Cormier Sarah, Vandormael-Pournin Sandrine, Babinet Charles, Cohen-Tannoudji Michel
Unité de Biologie du Développement, Institut Pasteur, CNRS URA 2578, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
Gene Expr Patterns. 2004 Oct;4(6):713-7. doi: 10.1016/j.modgep.2004.04.003.
Notch signaling is an evolutionary conserved pathway involved in intercellular signaling and essential for proper cell fate choices during development. Thus, it could be involved in mouse preimplantation development where intercellular signaling plays a crucial role, particularly between the inner cell mass and the trophectoderm of the blastocyst. At their face value, the phenotypes observed when disrupting each of the four Notch genes known in the mouse do not support this view as none of them involves perturbation of preimplantation development. However this could be due to functional redundancy and/or maternal expression. As a first step to address this issue, we decided to examine the expression in early development of various genes known to participate in Notch signaling. Here, we report on the expression pattern of Notch1-4, Jagged1 (Jag1), Jag2, Delta-like1 (Dll-1), Dll-3, Dll-4, Rbpsuh, Deltex1(Dtx1)and Dtx2 genes during preimplantation development from unfertilized eggs until late blastocyst stage using a RT-PCR strategy. We show that Notch1, 2, Jag1-2, Dll-3, Rbpsuh and Dtx2 transcripts are expressed at all stages. Notch4 and Dll-4 mRNAs are synthesized from the 2-cell through to the hatched blastocyst stage. Notch3, Dll-1 and Dtx1exhibit a stage dependent expression as their mRNAs are detected in 2-cell embryos and in hatched blastocysts, but are absent or weakly detected at the morula stage. Finally, we show that all the above genes are expressed both in Embryonic and Trophoblast Stem cells (ES and TS cells, respectively). Our results suggest that the Notch pathway may be active during mouse preimplantation development.
Notch信号通路是一条在进化上保守的通路，参与细胞间信号传导，并且在发育过程中对正确的细胞命运选择至关重要。因此，它可能参与小鼠植入前发育，其中细胞间信号传导起着关键作用，特别是在囊胚的内细胞团和滋养外胚层之间。从表面上看，破坏小鼠中已知的四个Notch基因中的每一个时观察到的表型并不支持这一观点，因为它们中没有一个涉及植入前发育的扰动。然而，这可能是由于功能冗余和/或母体表达。作为解决这个问题的第一步，我们决定研究已知参与Notch信号传导的各种基因在早期发育中的表达。在这里，我们使用RT-PCR策略报告了从未受精卵到晚期囊胚阶段的植入前发育过程中Notch1-4、锯齿状蛋白1（Jag1）、Jag2、Delta样蛋白1（Dll-1）、Dll-3、Dll-4、Rbpsuh、Deltex1（Dtx1）和Dtx2基因的表达模式。我们表明，Notch1、2、Jag1-2、Dll-3、Rbpsuh和Dtx2转录本在所有阶段均有表达。Notch4和Dll-4 mRNA从2细胞期一直合成到孵化囊胚阶段。Notch3、Dll-1和Dtx1表现出阶段依赖性表达，因为它们的mRNA在2细胞胚胎和孵化囊胚中被检测到，但在桑椹胚阶段不存在或检测到的信号较弱。最后，我们表明上述所有基因在胚胎干细胞和滋养层干细胞（分别为ES和TS细胞）中均有表达。我们的结果表明，Notch通路可能在小鼠植入前发育过程中活跃。
