Pluripotent lineage definition in bovine embryos by Oct4 transcript localization
Pluripotent lineage definition in bovine embryos by Oct4 transcript localization
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DOI：
10.1095/biolreprod.104.029322
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发表时间：
2004-11-01
影响因子：
3.6
通讯作者：
McLaughlin, KJ
中科院分区：
文献类型：
--
作者：
Kurosaka, S;Eckardt, S;McLaughlin, KJ
Pou5f1 （Oct4）结构域转录因子Pou5f1 （Oct4）仅限于小鼠的多能性胚胎细胞和种系，是维持小鼠囊胚内细胞群细胞多能性所必需的。尽管小鼠Oct4基因和牛Oct4基因同源物之间的基因组组织和调控区域高度保守，但牛Oct4蛋白并不局限于囊胚期胚胎的内细胞群，这表明Oct4可能不是牛多能性的关键调节因子。我们分析了Oct4转录本在牛卵母细胞和胚胎植入前的时空分布，与蛋白质分布相反，我们发现牛和小鼠之间有很强的保守性。Oct4转录物在牛卵母细胞中低水平存在。与小鼠相似，牛Oct4转录在合子基因组激活后开始一到两个细胞周期，随后在压实后转录急剧增加。在桑葚胚期，Oct4转录本普遍存在于胚胎的所有细胞中；然而，通过原位杂交，在第7天的牛囊胚中，在滋养外胚层中看不到Oct4信号，这表明Oct4在分化过程中的转录下调与小鼠和其他哺乳动物相似。这些结果表明，与蛋白质分布相反，Oct4转录调控在哺乳动物物种之间是保守的。
The POU-domain transcription factor Pou5f1 (Oct4) is restricted to pluripotent embryonic cells and the germ line of the mouse and is required for the maintenance of pluripotency of cells within the inner cell mass of the mouse blastocyst. Despite highly conserved genomic organization and regulatory regions between the mouse Oct4 gene and its bovine orthologue, bovine Oct4 protein is not restricted to the inner cell mass of blastocyst-stage embryos, suggesting that Oct4 may not be a key regulator of pluripotency in the bovine. We analyze the temporal and spatial distribution of Oct4 transcript in bovine oocytes and preimplantation-stage embryos, and in contrast to protein distribution, we find strong conservation between bovine and mouse. Oct4 transcript is present at low levels in the bovine oocyte. Similar to mouse, bovine Oct4 transcription begins one to two cell cycles after zygotic genome activation, followed by a sharp increase in transcription subsequent to compaction. Oct4 transcript is ubiquitously present in all cells of embryos at the morula stage; however, in Day 7 bovine blastocysts, Oct4 signal is not visible in the trophectoderm by in situ hybridization, indicating that transcriptional downregulation of Oct4 on differentiation is similar to that observed in mouse and other mammals. These results indicate that in contrast to protein distribution, regulation of Oct4 transcription is conserved between mammalian species.