Wellcome Trust/Cancer Research UK Gurdon Institute, Cambridge CB2 1QN, UK.
Nat Commun. 2012 Feb 14;3:673. doi: 10.1038/ncomms1671.
The development of an anterior-posterior (AP) polarity is a crucial process that in the mouse has been very difficult to analyse, because it takes place as the embryo implants within the mother. To overcome this obstacle, we have established an in-vitro culture system that allows us to follow the step-wise development of anterior visceral endoderm (AVE), critical for establishing AP polarity. Here we use this system to show that the AVE originates in the implanting blastocyst, but that additional cells subsequently acquire AVE characteristics. These 'older' and 'younger' AVE domains coalesce as the egg cylinder emerges from the blastocyst structure. Importantly, we show that AVE migration is led by cells expressing the highest levels of AVE marker, highlighting that asymmetry within the AVE domain dictates the direction of its migration. Ablation of such leading cells prevents AVE migration, suggesting that these cells are important for correct establishment of the AP axis.
前后（AP）极性的发展是一个关键过程，在小鼠中，由于胚胎在母体内植入，因此很难进行分析。为了克服这一障碍，我们建立了一种体外培养系统，使我们能够逐步研究对建立 AP 极性至关重要的前内脏内胚层（AVE）的发展。在这里，我们使用该系统表明 AVE 起源于植入的囊胚，但随后其他细胞获得了 AVE 的特征。随着卵圆柱从囊胚结构中出现，这些“较老”和“较年轻”的 AVE 区域合并。重要的是，我们表明 AVE 的迁移是由表达最高水平 AVE 标记的细胞引领的，这突出表明 AVE 域内的不对称性决定了其迁移的方向。这些引领细胞的消融会阻止 AVE 的迁移，这表明这些细胞对于正确建立 AP 轴很重要。
