title: Chorioallantoic placenta defects in cloned mice.
abstract: Somatic cell nuclear transfer technology has been applied to produce live clones successfully in several mammalian species, but the success rates are very low. In mice, about half of the nuclear transfer embryos undergo implantation, but very few survive to term. We undertook detailed histological analyses of placentas from cloned mouse embryos generated from cumulus cells at 10.5 dpc of pregnancy, by which stage most clones have terminated their development. At 10.5 dpc, the extraembryonic tissues displayed several defined histological patterns, each reflecting their stage of developmental arrest. The most notable abnormality was the poor development of the spongiotrophoblast layer of diploid cells. This is in contrast to the placental hyperplasia frequently observed in somatic clones at 12.5 dpc or later stages. A variety of structural abnormalities were also observed in the embryos. Both placental and embryonic defects likely contribute to the low success rate of the mouse clones.
authors.affiliation: Department of Epigenetics, Medical Research Institute, Tokyo Medical and Dental University, 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Wakisaka-Saito
authors.forename: Takashi
authors.initials: T
authors.lastname: Kohda
authors.forename: Kimiko
authors.initials: K
authors.lastname: Inoue
authors.forename: Narumi
authors.initials: N
authors.lastname: Ogonuki
authors.forename: Hiromi
authors.initials: H
authors.lastname: Miki
authors.forename: Takafusa
authors.initials: T
authors.lastname: Hikichi
authors.forename: Eiji
authors.initials: E
authors.lastname: Mizutani
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Wakayama
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kaneko-Ishino
authors.forename: Atsuo
authors.initials: A
authors.lastname: Ogura
authors.forename: Fumitoshi
authors.initials: F
authors.lastname: Ishino
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D049033:Chorioallantoic Membrane / Q000378:metabolism*; D019976:Cloning, Organism / Q000379:methods*; D046149:Embryo Culture Techniques; D047108:Embryonic Development; D005260:Female; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010920:Placenta / Q000378:metabolism*; D010922:Placenta Diseases / Q000235:genetics; D011247:Pregnancy; D011270:Pregnancy, Animal