胎盘是哺乳动物母体与胚胎之间的联结和屏障，是胚胎发育必不可少的重要器官。母体与胎儿的血液系统在胎盘的Labyrinth层进行物质交换，而SynT细胞是Labyrinth层的具体屏障细胞。目前人们对SynT细胞的分化和Labyrinth层的发育机制了解非常有限。细胞转录因子Ovol2的基因敲除导致小鼠胚胎在胎盘发育，血管生成，心脏发育等方面都有缺陷。但其在胎盘中的原发性功能没有研究。申请人的前期工作发现Ovol2特异性的表达在小鼠胎盘的Labyrinth层，并且随TSCs细胞分化表达上调，过表达或基因敲除Ovol2影响SynT细胞的标记基因Syn-A的表达，表明Ovo2在SynT细胞的分化过程中有功能。本项目将利用慢病毒感染方法特异性的敲除Ovol2在滋养外胚层中的表达，以研究Ovol2在小鼠胎盘中的原发性功能，探索SynT细胞分化与胎盘Labyrinth层的发育机制。

Placenta, an essential organ for embryonic development, is the barrier and connection tissue between mammalian mother and fetus. The nutrient and gas exchange happens in the placenta labyrinth layer. Syncytiotrophoblast (SynT) cells separate fetal and maternal vasculation system. The current understanding on the mechanism of SynT cell differentiation and labyrinth development is very limited. Knockout zinc-finger transcriptional factor Ovol2 causes embryonic development defects, including placenta development, angiogenesis, heart development etc. However, the primary effect of Ovol2 on placenta development is not yet defined. In our previous study, we found that Ovol2 specifically expressed in placenta labyrinth layer. Upon TSCs differentiation, Ovol2 is significantly upregulated. Moreover, overexpression of Ovol2 induces SynT cell marker SynT-A upregulation. Knockout Ovol2 in TSCs represses Syn-A expression upon cell differentiation. All above experiments suggest that Ovol2 has function in SynT cell differentiation. To study the primary effect of Ovol2 in placenta, we plan to use lentivirus infecion method to specifically delete its expression in trophectodermal cells. This study would help us to better understand the mechanism of SynT cell differentiation and labyrinth development.