title: Maturation promoting factor destabilization facilitates postovulatory aging-mediated abortive spontaneous egg activation in rat.
abstract: The present study was designed to investigate whether destabilization of maturation promoting factor (MPF) leads to postovulatory aging-mediated abortive spontaneous egg activation (SEA). If so, we wished to determine whether changes in Wee-1 as well as Emi2 levels are associated with MPF destabilization during postovulatory aging-mediated abortive SEA in rats eggs aged in vivo. For this purpose, sexually immature female rats were given a single injection (20 IU IM) of pregnant mare serum gonadotropin for 48 h followed by single injection of human chorionic gonadotropin (20 IU). Ovulated eggs were collected after 14, 17, 19 and 21 h post-hCG surge to induce postovulatory aging in vivo. The morphological changes, Wee1, phosphorylation status of cyclin dependent kinase 1(Cdk1), early mitotic inhibitor 2 (Emi2), anaphase promoting complex/cyclosome (APC/C), cyclin B1, mitotic arrest deficient protein (MAD2) levels and Cdk1 activity were analyzed. The increased Wee 1 level triggered phosphorylation of Thr-14/Tyr-15 and dephosphorylation of Thr-161 residues of Cdk1. The decrease of Emi2 level was associated with increased APC/C level and decreased cyclin B1 level. Changes in phosphorylation status of Cdk1 and reduced cyclin B1 level resulted in destabilization of MPF. The destabilized MPF finally led to postovulatory aging-mediated abortive SEA in rat eggs. It was concluded that the increase of Wee 1 but decrease of Emi2 level triggers MPF destabilization and thereby postovulatory aging-mediated abortive SEA in rat eggs.
authors.affiliation: Department of Zoology, Biochemistry Unit, Cell Physiology Laboratory, Varanasi, 221005, U.P., India.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Prasad
authors.affiliation: Department of Zoology, Genotoxicology and Cancer Biology Laboratory, Institute of Science, Banaras Hindu University, Varanasi, 221005, U.P., India.
authors.forename: Biplob
authors.initials: B
authors.lastname: Koch
authors.affiliation: Department of Zoology, Biochemistry Unit, Cell Physiology Laboratory, Varanasi, 221005, U.P., India.
authors.forename: Shail K
authors.initials: SK
authors.lastname: Chaube
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D016922:Cellular Senescence / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D056744:Cyclin B1 / Q000378:metabolism; D044783:F-Box Proteins / Q000378:metabolism; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology; D006736:Horses; D006801:Humans; D064246:Mad2 Proteins / Q000378:metabolism; D016200:Maturation-Promoting Factor / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D010060:Ovulation / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D013912:Threonine / Q000378:metabolism; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin; D056744:Cyclin B1; C546111:Emi2 protein, rat; D044783:F-Box Proteins; D006064:Gonadotropins, Equine; D064246:Mad2 Proteins; D013912:Threonine; D064173:Anaphase-Promoting Complex-Cyclosome; C000605789:Wee1 protein, rat; D011505:Protein-Tyrosine Kinases; D016203:CDC2 Protein Kinase; D016200:Maturation-Promoting Factor
keywords: Emi2; Wee1; anaphase promoting complex/cyclosome; maturation promoting factor; postovulatory egg aging