title: RO-3306 prevents postovulatory aging-mediated spontaneous exit from M-II arrest in rat eggs cultured in vitro.
abstract: BACKGROUND
  Postovulatory aging-mediated spontaneous exit from metaphase-II (M-II) arrest deteriorates egg quality and limits assisted reproductive technologies outcome (ART) outcome. Present study was aimed to find out whether RO-3306, specific cyclin dependent kinase 1 (Cdk1) inhibitor could protect against postovulatory aging-mediated spontaneous exit from M-II arrest in rat eggs cultured in vitro.
  
  
  METHODS
  Freshly ovulated M-II arrested eggs were exposed to various concentrations of RO-3306 for 3h in vitro. The morphological changes, percentage of spontaneous exit from M-II arrest, total and specific phosphorylation status of Cdk1, cyclin B1 level and Cdk1 activity were analyzed.
  
  
  RESULTS
  Data suggest that RO-3306 protected postovulatory aging-mediated spontaneous exit from M-II arrest in a concentration-dependent manner. Postovulatory aging increased Thr14/Tyr15 phosphorylated Cdk1 level, decreased Thr161 phosphorylated Cdk1 as well as cyclin B1 levels and increased Cdk1 activity in aged eggs cultured in vitro. On the other hand, RO-3306 protected postovulatory aging-induced changes in specific phosphorylation of Cdk1, cyclin B1 level, inhibited the kinase activity and prevented spontaneous exit from M-II arrest.
  
  
  CONCLUSIONS
  Our results suggest that postovulatory aging destabilizes MPF by modulating specific phosphorylation of Cdk1 and cyclin B1 level. RO-3306 prevented these changes and maintained M-II arrest in rat eggs cultured in vitro. Hence, maintenance of M-II arrest in ovulated eggs using RO-3306 could be beneficial to increase the number of eggs available for various ART programs.
authors.affiliation: Cell Physiology Laboratory, Biochemistry Unit, Department of Zoology, Banaras Hindu University, Varanasi 221005, UP, India.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Prasad
authors.affiliation: Genotoxicology and Cancer Biology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221005, UP, India.
authors.forename: Biplob
authors.initials: B
authors.lastname: Koch
authors.affiliation: Cell Physiology Laboratory, Biochemistry Unit, Department of Zoology, Banaras Hindu University, Varanasi 221005, UP, India. Electronic address: shailchaubey@gmail.com.
authors.forename: Shail K
authors.initials: SK
authors.lastname: Chaube
mesh_terms: D000375:Aging / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D056744:Cyclin B1 / Q000378:metabolism; D005260:Female; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects*; D008677:Metaphase / Q000187:drug effects*; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D010060:Ovulation / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D010769:Phosphothreonine / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology*; D051381:Rats; D013844:Thiazoles / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D056744:Cyclin B1; D011804:Quinolines; C512984:RO 3306; D013844:Thiazoles; D051028:bcl-2-Associated X Protein; D010769:Phosphothreonine; D016203:CDC2 Protein Kinase
keywords: ART; Cdk1; MPF; Postovulatory egg aging; SEA