title: A simple method for producing tetraploid porcine parthenogenetic embryos.
abstract: The objective was to produce porcine tetraploid parthenogenetic embryos using cytochalasin B, which inhibits polar body extrusion. Porcine cumulus-enclosed oocytes aspirated from antral follicles were cultured for 51 h, and treated with cytochalasin B from 35 h to 42 h after the start of culture. After maturation culture, 74.7% (2074/2775) of oocytes treated with cytochalasin B did not extrude a polar body (0PB oocytes). In contrast, 80.4% (1931/2403) of control oocytes extruded a polar body (1PB oocytes). The 0PB oocytes were electrically stimulated, treated with cytochalasin B again for 3 h, and then cultured without cytochalasin B. Six days after electrical stimulation, 49.8% (321/644) reached the blastocyst stage. The number of cells in these blastocysts derived from 0PB oocytes was significantly lower than that from 1PB oocytes (0PB: 24.9 ± 10.6; 1PB: 43.0 ± 17.1; mean ± SD). A porcine chromosome 1-specific sequence was detected in parthenogenetic 0PB embryos by fluorescence in situ hybridization (FISH) analysis. Typical pronucleus-stage samples derived from 0PB embryos had two pronuclei, each with two signals. In two-cell and blastocyst-stage embryos, four signals were detected in each nucleus derived from 0PB embryos. We inferred that 0PB oocytes, which had a tetraploid number of chromosomes, started to develop as tetraploid parthenotes after electrical stimulation, and that tetraploid status was stably maintained during early embryonic development, at least until the blastocyst stage.
authors.affiliation: Transgenic Animal Research Center, National Institute of Agrobiological Sciences, Ibaraki, Japan. senbon@affrc.go.jp
authors.forename: S
authors.initials: S
authors.lastname: Sembon
authors.forename: D
authors.initials: D
authors.lastname: Fuchimoto
authors.forename: M
authors.initials: M
authors.lastname: Iwamoto
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Yoshioka
authors.forename: A
authors.initials: A
authors.lastname: Onishi
mesh_terms: D000818:Animals; D016009:Chi-Square Distribution; D003571:Cytochalasin B / Q000494:pharmacology*; D004558:Electric Stimulation / Q000379:methods; D046149:Embryo Culture Techniques / Q000379:methods / Q000662:veterinary*; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D017404:In Situ Hybridization, Fluorescence / Q000662:veterinary; D008540:Meiosis / Q000502:physiology; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D010312:Parthenogenesis / Q000502:physiology*; D011247:Pregnancy; D013552:Swine / Q000196:embryology / Q000235:genetics / Q000502:physiology*; D057891:Tetraploidy
chemical_list: D003571:Cytochalasin B