title: Improved postimplantation development of rabbit nuclear transfer embryos by activation with inositol 1,4,5-trisphosphate.
abstract: Cloned rabbit embryos are characterized by their extremely poor postimplantation development, despite their high survivability until the blastocyst stage in vitro. This study examined whether the developmental failure of cloned rabbit embryos in vivo can be overcome by technical improvements to the activation protocol. Freshly collected cumulus cells were transferred into enucleated oocytes by intracytoplasmic injection. One to two hours later, the oocytes were activated by electroporation with Ca(2+) or inositol 1,4,5-trisphosphate (IP3), which is known to induce repeated rises in intracellular Ca(2+), as in normal fertilization. After transfer of embryos at the two- to four-cell stages, well-defined implantation sites with remnant fetal tissue were observed at term (day 28) only in the IP3-stimulation groups (0.9% and 5.8% per transferred embryo for single and triple stimulation groups, respectively). When some recipients in the same group were examined at days 16-20, a viable cloned fetus (day 19) with normal organogenesis was obtained. These findings clearly demonstrate that the oocyte activation protocol using IP3 enhances the postimplantation development of nuclear-transferred rabbit embryos.
authors.affiliation: Bioresource Center, RIKEN, Ibaraki, Japan.
authors.forename: Kimiko
authors.initials: K
authors.lastname: Inoue
authors.forename: Narumi
authors.initials: N
authors.lastname: Ogonuki
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Yoko
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Shuji
authors.initials: S
authors.lastname: Takeiri
authors.forename: Kumiko
authors.initials: K
authors.lastname: Nakata
authors.forename: Hiromi
authors.initials: H
authors.lastname: Miki
authors.forename: Mayuko
authors.initials: M
authors.lastname: Kurome
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nagashima
authors.forename: Atsuo
authors.initials: A
authors.lastname: Ogura
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D019976:Cloning, Organism / Q000379:methods; D018274:Electroporation; D004622:Embryo, Mammalian / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000187:drug effects; D011247:Pregnancy; D011817:Rabbits
chemical_list: D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium