Department of Biological Sciences, University of Cyprus, University Campus, PO Box 20537, Nicosia 1678, Cyprus.
Nat Commun. 2013;4:1658. doi: 10.1038/ncomms2646.
Although extraembryonic ectoderm trophoblast signals the embryo for primitive streak initiation, a prerequisite for gastrulation, it is unknown whether it also signals for the progression of gastrulation after primitive streak initiation. Here, using Ets2-/- mice, we show that trophoblast signalling is also required in vivo for primitive streak elongation, completion of intraembryonic mesoderm epithelial-mesenchymal transition and the development of anterior primitive streak derivatives such as the node. We show that Ets2-dependent trophoblast signalling is required for the maintenance of high levels of Nodal and Wnt3 expression in the epiblast and for the induction of Snail expression in the primitive streak, between embryonic day 6.3 and 6.7. Within extraembryonic ectoderm trophoblast, Ets2 maintains the expression of the transcription factors Elf5, Cdx2 and Eomes, and that of the signalling molecule Bmp4. We propose a model that provides a genetic explanation as to how Ets2 in trophoblast mediates the progression of gastrulation within the epiblast.
虽然胚外外胚层滋养层信号向胚胎发出原始条纹起始的信号，这是原肠作用的前提，但尚不清楚它是否也向原肠作用的进展发出信号。在这里，我们使用 Ets2-/- 小鼠表明，滋养层信号在体内对于原始条纹伸长、胚胎内中胚层上皮-间充质转化的完成以及前原始条纹衍生物（如节点）的发育也是必需的。我们表明，Ets2 依赖性滋养层信号对于维持高水平的 Nodal 和 Wnt3 在胚外上皮层中的表达以及在胚胎第 6.3 天至 6.7 天之间的原始条纹中诱导 Snail 表达是必需的。在胚外外胚层滋养层中，Ets2 维持转录因子 Elf5、Cdx2 和 Eomes 的表达以及信号分子 Bmp4 的表达。我们提出了一个模型，该模型提供了一个遗传解释，说明滋养层中的 Ets2 如何介导胚外上皮层中原肠作用的进展。
