“Interspecies Implantation and Mitochondria Fate of Panda-Rabbit Cloned Embryos”, 2002-08-01 (; similar):
Somatic cell nuclei of giant pandas can dedifferentiate in enucleated rabbit ooplasm, and the reconstructed eggs can develop to blastocysts.
In order to observe whether these interspecies cloned embryos can implant in the uterus of an animal other than the panda, we transferred ~2,300 panda-rabbit cloned embryos into 100 synchronized rabbit recipients, and none became pregnant. In another approach, we co-transferred both panda-rabbit and cat-rabbit interspecies cloned embryos into the oviducts of 21 cat recipients. 14 recipients exhibited estrus within 35 days; 5 recipients exhibited estrus 43–48 days after embryo transfer; and the other 2 recipients died of pneumonia, one of which was found to be pregnant with 6 early fetuses when an autopsy was performed.
Microsatellite DNA analysis of these early fetuses confirmed that 2 were from giant panda-rabbit cloned embryos. The results demonstrated that panda-rabbit cloned embryos can implant in the uterus of a third species, the domestic cat. By using mitochondrial-specific probes of panda and rabbit, we found that mitochondria from both panda somatic cells and rabbit ooplasm coexisted in early blastocysts, but mitochondria from rabbit ooplasm decreased, and those from panda donor cells dominated in early fetuses after implantation.
Our results reveal that mitochondria from donor cells may substitute those from recipient oocytes in post-implanted, interspecies cloned embryos.