Storey K G, Selleck M A, Stern C D
Developmental Biology Center, University of California at Irvine 92717, USA.
Development. 1995 Feb;121(2):417-28. doi: 10.1242/dev.121.2.417.
Cell lineage analysis has revealed that the amniote organizer, Hensen's node, is subdivided into distinct regions, each containing a characteristic subpopulation of cells with defined fates. Here, we address the question of whether the inducing and regionalising ability of Hensen's node is associated with a specific subpopulation. Quail explants from Hensen's node are grafted into an extraembryonic site in a host chick embryo allowing host- and donor-derived cells to be distinguished. Cell-type- and region-specific markers are used to assess the fates of the mesodermal and neural cells that develop. We find that neural inducing ability is localised in the epiblast layer and the mesendoderm (deep portion) of the medial sector of the node. The deep portion of the posterolateral part of the node does not have neural inducing ability. Neural induction also correlates with the presence of particular prospective cell types in our grafts: chordamesoderm (notochord/head process), definitive (gut) endoderm or neural tissue. However, only grafts that include the epiblast layer of the node induce neural tissue expressing a complete range of anteroposterior characteristics, although prospective prechordal plate cells may also play a role in specification of the forebrain.
细胞谱系分析表明，羊膜动物组织者即亨氏结可细分为不同区域，每个区域都含有具有特定命运的特征性细胞亚群。在此，我们探讨亨氏结的诱导和区域化能力是否与特定亚群相关这一问题。将来自亨氏结的鹌鹑外植体移植到宿主鸡胚的胚外部位，以便区分宿主来源和供体来源的细胞。使用细胞类型和区域特异性标记物来评估发育中的中胚层和神经细胞的命运。我们发现，神经诱导能力定位于结内侧区域的上胚层和中内胚层（深部）。结后外侧部分的深部没有神经诱导能力。神经诱导还与我们移植体中特定预期细胞类型的存在相关：脊索中胚层（脊索/头部突起）、定形（肠道）内胚层或神经组织。然而，只有包含结上胚层的移植体才能诱导表达完整前后特征范围的神经组织，尽管预期的前索板细胞可能在 forebrain 的特化中也起作用。 （注：原文中“forebrain”直接保留英文，因为在医学专业领域，有些特定术语可能直接用英文更准确，这里可根据实际情况进一步确认其准确的中文表述，比如“前脑” ）
