Early patterning of cloned mouse embryos contributes to post-implantation development.
Several research groups have suggested that the embryonic-abembryonic (Em-Ab) axis in the mouse can be predicted by the first cleavage plane of the early embryo. Currently, it is not known whether this early patterning occurs in cloned embryos produced by nuclear transfer and whether it affects development to term. In this work, the relationship between the first cleavage plane and the Em-Ab axis was determined by the labeling of one blastomere in cloned mouse embryos at the 2-cell stage, followed by ex-vivo tracking until the blastocyst stage. The results demonstrate that approximately half of the cloned blastocysts had an Em-Ab axis perpendicular to the initial cleavage plane of the 2-cell stage. These embryos were classified as "orthogonal" and the remainder as "deviant". Additionally, we report here that cloned embryos were significantly more often orthogonal than their naturally fertilized counterparts and overexpressed Sox2. Orthogonal cloned embryos demonstrated a higher rate of post-implantation embryonic development than deviant embryos, but cloned pups did not all survive. These results reveal that the angular relationship between the Em-Ab axis and the first cleavage plane can influence later development and they support the hypothesis that proper early patterning of mammalian embryos is required after nuclear transfer.
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Zichuan
Z
Liu
Tang
T
Hai
Xiangpeng
X
Dai
Xiaoyang
X
Zhao
Yingying
Y
Wang
Vincent
V
Brochard
Shuya
S
Zhou
Haifeng
H
Wan
Haijiang
H
Zhang
Liu
L
Wang
Qi
Q
Zhou
Nathalie
N
Beaujean
D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000378:metabolism; D019976:Cloning, Organism; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000166:cytology* / Q000196:embryology* / Q000378:metabolism; D047108:Embryonic Development; D005260:Female; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018613:Microscopy, Confocal; D000071317:Nanog Homeobox Protein; D053652:Nuclear Transfer Techniques; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors / Q000235:genetics
D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse