Notochordal induction of cell wedging in the chick neural plate and its role in neural tube formation.
Notochordal induction of cell wedging in the chick neural plate and its role in neural tube formation.
复制标题
脊索诱导鸡神经板细胞楔入及其在神经管形成中的作用。
DOI：
10.1002/jez.1402500107
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Schoenwolf,GC
中科院分区：
文献类型：
--
作者：
Smith,JL;Schoenwolf,GC
弯曲的鸡神经板的中间铰点（MHP）的细胞紧密地相对于下面的脊索。这些细胞与相邻侧神经上皮区(L)的细胞不同之处在于，MHP细胞短，主要呈楔形排列，而L细胞高，主要呈纺锤形排列，不呈沟壑排列。这些区域的细胞生成时间也不同。这些一致的差异只有在脊索形成并与神经板建立联系后才能检测到；目前尚不清楚它们是由自我分化还是诱导引起的。进行了两个实验来评估假设，MHP特征的发展是由于脊索和上覆神经上皮细胞之间的诱导相互作用。首先，产生无脊索的鸡胚胎，以确定中线神经上皮细胞是否仍具有典型的MHP特征。在没有脊索的情况下，这些特征没有发展。其次，将分离的鹌鹑脊索片段移植到雏鸡寄主L细胞下，以确定脊索是否能够在L细胞中诱导MHP特性。当移植的脊索节段与宿主L细胞发生对抗时，对抗的L细胞通常表现出典型的MHP特征。总的来说，这些结果提供了强有力的证据，证明脊索在MHP特征的形成中起诱导作用。本研究进一步揭示，在没有MHP特征的情况下，弯曲可以发生，形成具有异常形态的神经管。因此，这些特征的形成，特别是细胞楔入，并不是弯曲所必需的，但在神经管正常横截面形态的形成中起着重要作用。
Cells in the median hinge point (MHP) of the bending chick neural plate are tightly apposed to the underlying notochord. These cells differ from those in adjacent lateral neuroepithelial areas (L) in that MHP cells are short and mainly wedge‐shaped and line a furrow, whereas L cells are tall and mainly spindle‐shaped and do not line a furrow. Cell generation time also differs in these regions. These consistent differences are detectable only after the notochord has formed and established contact with the neural plate; it is unclear whether they result from self‐differentiation or induction. Two experiments were performed to evaluate the hypothesis that MHP characteristics develop owing to inductive interactions between the notochord and overlying neuroepithelial cells. First, notochordless chick embryos were generated to determine whether midline neuroepithelial cells still developed typical MHP characteristics. In the absence of the notochord, such characteristics did not develop. Second, isolated segments of quail notochord were transplanted subjacent to L of chick hosts to ascertain whether the notochord is capable of inducing MHP characteristics in L cells. When transplanted notochordal segments established apposition with host L cells, the apposing L cells usually developed typical MHP characteristics. Collectively, these results provide strong evidence that the notochord plays an inductive role in the formation of MHP characteristics. This investigation further revealed that bending can occur in the absence of MHP characteristics, forming a neural tube with an abnormal morphology. Thus, the formation of such characteristics, particularly cell wedging, is not required for bending but plays a major role in generating the normal cross‐sectional morphology of the neural tube.