FUNCTIONS OF GAP-43 BY GENETIC MANIPULATION

超出所提供的空间。 脊椎动物中枢神经系统功能复杂性的进化在很大程度上是由神经发生和指导线索的大同源家族内的功能分歧促进的。因此，我们需要确定使这种功能分歧发生的细胞内机制。我们假设，在脊椎动物大脑进化过程中的关键时刻出现的任何此类机制都可能在脊椎动物特有的功能中发挥非常重要的作用。该提案的目标是表征一种候选蛋白（生长相关蛋白GAP-43）在体内神经发生和轴突引导过程中的功能。GAP-43最早出现在硬骨鱼进化过程中，这是一个关键时刻，当时不断变化的连接首次开始被用作一种发育机制。它在神经元功能的各个方面都起着重要作用。GAP-43是轴突中细胞粘附分子（CAM）介导的信号转导所必需的，并且显然是脊椎动物神经元成熟所必需的：GAP-43（-/-）小鼠围产期死亡与影响皮质中地图形成的轴突寻路严重异常相关。此外，GAP-43（+/-）小鼠表现出常染色体显性综合征，其中一个主要症状是胼胝体（ACC）发育不全。同样，在人类中，差距-43基因座的缺失也会引起包括ACC在内的常染色体显性遗传综合征。这一点，以及GAP-43在CAM介导的信号传导中的重要作用，使得澄清差距-43（-/-）和（+/-）小鼠中观察到的缺陷至关重要。在这个建议中，我们将联合收割机神经解剖学和免疫组织化学方法在体内和体外，以确定如何失败表达GAP-43在神经发生和轴突生长的皮层先锋神经元反过来影响组织丘脑传入，因为他们成长为新皮层建立功能地图。接下来，我们将确定ACC（+/-）小鼠皮层传出神经轴突生长缺陷是否反映了先驱轴突识别胼胝体引导线索的失败，以及（+/-）表型的单倍不足和突变是如何调节的。最后，我们将利用一种基因工程小鼠直接研究嗅觉皮层在体内的地图形成。这些结果将解决GAP-43在CNS神经元发育过程中的功能程度，鉴于其单倍不足，也可能对人类神经系统疾病产生影响。3实验地点（组织、城市、州）纽约州立大学医学科学中心药理学系750，E。亚当斯街锡拉丘兹，纽约13210关键人员=

EXCEED THE SPACE PROVIDED. The evolution of functional complexity in the vertebrate CNS has been facilitated in large part by functional divergence within large homologous families of neurogenesis and guidance cues. We therefore need to identify the intracellular mechanisms that have enabled this functional divergence to occur. We have hypothesized that any such mechanisms arising at crucial junctures during evolution of the vertebrate brain will likely play highly important roles in vertebrate-specific functions. The goal of this proposal is to characterize the functions of one candidate, the growth-associated protein GAP-43, during neurogenesis and axon guidance in vivo. GAP-43 first appeared during teleost evolution ~ a critical juncture when continually shifting connections first began to be used as a developmental mechanism. It plays a major role in all aspects of neuronal function. GAP-43 is required for the transduction of cell-adhesion molecule (CAM) mediated signaling in axons and is clearly required for maturation of vertebrate neurons: GAP-43 (-/-) mice die perinatally in association with severe abnormalities of axonal pathfinding that affects map formation in the cortex. In addition, GAP-43 (+/-) mice display an autosomal dominant syndrome of which one major symptom is agenesis of the corpus callosum (ACC). Likewise in humans, deletions of the GAP-43 locus also give rise to an autosomal dominant syndrome that includes ACC. This, together with the essential role of GAP-43 in CAM-mediated signaling, makes it critical to clarify the deficiencies seen in the GAP-43 (-/-) and (+/-) mice. In this proposal we will combine neuroanatomical and immunohistochemical methods in vivo and in vitro to determine how failure to express GAP-43 during neurogenesis and axon outgrowth of cortical pioneer neurons in turn influences organization of thalamortical afferents as they grow into neocortex to establish functional maps. Next we will determine whether defective axon outgrowth of cortical efferents in (+/-) mice with ACC reflects failure of pioneer axons to recognize callosal guidance cues, as well as how haploinsufficiency and penetrance of the (+/-) phenotype is regulated. Finally we will take advantage of a strain of genetically engineered mice to directly examine map formation in olfactory cortex in vivo. The results will address the extent of GAP-43 function during neuronal development in the CNS that, given its haploinsufficiency, may also have consequences on human neurological disorders. 3ERFORMANCE SITE(S) (organization, city, state) Department of Pharmacology SUNY Health Science Center 750, E. Adams St Syracuse, NY 13210 KEY PERSONNEL ========================================Section End===========================================