Fine mapping of genome activation in bovine embryos by RNA sequencing
Fine mapping of genome activation in bovine embryos by RNA sequencing
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DOI：
10.1073/pnas.1321569111
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发表时间：
2014-03-18
影响因子：
11.1
通讯作者：
Wolf, Eckhard
中科院分区：
文献类型：
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作者：
Graf, Alexander;Krebs, Stefan;Wolf, Eckhard
在母体向胚胎过渡的过程中，胚胎发育的控制逐渐从储存在卵母细胞中的母体rna和蛋白质转向胚胎基因组激活（EGA）后产生的基因产物。对胚胎转录开始的详细了解被母体转录本的存在所掩盖。利用牛模型系统，我们通过RNA测序建立了生发囊泡和中期卵母细胞，以及4细胞、8细胞、16细胞和囊胚期胚胎的转录本的全面目录。这些基因是通过牛卵母细胞与牛精子的体外受精产生的，以便于对亲本特异性转录组进行分析。在不同发育阶段检测到12.4 ~ 13.7 × 10(3)个不同基因的转录本。EGA是通过(i)检测胚胎转录本来分析的，这些转录本不存在于卵母细胞中；（ii）检测来自父本等位基因的转录本；（iii）内含子序列初级转录本的检测。这些策略揭示了(i) 220、（ii） 937和（iii） 6848个基因从四细胞到囊胚阶段被激活。基因激活比例最大[i]。e, (i) 59%, (ii) 42%, (iii) 58%]在8细胞胚胎中发现，表明这一阶段主要存在EGA。对四细胞阶段激活的基因进行基因本体分析，确定了与RNA加工、翻译和转运相关的类别，与主要EGA的准备一致。我们的研究提供了牛卵母细胞成熟和早期胚胎发育的最大转录组数据集，并详细了解了特定基因的胚胎激活时间。
During maternal-to-embryonic transition control of embryonic development gradually switches from maternal RNAs and proteins stored in the oocyte to gene products generated after embryonic genome activation (EGA). Detailed insight into the onset of embryonic transcription is obscured by the presence of maternal transcripts. Using the bovine model system, we established by RNA sequencing a comprehensive catalogue of transcripts in germinal vesicle and metaphase II oocytes, and in embryos at the four-cell, eight-cell, 16-cell, and blastocyst stages. These were produced by in vitro fertilization of Bos taurus taurus oocytes with sperm from a Bos taurus indicus bull to facilitate parent-specific transcriptome analysis. Transcripts from 12.4 to 13.7 x 10(3) different genes were detected in the various developmental stages. EGA was analyzed by (i) detection of embryonic transcripts, which are not present in oocytes; (ii) detection of transcripts from the paternal allele; and (iii) detection of primary transcripts with intronic sequences. These strategies revealed (i) 220, (ii) 937, and (iii) 6,848 genes to be activated from the four-cell to the blastocyst stage. The largest proportion of gene activation [i. e., (i) 59%, (ii) 42%, and (iii) 58%] was found in eight-cell embryos, indicating major EGA at this stage. Gene ontology analysis of genes activated at the four-cell stage identified categories related to RNA processing, translation, and transport, consistent with preparation for major EGA. Our study provides the largest transcriptome data set of bovine oocyte maturation and early embryonic development and detailed insight into the timing of embryonic activation of specific genes.