Couldrey Christine, Wells David N, Lee Rita S F
AgResearch Ltd., Ruakura Research Centre, Hamilton, New Zealand.
Cell Reprogram. 2011 Apr;13(2):171-7. doi: 10.1089/cell.2010.0065.
The cloning of animals by somatic cell nuclear transfer (SCNT) has the potential to allow rapid dissemination of desirable traits from elite animals. However, concern has been expressed that aberrant epigenetic marks in SCNT-derived animals may be passed onto the next generation, even though the offspring of clones appear to be mainly normal. Here, we compared the DNA methylation patterns at 10 genomic regions in sperm from SCNT bulls with that from normal, naturally conceived bulls and with the nuclear donor somatic cells. Eight of the 10 genomic regions were differentially methylated in sperm compared with the donor cell DNA. All three satellite sequences examined here were less methylated in sperm than in the donor cells, contradicting the belief that the sperm genome is always highly methylated. The DNA methylation patterns at all 10 regions were almost identical between SCNT and control sperm, with only one out of the 175 CpG sites/groups of sites examined showing significant difference. These results provide the first molecular evidence that the donor cell genome is correctly reprogrammed upon passage through the germ line in males, and that any epigenetic aberrations harbored by SCNT bulls are unlikely to be passed onto their offspring.
通过体细胞核移植（SCNT）克隆动物有可能使优良动物的理想性状迅速传播。然而，有人担心SCNT衍生动物中的异常表观遗传标记可能会传递给下一代，尽管克隆后代似乎基本正常。在这里，我们比较了SCNT公牛精子中10个基因组区域的DNA甲基化模式与正常自然受孕公牛精子以及核供体体细胞的DNA甲基化模式。与供体细胞DNA相比，10个基因组区域中的8个在精子中存在差异甲基化。这里检测的所有三个卫星序列在精子中的甲基化程度均低于供体细胞，这与精子基因组总是高度甲基化的观点相矛盾。SCNT精子和对照精子在所有10个区域的DNA甲基化模式几乎相同，在所检测的175个CpG位点/位点组中只有1个显示出显著差异。这些结果提供了首个分子证据，表明供体细胞基因组在通过雄性生殖系时被正确重编程，并且SCNT公牛所携带的任何表观遗传异常不太可能传递给它们的后代。
