title: Effects of cycloheximide treatment and interval between fusion and activation on in vitro development of pig nuclear transfer embryos.
abstract: The effects of cycloheximide (CHX) treatment and the interval between fusion and activation on the development of pig nuclear transfer (NT) embryos constructed with enucleated oocytes and serum-starved granulosa/cumulus cells were examined. One group of couplets was fused and activated simultaneously (FAS) by a single electrical pulse (activation pulse). Another three groups of couplets were fused electricaly 1.5, 2.5 or 4.5 h before being subjected to the activation pulse (FBA). Each group was divided into two subgroups and incubated with or without CHX. The NT embryos treated with CHX showed a high and stable cleavage rate, regardless of the interval between fusion and activation; however, development to blastocysts was improved only when the NT embryos were subjected to FAS with CHX. These results indicate that CHX-sensitive events occurring shortly after FAS may be responsible for the development to blastocysts. Fusion pulse rarely activated M II oocytes, but rapidly dropped the p34cdc2 kinase activity in NT embryos. A pronucleus-like structure was observed 2-2.5 h after the activation pulse with CHX in NT embryos of both the FAS and FBA groups. Therefore, successive inactivation of M-phase promoting factor and cytostatic factor at a certain short interval may also play an important role in the development of NT embryos.
authors.affiliation: Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: M A
authors.initials: MA
authors.lastname: Martinez Diaz
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology; D016203:CDC2 Protein Kinase / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology*; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D005260:Female; D006107:Granulosa Cells / Q000648:ultrastructure; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000648:ultrastructure*; D006080:Ovarian Follicle / Q000648:ultrastructure; D013552:Swine / Q000196:embryology*
chemical_list: D003513:Cycloheximide; D016203:CDC2 Protein Kinase