REGULATION OF THE NEURAL DETERMINATION GENE MASH1

神经元的发育和存活依赖于一个复杂的网络 细胞之间的相互作用。每一个的区别 神经系统中的数百种细胞类型都是由 一组特定的基因对多种细胞外和 细胞内信号已知的少数神经元决定基因之一 在哺乳动物神经系统中， MASH 1. MASH 1在早期前体细胞亚群中瞬时表达， 中枢和外周神经系统中的细胞，是必不可少的 在特定神经元的发育过程中。转基因小鼠缺乏 正常基因是交感神经，副交感神经， 肠和嗅觉神经系统。为了了解分子 神经元发育的机制，我们必须了解是什么调节了神经元的发育。 这个基因的表达。本研究的第一个目标是 鉴定调控转录的顺式作用元件， MASH 1. 这将通过分析DNA的能力来实现 MASH 1基因的蛋白质编码区的5'和3'序列， 指导报告基因在空间和时间上的表达， 模式与细胞培养物中MASH 1表达的模式相同， 转基因小鼠由于视黄酸可以诱导MASH 1的表达， 响应于该诱导物的顺式作用调节元件也将 定义了一旦MASH 1基因座中的调控元件被激活， 描绘，它们将被用作探针，以确定蛋白质， 结合它们并调节MASH 1表达模式。我们将 最后筛选cDNA表达文库，鉴定编码 这些DNA结合蛋白。通过定义介导 神经特化的最早阶段，这些蛋白质的鉴定 将提供一个更好的了解分子机制的重要 在哺乳动物神经系统的发育过程中。

The development and survival of neurons depends upon an intricate network of interactions between cells. The differentiation of each of the hundreds of cell types in the nervous system results from the expression of a specific set of genes in response to multiple extracellular and intracellular signals. One of the few neuronal determination genes known in the mammalian nervous system is that encoding the transcription factor MASH 1. MASH 1 is expressed transiently in subsets of early precursor cells in both the central and peripheral nervous systems and is essential in the development of particular neurons. Transgenic mice lacking the normal gene are missing neurons in the sympathetic, parasympathetic, enteric, and olfactory nervous systems. To understand the molecular mechanism of neuronal development, we must learn what regulates the expression of this gene. The first goal of the research proposed here is to identify the cis-acting elements that regulate the transcription of MASH1. This will be accomplished by assaying the ability of DNA sequences 5' and 3' to the protein-coding region of the MASH 1 gene to direct the expression of a reporter gene in a spatial and temporal pattern identical to that for MASH 1 expression in cell culture and transgenic mice. Because retinoic acid can induce MASH 1 expression, the cis-acting regulatory elements responsive to this inducer will also be defined. Once the regulatory elements in the MASH 1 locus have been delineated, they will be used as probes to identify the proteins that bind them and that regulate the pattern of MASH 1 expression. We shall finally screen cDNA expression libraries to identify the genes encoding such DNA-binding proteins. By defining the factors that mediate the earliest stages of neural specification, identification of these proteins will provide a better understanding of the molecular mechanisms important in development of the mammalian nervous system.