DYNAMIN AND NEURONAL MORPHOGENESIS

动力和神经元形态发生

• 批准号: 2271373
• 负责人: RAUL A. URRUTIA
• 金额: $ 9.92万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 1999-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2271373
• 关键词: axon; cell differentiation; crosslink; dendrites; developmental neurobiology; electron microscopy; embryo /fetus tissue /cell culture; endocytosis; guanosinetriphosphatases; isozymes; laboratory rat; microtubule associated protein; microtubules; neurogenesis; video microscopy

Proper functioning of the mammalian nervous system depends on a specific wiring pattern determined by a developmental program. This program directs how neurons divide at early stages, migrate to their final destination, outgrow cell processes and, finally, establish synapses with other neurons or a distinct target cell. A significant number of human diseases occur as a result of an aberrant completion of this developmental program. Many of these diseases, including Down's Syndrome, several forms of congenital mental retardation, phenylketonuria, malnutrition and schizophrenia are characterized by neurons with an alteration in the normal structure and number of neurites. Microtubules and microtubule-associated proteins and enzymes are known to play a crucial role in the development of normal wiring patterns in the nervous system by taking part in the extension of neuronal processes. Our laboratory is focused on the role of a specific microtubule-associated enzyme, dynamin, in the extension of neuronal processes. Dynamin is a microtubule-activated GTPase that binds and cross-links microtubules in vitro in a nucleotide-dependent manner and therefore has been proposed to act as a microtubule-based motor in vivo. We have made important preliminary observations which indicate that 1) dynamin is essential for neurite formation and 2) dynamin is localized at the neuronal growth cone. In addition, we have cloned a novel dynamin gene encoding a second isoform expressed in rat brain. From these studies, we hypothesize that dynamin contributes to the formation of neurites during development by: a) maintaining the normal structure of neuronal processes through cross-linking and positioning microtubules in the neurite and b) participating in the endocytic recycling of proteins which are important for neurite outgrowth. We have designed experiments to correlate the level of dynamin with the formation of neurites in both hippocampal neurons and PC12 cells developing in vitro. Furthermore, additional studies are aimed to alter the expression of dynamin using antisense technology and determine whether a reduced level of this protein impairs neurite outgrowth. We will use state-of-the-art video and electron microscopy in combination with molecular biological techniques to determine the integrity of the microtubule network and endocytic vesicular transport pathway in the dynamin minus neurons. To our knowledge, this is the first study which has provided insight into the in vitro role of dynamin in neuronal development. We are optimistic that a detailed characterization of the mechanisms involved in neurite formation will help us better understand many mental diseases.

哺乳动物神经系统的正确功能取决于特定 由开发程序确定的接线模式。 这个程序 指导神经元如何在早期阶段分裂，迁移到最终 目的地，超越单元过程，最后建立突触 其他神经元或独特的靶细胞。 大量人类 疾病是由于异常完成而导致的 发展计划。 这些疾病中有许多，包括唐 综合征，几种形式的先天性智力低下， 苯基酮，营养不良和精神分裂症的特征是 神经元正常结构改变和数量 神经突。 微管和微管相关蛋白和酶 众所周知，在正常接线的发展中起着至关重要的作用 通过参与延伸的神经系统中的模式 神经元过程。 我们的实验室专注于特定的作用 微管相关酶，动力蛋白，在神经元扩展中 过程。 Dynamin是一种结合和的微管激活的GTPase 以核苷酸依赖性方式在体外交联微管， 因此，已提出在体内充当基于微管的电动机。 我们进行了重要的初步观察，表明1） Dynamin对于神经突的形成至关重要，2）Dynamin是局部的 在神经元生长锥处。 此外，我们克隆了一种新颖的动力学 编码在大鼠脑中表达的第二种同工型的基因。 从这些 研究，我们假设动力蛋白有助于形成 发育过程中的神经突来：a）维持正常结构 神经元过程通过交联和定位微管在 神经突和b）参与蛋白质的内吞回收 这对于神经突生长很重要。 我们设计了实验 将动力蛋白水平与两者中神经突的形成相关 海马神经元和PC12细胞在体外发育。 此外， 其他研究旨在使用使用Dynamin的表达 反义技术并确定是否降低了此水平 蛋白质会损害神经突生长。 我们将使用最先进的视频 和电子显微镜结合分子生物学 确定微管网络和的完整性的技术 动力蛋白减去神经元中的内吞囊泡转运途径。 到 我们的知识，这是第一个研究的研究 动力蛋白在神经元发育中的体外作用。 我们乐观 对神经突带的机制的详细表征 形成将有助于我们更好地了解许多精神疾病。