Chorioallantoic placenta defects in cloned mice.
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.
Wakisaka-Saito
Noriko
N
Department of Epigenetics, Medical Research Institute, Tokyo Medical and Dental University, 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo 101-0062, Japan.
Kohda
Takashi
T
Inoue
Kimiko
K
Ogonuki
Narumi
N
Miki
Hiromi
H
Hikichi
Takafusa
T
Mizutani
Eiji
E
Wakayama
Teruhiko
T
Kaneko-Ishino
Tomoko
T
Ogura
Atsuo
A
Ishino
Fumitoshi
F
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