Storey K G, Goriely A, Sargent C M, Brown J M, Burns H D, Abud H M, Heath J K
Department of Human Anatomy, University of Oxford, UK.
Development. 1998 Feb;125(3):473-84. doi: 10.1242/dev.125.3.473.
Signals that induce neural cell fate in amniote embryos emanate from a unique cell population found at the anterior end of the primitive streak. Cells in this region express a number of fibroblast growth factors (FGFs), a group of secreted proteins implicated in the induction and patterning of neural tissue in the amphibian embryo. Here we exploit the large size and accessibility of the early chick embryo to analyse the function of FGF signalling specifically during neural induction. Our results demonstrate that extraembryonic epiblast cells previously shown to be responsive to endogenous neural-inducing signals express early posterior neural genes in response to local, physiological levels of FGF signal. This neural tissue does not express anterior neural markers or undergo neuronal differentiation and forms in the absence of axial mesoderm. Prospective mesodermal tissue is, however, induced and we present evidence for both the direct and indirect action of FGFs on prospective posterior neural tissue. These findings suggest that FGF signalling underlies a specific aspect of neural induction, the initiation of the programme that leads to the generation of the posterior central nervous system.
在羊膜动物胚胎中诱导神经细胞命运的信号源自原条前端发现的独特细胞群。该区域的细胞表达多种成纤维细胞生长因子（FGFs），这是一组分泌蛋白，与两栖动物胚胎神经组织的诱导和模式形成有关。在这里，我们利用早期鸡胚的大尺寸和易操作性，专门分析FGF信号在神经诱导过程中的功能。我们的结果表明，先前显示对内源性神经诱导信号有反应的胚外外胚层细胞，在局部生理水平的FGF信号作用下，表达早期后部神经基因。这种神经组织不表达前部神经标记物，也不进行神经元分化，并且在没有轴向中胚层的情况下形成。然而，预期的中胚层组织被诱导，并且我们提供了FGFs对预期后部神经组织直接和间接作用的证据。这些发现表明，FGF信号是神经诱导特定方面的基础，即导致后中枢神经系统产生的程序的启动。
