title: Induction of metaphase arrest in cleaving Xenopus embryos by the protein kinase p90Rsk.
abstract: Before fertilization, vertebrate eggs are arrested in metaphase of meiosis II by cytostatic factor (CSF), an activity that requires activation of the mitogen-activated protein kinase (MAPK) pathway. To investigate whether CSF arrest is mediated by the protein kinase p90Rsk, which is phosphorylated and activated by MAPK, a constitutively activated (CA) form of Rsk was expressed in Xenopus embryos. Expression of CA Rsk resulted in cleavage arrest, and cytological analysis showed that arrested blastomeres were in M phase with prominent spindles characteristic of meiotic metaphase. Thus, Rsk appears to be the mediator of MAPK-dependent CSF arrest in vertebrate unfertilized eggs.
authors.affiliation: Howard Hughes Medical Institute and Department of Pharmacology, University of Colorado School of Medicine, Denver, CO 80262, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Gross
authors.forename: M S
authors.initials: MS
authors.lastname: Schwab
authors.forename: A L
authors.initials: AL
authors.lastname: Lewellyn
authors.forename: J L
authors.initials: JL
authors.lastname: Maller
mesh_terms: D064413:3-Phosphoinositide-Dependent Protein Kinases; D000818:Animals; D001757:Blastomeres / Q000166:cytology* / Q000201:enzymology; D004789:Enzyme Activation; D020935:MAP Kinase Signaling System; D008540:Meiosis; D008677:Metaphase; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009865:Oocytes / Q000166:cytology / Q000201:enzymology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017231:Proto-Oncogene Proteins c-mos / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000648:ultrastructure; D014981:Xenopus
chemical_list: D012333:RNA, Messenger; D011994:Recombinant Proteins; D064413:3-Phosphoinositide-Dependent Protein Kinases; D017346:Protein Serine-Threonine Kinases; D017231:Proto-Oncogene Proteins c-mos; D019893:Ribosomal Protein S6 Kinases; D020928:Mitogen-Activated Protein Kinases