 ,MAP2K1 ,Animals ,RNA, Messenger ,Egtazic Acid ,Molecular Biology ,MAPK14 ,Sequence Deletion ,Centrosome ,Cyclin-dependent kinase 1 ,biology ,MAP kinase kinase kinase ,Ionophores ,Adenine ,Cyclin-dependent kinase 2 ,Cyclin-dependent kinase 3 ,Cell Biology ,Molecular biology ,Cell biology ,Meiosis ,Fertilization ,Calcium-Calmodulin-Dependent Protein Kinases ,biology.protein ,Oocytes ,Schizosaccharomyces pombe Proteins ,Cyclin-dependent kinase 7 ,Protein Tyrosine Phosphatases ,Transcription Factors ,Developmental Biology - Abstract
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-ΔN, 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.
- Full Text
- View/download PDF