CONTROL OF FLOOR PLATE INDUCTION BY AXIAL MESODERM

本提案中将描述的实验的目标是 阐明细胞和分子事件潜在的诱导 脊索处的地板。地板是一套专门的 位于胚胎腹中线的神经上皮细胞 脊髓。楼板似乎是造成 腹侧脊髓内神经元的分化和组织 而且，在发展的后期阶段，它在指导中发挥着关键作用 脊髓内的轴突。我们之前已经表明， 特异性的功能和抗原性的区别 底板依赖于来自底层的感应信号 弦乐。这里描述的实验使用一种简单的测试系统来 检测底板特异性基因在人卵巢癌细胞中的诱导表达 通常不会形成底板的外侧神经板。 这个测试将被用来检测发育表达模式和 脊索信号的生化特性及其作为检测手段 方法对活动进行鉴定。我们将使用一个表达式 克隆方法鉴定底板诱导基因的编码序列 活动。从长远来看，目标是通过以下方式了解这些机制 哪些神经上皮细胞对脊索信号作出反应并启动 楼板判别程序。 脊索衍生楼板诱发信号的识别和 对其作用机制的阐明将是 对早期归纳过程的理解及其在分化中的作用 以及早期神经管的组织。

The goal of the experiments to be described in this proposal is to elucidate the cellular and molecular events underlying the induction of the floor plate by the notochord. The floor plate is a specialized set of neuroepithelial cells located at the ventral midline of the embryonic spinal cord. The floor plate appears to be responsible for the differentiation and organization of neurons within the ventral spinal cord and, at later stages of development, plays a pivotal role in the guidance of axons within the spinal cord. We have previously shown that the differentiation of functional and antigenic properties that are specific to the floor plate is dependent on an inductive signal from the underlying notochord. The experiments described here use a simple assay system to measure the induction of floor plate-specific gene expression in cells of the lateral neural plate that would not normally give rise to floor plate. This assay will be used to examine the developmental expression pattern and biochemical properties of the notochord-derived signal and as a detection method in the identification of the activity. We will use an expression cloning approach to identify cDNAs that encode the floor plate-inducing activity. In the longer term, the goal is to understand the mechanisms by which neuroepithelial cells respond to the notochordal signal and initiate a program of floor plate differentiation. The identification of a notochord-derived floor plate-inducing signal and the elucidation of its mechanisms of action will be an important step in the understanding of early inductive processes and in the differentiation and organization of the early neural tube.