SORTING & TRANSPORT OF SPECIFIC NEURONAL GLYCOPROTEINS

排序

• 批准号: 3404193
• 负责人: RICHARD T AMBRON
• 金额: $ 16.15万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3404193
• 关键词: Gastropoda; autoradiography; axon; cell nucleus; developmental neurobiology; gel electrophoresis; glycoproteins; growth cones; high performance liquid chromatography; histochemistry /cytochemistry; motor neurons; nerve /myelin protein; neuromuscular junction; neuronal transport; neurotransmitters; oligosaccharides; saltwater environment; synaptogenesis; tissue /cell culture

During embryonic development neurons extend processes containing growth cones that locate, recognize, and contact the appropriate targets. A synapse forms, motility ceases and a signal is sent to the cell body that elicits the synthesis of proteins to consolidate and then maintain the synaptic ending. Neither the molecules involved in recognition of the target nor the nature of the communicating signal is known. Our goal is to define these two processes at the molecular level and we have preliminary evidence that glycoproteins are involved in both. Molecules that mediate recognition are present on the growth cone. We recently succeeded in isolating growth cones from a single population of Aplysia motorneurons. Analyses revealed a glycopeptide (GPwga) that is associated with a glycoprotein exposed on the surface of the growth cones. GPwga contain one or more oligosaccharide chains that bind to certain types of muscle cells. We hypothesize that these oligosaccharides are involved in target recognition. We intend to characterize the oligosaccharides and determine if they are able to interfere with the formation of neuromuscular junctions between identified motorneurons and their target muscles in vitro. Although almost nothing is known about the way in which axons and terminals communicate with the soma, it is clear that such communication exists since events such as axotomy, denenervation, etc. elicit changes in somatic protein synthesis. We have injected 3H-monosaccharides directly into the axon of the giant neuron R2 and found that five proteins are glycosylated in the axon. Some of these are subsequently transported toward the cell body. Partial characterization of these glycoproteins suggests the presence of single O-linked N-acetylglucosamine, a modification that is found on transcriptional factors in the nucleus. Consequently, we will test the hypothesis that proteins glycosylated in the axon are transported to the nucleus where they act as signals from the periphery. We have shown that axotomy of Aplysia neurons has affects on protein synthesis that are consistant and quantifiable. We will axotomize the R2 axon to see if it alters the glycosylation of the axonal species and will also modify the glycosylated species, by injecting galactosyl transferase and UDP-galactose into the axon, to see if we can interfere with the signal to the cell soma.

在胚胎发育期间，神经元延伸包含生长的过程。 定位、识别和接触适当目标的锥体。 一 突触形成，运动停止，信号被发送到细胞体， 促进蛋白质的合成，以巩固和维持 突触末梢 参与识别的分子 目标也不知道通信信号的性质。 我们的目标是 在分子水平上定义这两个过程， 证据表明糖蛋白参与了这两个过程。 介导识别的分子存在于生长锥上。 我们 最近成功地从一个单一的种群中分离出了生长锥， 运动神经元缺失。 分析表明，糖肽（GPwga）， 与暴露在生长锥表面的糖蛋白相关。 GPwga含有一条或多条寡糖链， 的肌肉细胞。 我们假设这些寡糖与 目标识别。 我们打算表征低聚糖， 确定它们是否能够干扰神经肌肉的形成， 运动神经元和目标肌肉之间的连接 体外 尽管我们对轴突和终末 与索马沟通，很明显，这种沟通存在，因为 诸如轴突切断、去神经支配等事件引起躯体神经系统的变化。 蛋白质合成。 我们已经将3 H-单糖直接注入到 巨大神经元R2的轴突，发现五种蛋白质被糖基化， 在轴突中。 其中一些随后被运送到细胞 身体 这些糖蛋白的部分特征表明， 存在单个O-连接的N-乙酰葡糖胺， 发现于细胞核中的转录因子上。 因此，我们将 测试轴突中糖基化的蛋白质被转运的假设 到细胞核，在那里它们充当来自外围的信号。 我们有 表明，轴突切断的神经元有影响蛋白质的合成， 是一致的和可量化的。 我们将切断R2轴突， 它改变了轴突种类的糖基化， 通过注射半乳糖基转移酶和UDP-半乳糖， 进入轴突，看看我们是否能干扰细胞索马的信号。