Retrotransposon expression as a defining event of genome reprograming in fertilized and cloned bovine embryos
Retrotransposon expression as a defining event of genome reprograming in fertilized and cloned bovine embryos
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DOI：
10.1530/rep-09-0042
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发表时间：
2009-08-01
期刊：
影响因子：
3.8
通讯作者：
Duranthon, V.
中科院分区：
文献类型：
--
作者：
Bui, L. C.;Evsikov, A. V.;Duranthon, V.
基因组重编程是细胞核在新环境中改变其表观遗传特征和基因表达模式的能力。哺乳动物克隆的低效率是由于卵母细胞体细胞核移植（SCNT）后基因组重编程的不完全性和异常性。迄今为止，对SCNT后足月发育至关重要的基因组重编程方面仍然知之甚少。为了确定这一过程的关键因素，我们使用一种专门用于牛胚胎基因组转录激活的新cDNA阵列，比较了正常牛胚胎母系到胚胎过渡过程中基因表达的变化，以及供体细胞和SCNT胚胎之间基因表达的变化。在体细胞重编程过程中，三组转录本受影响最大：内源性末端重复（LTR）反转录转座子和线粒体转录本上调，而编码核糖体蛋白的基因下调。这些意想不到的数据证明了对体细胞重编程最敏感的转录本的特定类别，并可能影响SCNT胚胎的生存能力。重要的是，LTR逆转录转座子的大量转录激活导致SCNT和受精胚胎中它们的转录水平相似。综上所述，这些结果为理解卵母细胞细胞质驱动的核重编程开辟了一条新的途径。生殖（2009）138 289-299
Genome reprograming is the ability of a nucleus to modify its epigenetic characteristics and gene expression pattern when placed in a new environment. Low efficiency of mammalian cloning is attributed to the incomplete and aberrant nature of genome reprograming after somatic cell nuclear transfer (SCNT) in oocytes. To date, the aspects of genome reprograming critical for full-term development after SCNT remain poorly understood. To identify the key elements of this process, changes in gene expression during maternal-to-embryonic transition in normal bovine embryos and changes in gene expression between donor cells and SCNT embryos were compared using a new cDNA array dedicated to embryonic genome transcriptional activation in the bovine. Three groups of transcripts were mostly affected during somatic reprograming: endogenous terminal repeat (LTR) retrotransposons and mitochondrial transcripts were up-regulated, while genes encoding ribosomal proteins were downregulated. These unexpected data demonstrate specific categories of transcripts most sensitive to somatic reprograming and likely affecting viability of SCNT embryos. Importantly, massive transcriptional activation of LTR retrotransposons resulted in similar levels of their transcripts in SCNT and fertilized embryos. Taken together, these results open a new avenue in the quest to understand nuclear reprograming driven by oocyte cytoplasm. Reproduction (2009) 138 289-299