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引导线索的大同源家族的功能分化促进的。因此，我们需要确定使这种功能分化发生的细胞内机制。我们假设，在脊椎动物大脑进化的关键节点出现的任何此类机制都可能在脊椎动物的特定功能中发挥非常重要的作用。本提案的目的是表征生长相关蛋白GAP-43在体内神经发生和轴突引导过程中的功能。GAP-43在硬骨鱼进化过程中首次出现，这是一个关键时刻，连续移动的连接首次被用作一种发育机制。它在神经元功能的各个方面起着重要作用。在轴突细胞粘附分子（CAM）介导的信号转导中，GAP-43是必需的，并且在脊椎动物神经元的成熟中显然是必需的：GAP-43（-/-）小鼠的围产期死亡与轴突寻路的严重异常有关，这种异常会影响皮层的图谱形成。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，GAP-43位点的缺失也会引起常染色体显性综合征，包括ACC。这一点，再加上GAP-43在cam介导的信号传导中的重要作用，使得澄清GAP-43（-/-）和（+/-）小鼠中所见的缺陷变得至关重要。在本研究中，我们将结合体内和体外的神经解剖学和免疫组织化学方法，以确定在皮层前驱神经元的神经发生和轴突生长过程中，GAP-43的表达失败如何反过来影响丘脑传入事件在其成长为新皮层时的组织，从而建立功能图谱。接下来，我们将确定（+/-）ACC小鼠皮层输出神经轴突生长缺陷是否反映了先锋轴突识别胼胝体引导信号的失败，以及（+/-）表型的单倍不足和外显性是如何被调节的。最后，我们将利用一种基因工程小鼠在体内直接检测嗅皮层的图谱形成。该结果将解决中枢神经系统神经元发育过程中GAP-43功能的程度，鉴于其单倍体功能不全，也可能对人类神经系统疾病产生影响。3 erformance网站(S)(组织、城市、国家)药理学系纽约州立大学健康科学中心750年e·亚当斯圣锡拉丘兹,纽约13210关键人员 ======================================== 节结束 ===========================================

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===========================================