Placzek M, Jessell T M, Dodd J
Department of Physiology and Cellular Biophysics, Columbia University, New York, New York 10032.
Development. 1993 Jan;117(1):205-18. doi: 10.1242/dev.117.1.205.
The floor plate is located at the ventral midline of the neural tube and has been implicated in neural cell patterning and axon guidance. To address the cellular mechanisms involved in floor plate differentiation, we have used an assay that monitors the expression of floor-plate-specific antigens in neural plate explants cultured in the presence of inducing tissues. Contact-mediated signals from both the notochord and the floor plate act directly on neural plate cells to induce floor plate differentiation. Floor plate induction is initiated medially by a signal from the notochord, but appears to be propagated to more lateral cells by homeogenetic signals that derive from medial floor plate cells. The response of neural plate cells to inductive signals declines with embryonic age, suggesting that the mediolateral extent of the floor plate is limited by a loss of competence of neural cells. The rostral boundary of the floor plate at the midbrain-forebrain junction appears to result from the lack of inducing activity in prechordal mesoderm and the inability of rostral neural plate cells to respond to inductive signals.
底板位于神经管的腹侧中线，与神经细胞模式形成和轴突导向有关。为了研究参与底板分化的细胞机制，我们采用了一种检测方法，该方法可监测在诱导组织存在的情况下培养的神经板外植体中底板特异性抗原的表达。来自脊索和底板的接触介导信号直接作用于神经板细胞，以诱导底板分化。底板诱导由脊索发出的信号在内侧启动，但似乎是由源自内侧底板细胞的同源信号传播到更外侧的细胞。神经板细胞对诱导信号的反应随胚胎年龄而下降，这表明底板的中外侧范围受到神经细胞能力丧失的限制。中脑-前脑交界处底板的头侧边界似乎是由于脊索前中胚层缺乏诱导活性以及头侧神经板细胞无法对诱导信号作出反应所致。
