Molecular Mechanisms of Cellular Differentiation in the Nervous System

描述（由申请人提供）：本提案的主要目标是了解发育中的神经系统中神经元和胶质细胞分化的分子基础。在这里，控制顺序运动神经元和少突胶质细胞分化的机制，从一个单一的前体结构域（pMN）在脊髓内将进行调查。GDE 2是一种含有细胞外甘油磷酸二酯磷酸二酯酶（GDPD）结构域的六跨膜（6-TM）蛋白，它是通过GDPD活性诱导运动神经元分化所必需和充分的。在这个提议中，生物化学和体内方法将被用来定义GDE 2 GDPD活性的机制，并确定6- TM GDPD酶功能的潜在生理底物。引人注目的是，第二个6-TM GDE蛋白显示与GDE 2互补的表达，这与少突胶质细胞的产生一致。将采用体内和体外方法来测试该第二GDPD调节系统在少突胶质细胞特化、分化和成熟中的功能。GDE 2基因的去除导致胶质细胞生成期少突胶质细胞数量的增加，表明GDE 2可能阻止少突胶质细胞分化的过早启动。这一假设将得到检验 使用生物化学、遗传学和功能方法的组合。总之，这些研究将提供新的GDPD依赖性调控系统，控制运动神经元和少突胶质细胞分化的机制的见解，并确定它们是否交叉调节脊髓神经发生和胶质细胞发生的时间控制。

DESCRIPTION (provided by applicant): The major goals of this proposal are to understand the molecular basis of neuronal and glial differentiation in the developing nervous system. Here, the mechanisms that control sequential motor neuron and oligodendrocyte differentiation from a single progenitor domain (pMN) within the spinal cord will be investigated. GDE2, a six-transmembrane (6-TM) protein that contains an extracellular glycerophosphodiester phosphodiesterase (GDPD) domain is necessary and sufficient to induce motor neuron differentiation through GDPD activity. In this proposal, biochemical and in vivo approaches will be used to define the mechanism of GDE2 GDPD activity and identify potential physiological substrates of 6- TM GDPD enzymatic function. Strikingly, a second 6-TM GDE protein shows complementary expression to GDE2 that is coincident with oligodendrocyte generation. In vivo and in vitro approaches will be taken to test the function of this second GDPD regulatory system in oligodendrocyte specification, differentiation and maturation. Genetic ablation of GDE2 results in increased numbers of oligodendrocytes in the gliogenic period, suggesting that GDE2 might prevent the premature initiation of oligodendrocyte differentiation. This hypothesis will be tested using a combination of biochemical, genetic and functional approaches. Taken together, these studies will provide mechanistic insight into novel GDPD-dependent regulatory systems that control motor neuron and oligodendrocyte differentiation, and determine if they intersect to regulate the temporal control of neurogenesis and gliogenesis in the spinal cord.