Regulation of Axon Guidance by Second Messengers

描述（来自申请人摘要的逐字）： 这项研究是为了更好地了解信号转导级联， 细胞骨架重排是引导轴突延伸所必需的， vivo.将生长锥引导至它们的目标需要特定的和 多种细胞外配体与受体之间的相互作用 生长锥的表面。虽然大家族的扩散，细胞表面和 细胞外基质（ECM）结合的配体及其受体已经被 虽然已经鉴定了这些细胞，但对细胞内信号传导系统的了解相对较少。 以及受体-配体相互作用下游的细胞骨架重排。 在发育中的胚胎中尤其如此，生长锥必须 通过与以下各项的动态组合的相互作用而生成的积分信号 神经系统中的分子梯度、路标和边界。 细胞内钙和cAMP是两个关键的第二信使系统， 被证明可以调节轴突的生长和引导。肌动蛋白丝和 微管是两个关键的细胞骨架元素， 生长锥运动和细胞外信号的检测。本研究提出 研究钙瞬变、cAMP信号传导和细胞骨架的作用， 在发育中的非洲爪蟾脊髓内特定选择点的重排 脊髓和/或在体外使用特定的 荧光探针、笼状化合物、药理学试剂和分子 扰动具体而言，我们建议：1）确定钙的作用 运动神经元（MN）和连合神经元的发散性选择的瞬变 中间神经元（CI）生长锥在腹侧神经束选择点， 脊髓2)检测cAMP依赖性蛋白激酶信号传导的功能 引导线人穿过地板3)评估地方和 生长锥在基质边界处转动的全局钙瞬变， 体外4)描述自发和强加钙的影响 生长锥细胞骨架动力学的瞬变。这些研究将提供新的 关于第二信使的作用的信息 生长锥在体内选择点。这是重要而必要的一步 在我们对生长锥定位机制的理解中， 在发育中的胚胎的复杂环境中的靶点。另外这款 研究将确定如何短暂的全球和局部海拔第二 信使调节细胞骨架的动态组装和拆卸 控制生长锥运动的成分。

DESCRIPTION (Verbatim from the Applicant's Abstract): The long range goal of this research is to better understand the signal transduction cascades and cytoskeletal rearrangements that are necessary for guided axon extension in vivo. Guidance of growth cones to their targets requires specific and interactions between multiple extracellular ligands with receptors on the surface of growth cones. While large families of diffusible, cell surface and extracellular matrix (ECM) bound ligands and their receptors have been identified, relatively little is known of the intracellular signaling systems and cytoskeletal rearrangements downstream of receptor-ligand interactions. This is especially true within the developing embryo, where growth cones must integrate signals generated by interactions with dynamic combinations of molecular gradients, guideposts and boundaries in the nervous system. Intracellular calcium and cAMP are two key second messenger systems that have been shown to regulate axon growth and guidance. Actin filaments and microtubules are two key cytoskeletal elements that are required for proper growth cone motility and detection of extracellular cues. This study proposes to investigate the role of calcium transients, cAMP signaling and cytoskeletal rearrangements at specific choice points within the developing Xenopus spinal cord and/or at artificial choice points created in vitro using specific fluorescent probes, caged-compounds, pharmacological agents and molecular perturbations. Specifically, we propose to: 1)Determine the role of calcium transients in the divergent choice made by motoneuron (MN) and commissural interneuron (CI) growth cones at the ventral fascicle choice point in the spinal cord. 2) Examine the function of cAMP-dependent protein kinase signaling in the guidance of CI's through the floorplate. 3)Assess the role of local and global calcium transients in growth cone turning at a substrate boundary in vitro. 4)Characterize the effects of spontaneous and imposed calcium transients on growth cone cytoskeletal dynamics. These studies will provide new information about the role of second messenger changes in the guidance of growth cones at choice points in vivo. This is an important and necessary step in our understanding of the mechanisms by which growth cones locate their targets in the complex environment of a developing embryo. In addition, this study will identify how transient global and local elevations of second messengers regulate the dynamic assembly and disassembly of cytoskeletal components that control growth cone motility.