Deficiency in recapitulation of stage-specific embryonic gene transcription in two-cell stage cloned mouse embryos.
Deficiency in recapitulation of stage-specific embryonic gene transcription in two-cell stage cloned mouse embryos.
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二细胞阶段克隆小鼠胚胎中阶段特异性胚胎基因转录的重演缺陷。
DOI：
10.1002/mrd.20723
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发表时间：
2007
影响因子：
2.5
通讯作者：
Latham,KeithE
中科院分区：
文献类型：
--
作者：
Vassena,Rita;Han,Zhiming;Gao,Shaorong;Latham,KeithE
通过体细胞核移植克隆动物的能力的一个可能的解释是，供体基因组被卵母细胞重新编程，以重现正常的胚胎基因表达模式。小鼠胚胎在两细胞中期显示一组基因（TIG）的瞬时转录诱导，这是胚胎基因组的第一个主要转录产物，特别适合于在任何体外选择发生之前评估卵母细胞是否指导胚胎阶段特异性基因表达程序的正确和有效重演。我们分析了用卵丘细胞核制备的两细胞期克隆中8种TIG的表达。一个未能被转录，和其他七个转录，但支持显着降低mRNA表达。在两细胞中期，减少范围为1.6至17倍，在两细胞晚期，减少范围为1.5至13倍。五个基因在供体细胞中不表达，这些基因表现出最明显的表达缺陷。两个基因在卵丘细胞供体中表达，并支持在此期间其mRNA在克隆中的逐步积累，尽管速率降低。另一个在卵丘细胞中表达的基因在克隆中没有被激活。虽然这些基因中有很大一部分在两细胞期克隆中被重新激活，但这种重演是非常不完美的，发生在一个大大降低的水平上，甚至对一些基因完全没有发生。因此，卵母细胞不能有效地指导早期胚胎阶段特异性基因表达的重演。摩尔Reprod. Dev. 74：1548-1556，2007.© 2007 Wiley利斯公司
One possible explanation to account for the ability to clone animals by somatic cell nuclear transfer is that the donor genome is reprogrammed by the oocyte to recapitulate a normal embryonic pattern of gene expression. Mouse embryos display transient transcriptional induction of a group of genes (TIGs) at the mid two‐cell stage, the first major transcriptional output of the embryonic genome, uniquely suited for evaluating whether the oocyte directs correct and efficient recapitulation of an embryo stage‐specific gene expression program before any in vitro selection occurs. We analyzed the expression of eight TIGs in two‐cell stage clones prepared with cumulus cell nuclei. One failed to be transcribed, and seven others were transcribed, but supported significantly reduced mRNA expression. The reduction ranged from 1.6‐ to 17‐fold at the mid two‐cell stage, and 1.5‐ to 13‐fold for the late two‐cell stage. Five genes were not expressed in the donor cells, and these displayed the most pronounced deficiencies in expression. Two genes were expressed in cumulus cell donors, and supported progressive accumulation of their mRNAs in clones during this period, albeit at reduced rates. One other gene expressed in cumulus cells was not activated in clones. Although a significant proportion of these genes is reactivated in two‐cell stage clones, this recapitulation is grossly imperfect, occurs at a substantially reduced level, and even fails entirely to occur for some genes. Thus, the oocyte is incapable of efficiently directing the recapitulation of early embryonic stage‐specific gene expression. Mol. Reprod. Dev. 74: 1548–1556, 2007. © 2007 Wiley‐Liss, Inc.