title: Reprogramming of bovine somatic cell nuclei is not directly regulated by maturation promoting factor or mitogen-activated protein kinase activity.
abstract: Cloned mammals with normal fertility have been produced by nuclear transfer. Thus, oocyte cytoplasm has the ability to convert differentiated somatic cell nuclei into a state that resembles the conditions that occur at fertilization (nuclear reprogramming). Despite the long-held assumption that reprogramming factors are present in mammalian oocytes, the molecular nature of these factors is not known. The present study demonstrates that the process of nuclear reprogramming is not directly regulated by maturation promoting factor or mitogen-activated protein kinase activity. The potential for nuclear-transferred oocytes to develop to the blastocyst stage was not different when somatic cells at the M phase were fused with oocytes activated with ionomycin and cycloheximide 1-5 h before (12%-22%) but was significantly decreased when oocytes were activated 6 h before (1%). Further molecular studies on the differences between oocytes with and without reprogramming potential are required and will be useful for the identification of reprogramming factors.
authors.affiliation: Laboratory of Animal Reproduction, College of Agriculture, Kinki University, Nara, 631-8505, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tani
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kato
authors.forename: Yukio
authors.initials: Y
authors.lastname: Tsunoda
mesh_terms: D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002417:Cattle; D002459:Cell Fusion; D002467:Cell Nucleus / Q000187:drug effects*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D015759:Ionomycin / Q000494:pharmacology; D016200:Maturation-Promoting Factor / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008938:Mitosis; D009570:Nitriles / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010312:Parthenogenesis
chemical_list: D002070:Butadienes; D004791:Enzyme Inhibitors; D009570:Nitriles; C113580:U 0126; D015759:Ionomycin; D003513:Cycloheximide; D016200:Maturation-Promoting Factor; D020928:Mitogen-Activated Protein Kinases