Nuclear reprogramming in embryos generated by the transfer of yak (Bos grunniens) nuclei into bovine oocytes and comparison with bovine-bovine SCNT and bovine IVF embryos.
Although inter-species SCNT may be useful for increasing and preserving populations of endangered species, there are many reports that inter-species nuclear transfer embryos only develop to the blastocyst stage. In this study, yak-bovine SCNT blastocysts were successfully implanted in the surrogate bovine uterus but failed to develop to term or aborted. To clarify the reasons, we examined yak-bovine SCNT blastocyst development, total cell number, inner cell mass (ICM) number, trophoblast (TE) cell number and relative gene expression in yak fibroblast cells and yak-bovine SCNT embryos at various stages. The potential for development of yak-bovine SCNT embryos to blastocysts was 30+/-5.7% (mean+/-S.E.M.); the total cell number was 85.3+/-16.3, fewer than in IVF bovine embryos (106.2+/-18.2) but within the reported range (60-300). The yak-bovine SCNT blastocysts had a lower ratio of TE cells to total cells (43.9+/-8.7%) than bovine IVF embryos (59.4+/-3.4%; P<0.05) or bovine-bovine SCNT (69.5+/-5.4%; P<0.05). Also, several yak-bovine SCNT embryos had abnormal initiation of expression of both Mash2 and IL6. However, expression of vimentin, collagen, Cx43 and PSMC3 were normal in yak fibroblast cells and yak-bovine SCNT embryos. In conclusion, we inferred that the normal allocation of ICM and TE cells in yak-bovine SCNT embryos and embryo-specific gene reprogramming may be important for successful inter-species animal cloning.
Li
Y
Y
The State Key Laboratory of Agriobiotechnology, China Agricultural University, Yuanmingyuan West Road 2, 100094 Beijing, PR China.
Li
S
S
Dai
Y
Y
Du
W
W
Zhao
C
C
Wang
L
L
Wang
H
H
Li
R
R
Liu
Y
Y
Wan
R
R
Li
N
N
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D002417:Cattle; D002460:Cell Line; D002467:Cell Nucleus; D019976:Cloning, Organism / Q000379:methods*; D003094:Collagen / Q000235:genetics; D018031:Connexin 43 / Q000235:genetics; D004624:Embryo Transfer / Q000662:veterinary; D004622:Embryo, Mammalian / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D047109:Fetal Development; D005347:Fibroblasts; D015870:Gene Expression; D053652:Nuclear Transfer Techniques / Q000662:veterinary*; D009865:Oocytes / Q000648:ultrastructure*; D011247:Pregnancy; D014746:Vimentin / Q000235:genetics
D018031:Connexin 43; D014746:Vimentin; D003094:Collagen