Quantitative analysis of mitochondrial DNAs in macaque embryos reprogrammed by rabbit oocytes.
In cloned animals where somatic cell nuclei and oocytes are from the same or closely related species, the mitochondrial DNA (mtDNA) of the oocyte is dominantly inherited. However, in nuclear transfer (NT) embryos where nuclear donor and oocyte are from two distantly related species, the distribution of the mtDNA species is not known. Here we determined the levels of macaque and rabbit mtDNAs in macaque embryos reprogrammed by rabbit oocytes. Quantification using a real-time PCR method showed that both macaque and rabbit mtDNAs coexist in NT embryos at all preimplantation stages, with maternal mtDNA being dominant. Single NT embryos at the 1-cell stage immediately after fusion contained 2.6 x 10(4) copies of macaque mtDNA and 1.3 x 10(6) copies of rabbit mtDNA. Copy numbers of both mtDNA species did not change significantly from the 1-cell to the morula stages. In the single blastocyst, however, the number of rabbit mtDNA increased dramatically while macaque mtDNA decreased. The ratio of nuclear donor mtDNA to oocyte mtDNA dropped sharply from 2% at the 1-cell stage to 0.011% at the blastocyst stage. These results suggest that maternal mtDNA replicates after the morula stage.
Yang
Cai-Xia
CX
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 25 Bei Si Huan Xi Lu, Haidian, Beijing 100080, China.
Kou
Zhao-Hui
ZH
Wang
Kai
K
Jiang
Yan
Y
Mao
Wen-Wei
WW
Sun
Qing-Yuan
QY
Sheng
Hui-Zhen
HZ
Chen
Da-Yuan
DY
D000818:Animals; D001755:Blastocyst / Q000648:ultrastructure; D002970:Cleavage Stage, Ovum / Q000648:ultrastructure; D004272:DNA, Mitochondrial / Q000648:ultrastructure*; D004622:Embryo, Mammalian / Q000648:ultrastructure*; D005260:Female; D008251:Macaca; D009028:Morula / Q000648:ultrastructure; D053652:Nuclear Transfer Techniques; D009865:Oocytes / Q000648:ultrastructure*; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004272:DNA, Mitochondrial