DYNAMIN AND NEURONAL MORPHOGENESIS

动力和神经元形态发生

• 批准号: 2271372
• 负责人: RAUL A. URRUTIA
• 金额: $ 9.95万
• 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/2271372
• 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常功能取决于特定的 布线模式由开发程序确定。 这个节目 指导神经元如何在早期分裂，迁移到最终阶段 目的地，超出细胞过程，最后，建立突触 其他神经元或不同的靶细胞。 相当数量的人类 疾病的发生是由于异常完成此过程的结果 发展计划。 其中许多疾病，包括唐氏病 综合症，几种形式的先天性智力低下， 苯丙酮尿症、营养不良和精神分裂症的特点是 神经元的正常结构和数量发生改变 神经突。 微管和微管相关蛋白和酶 已知在正常布线的发展中发挥着至关重要的作用 神经系统中的模式通过参与延伸 神经元过程。 我们的实验室专注于特定的角色 微管相关酶，动力，在神经元的延伸中 流程。 Dynamin 是一种微管激活的 GTP 酶，可结合并 在体外以核苷酸依赖性方式交联微管， 因此，有人建议将其用作体内基于微管的马达。 我们进行了重要的初步观察，表明：1) 动力对于神经突形成至关重要，2) 动力是局部的 在神经元生长锥处。 此外，我们还克隆了一种新型动力 编码在大鼠脑中表达的第二种亚型的基因。 从这些 研究中，我们假设动力有助于形成 神经突在发育过程中通过以下方式：a）维持神经突的正常结构 通过交联和定位微管的神经元过程 神经突和 b) 参与蛋白质的内吞再循环 这对于神经突的生长很重要。 我们设计了实验 将动力水平与两个神经突的形成相关联 海马神经元和 PC12 细胞在体外发育。 此外， 其他研究旨在改变动力蛋白的表达 反义技术并确定其水平是否降低 蛋白质会损害神经突的生长。 我们将使用最先进的视频 电子显微镜与分子生物学相结合 确定微管网络完整性的技术和 动力减去神经元中的内吞囊泡运输途径。 到 据我们所知，这是第一项深入了解 动力蛋白在神经元发育中的体外作用。 我们很乐观 神经突相关机制的详细表征 形成将帮助我们更好地了解许多精神疾病。