New approaches to local translation: spaceSTAMP of proteins synthesized in axons

描述（由申请人提供）：多年来，传统观点认为在哺乳动物神经元的轴突中不发生蛋白质翻译。相反，轴突功能所需的所有蛋白质都应该在细胞体中合成，然后运送到轴突。最近，越来越多的数据提供了证据，证明在哺乳动物神经系统的轴突中发现了许多mrna。有证据表明，轴突的局部翻译可能受到电活动、神经营养因子和应激的调节，这导致了轴突翻译对学习期间的可塑性或对环境应激源的反应特别重要的假设。为了支持这一观点，局部翻译缺陷与脆性X综合征（脆性X综合征会导致认知问题和自闭症行为）和副肿瘤疾病（副肿瘤疾病会导致一些肺癌患者患上脑炎）有关。然而，调控局部翻译的机制以及局部翻译缺陷导致神经精神功能障碍的原因尚不清楚。在某种程度上，这反映了当前分析局部蛋白质合成或识别依赖于受调节的局部翻译的生物功能的方法的不足。为了解决这个问题，我们开始与Michael Lin合作。Michael最近开发了一种名为timeSTAMP的技术，用于识别在特定时间段翻译的蛋白质(4)。我们正在与Michael合作修改这种方法，使其可以用于spaceSTAMP，标记在特定位置翻译的蛋白质，并随时间和空间跟踪它们。本提案的目标是开发spaceSTAMP方法并使用它来询问：轴突中是否存在受调节的局部翻译？这些局部翻译的蛋白质在功能上重要吗？局部翻译蛋白是否局限于轴突腔室，或者它们是否促进轴突终末与神经元细胞体的远程部分之间的通信？这些研究将开发和测试一种spaceSTAMP技术，该技术允许人们标记轴突合成的蛋白质，并在时间和空间上跟踪这些成分。这种方法可以被科学界用来解决诸如脆性X基因产物的功能重要性，以及活动或神经营养因子调节翻译导致神经精神疾病的方式等问题。

DESCRIPTION (provided by applicant): For many years, conventional wisdom declared that no protein translation occurs in the axons of mammalian neurons. Instead all proteins needed for axonal functions were supposed to be synthesized in the cell bodies and shipped out to the axons. More recently, accumulating data has provided evidence that many mRNAs are found in axons in the mammalian nervous system. Evidence indicating that local translation in axons may be regulated by electrical activity, neurotrophic factors, and stress, have led to the hypothesis that axonal translation is particularly important for plasticity during learning, or in response to environmental stressors. In support of this idea, defects in local translation have been linked to Fragile X syndrome, which causes cognitive problems and autistic behaviors, and paraneoplastic disorders, which cause encephalitis in some patients with lung cancers. However, the mechanisms regulating local translation, and why defects in local translation lead to neuro-psychiatric dysfunction, are not understood. In part, this reflects the inadequacy of current approaches for analyzing local protein synthesis or identifying biological functions that rely on regulated local translation. To address this problem we initiated a collaboration with Michael Lin. Michael recently developed a technique called timeSTAMP, to identify proteins that are translated at a particular time period (4). We are working with Michael to modify this approach so it can be used for spaceSTAMP, to tag proteins translated in a particular location, and follow them over time and space. The goal of this proposal is develop the spaceSTAMP approach and use it to ask: Is there regulated local translation in axons? Are such locally translated proteins functionally important? Are locally translated proteins restricted to the axonal compartment, or do they facilitate communication between axonal terminals and remote portions of the neuronal cell body? These studies will develop and test a spaceSTAMP technique that allows one to tag proteins synthesized in axons, and to follow these components in time and space. This approach can then be used by the scientific community to solve problems such as the functional importance of the fragile X gene product, and ways in which activity or neurotrophin regulated translation contribute to neuro-psychiatric disorders. PUBLIC HEALTH RELEVANCE: These studies will develop a new technique that we call spaceSTAMP. This technique allows one to tag proteins made in one part of the cell and to follow these components as they move in time and space. This approach will enable the scientific community to understand diseases that affect local protein synthesis; these diseases include Fragile X syndrome, one of the most common inherited causes of developmental delay and of autism.