Laboratory for Embryonic Induction, RIKEN Center for Developmental Biology, Kobe, Hyogo, Japan.
Dev Growth Differ. 2010 Apr;52(3):263-73. doi: 10.1111/j.1440-169X.2009.01158.x. Epub 2010 Jan 20.
During preimplantation mouse development, embryos establish two distinct cell lineages by the time of blastocyst formation: trophectoderm (TE) and inner cell mass (ICM). To explain the mechanism of this cell fate specification, two classical models, namely the inside-outside model and polarity model have been proposed based on experimental manipulation studies on embryos. This review summarizes recent findings on the molecular mechanisms of fate specification, and discusses how these findings fit into the classical models. TE development is regulated by a transcription factor cascade, the core transcription factors of which are Tead4 and Cdx2. The transcriptional activity of Tead4 is regulated by the position-dependent Hippo signaling pathway, thus supporting the inside-outside model. In contrast, several findings support the polarity model; some other findings suggest different mechanisms. We also discuss how the two classical models could be further developed in the light of recent molecular findings.
在植入前的小鼠胚胎发育过程中，胚胎在囊胚形成时建立了两种截然不同的细胞谱系：滋养外胚层 (TE) 和内细胞团 (ICM)。为了解释这种细胞命运特化的机制，基于对胚胎的实验操作研究，提出了两个经典模型，即内外模型和极性模型。本文综述了命运特化的分子机制的最新发现，并讨论了这些发现如何适用于经典模型。TE 的发育受到转录因子级联的调控，核心转录因子是 Tead4 和 Cdx2。Tead4 的转录活性受位置依赖的 Hippo 信号通路的调控，因此支持内外模型。相比之下，一些发现支持极性模型，还有一些发现则表明存在不同的机制。我们还讨论了如何根据最近的分子发现进一步发展这两个经典模型。
