title: Cycloheximide-induced activation of mouse eggs: effects on cdc2/cyclin B and MAP kinase activities.
abstract: Fertilization of metaphase II-arrested mouse eggs results in resumption of meiosis and a decrease in both cdc2/cyclin B kinase and MAP kinase activities; the decrease in cdc2/cyclin B kinase activity precedes the decrease in MAP kinase activity. Cycloheximide treatment of metaphase II-arrested mouse eggs also results in resumption of meiosis but bypasses the fertilization-induced Ca2+ transient. However, it is not known if cycloheximide treatment results in the same temporal changes in cdc2/cyclin B kinase and MAP kinase activities that are intimately associated with resumption of meiosis. We report that cycloheximide-treated mouse eggs manifest similar temporal changes in the decrease in both cdc2/cyclin B kinase and MAP kinase activities that occur following fertilization, although cortical granule exocytosis is not stimulated. The decrease in cdc2/cyclin B kinase activity, however, does not seem to be required for the decrease in MAP kinase activity, since the decrease in MAP kinase activity still occurs in cycloheximide-treated eggs that are also incubated in the presence of nocodazole, which inhibits cyclin B degradation and hence the decrease in cdc2/cyclin B kinase. Following removal of these drugs, cdc2/cyclin B kinase activity remains high, MAP kinase activity increases to levels similar to that in the metaphase II-arrested eggs, and a spindle(s) forms with the chromosomes aligned on a metaphase plate. Results of these experiments suggest that some other protein with a relatively short half-life, e.g. cmos, a known upstream activator of MAP kinase, may be responsible for events leading to the decrease in MAP kinase activity.
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: J
authors.initials: J
authors.lastname: Moos
authors.forename: G S
authors.initials: GS
authors.lastname: Kopf
authors.forename: R M
authors.initials: RM
authors.lastname: Schultz
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002843:Chromatin / Q000187:drug effects; D019926:Cyclin B; D056744:Cyclin B1; D016213:Cyclins / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology*; D004261:DNA Replication / Q000187:drug effects; D004527:Egg Proteins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006207:Half-Life; D016200:Maturation-Promoting Factor / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D015739:Nocodazole / Q000494:pharmacology; D019319:Okadaic Acid / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects* / Q000201:enzymology; D010766:Phosphorylation; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins
chemical_list: C534700:Ccnb1 protein, mouse; D002843:Chromatin; D019926:Cyclin B; D056744:Cyclin B1; D016213:Cyclins; D004527:Egg Proteins; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; D019319:Okadaic Acid; D003513:Cycloheximide; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D016200:Maturation-Promoting Factor; D001973:Bromodeoxyuridine; D015739:Nocodazole