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

描述(申请人提供)：多年来，传统智慧宣称，哺乳动物神经元的轴突中不存在蛋白质翻译。相反，轴突功能所需的所有蛋白质都应该在细胞体中合成并运送到轴突。最近，积累的数据提供了证据，表明在哺乳动物神经系统的轴突中发现了许多mRNAs。有证据表明轴突的局部翻译可能受电活动、神经营养因子和应激的调节，这导致了一种假说，即轴突翻译对学习过程中的可塑性或对环境应激的反应特别重要。支持这一观点的是，局部翻译缺陷与脆性X综合征和副肿瘤障碍有关，脆性X综合征会导致认知问题和自闭症行为，副肿瘤障碍会导致一些肺癌患者发生脑炎。然而，调节局部翻译的机制，以及局部翻译的缺陷为什么会导致神经精神功能障碍，目前还不清楚。在一定程度上，这反映了目前分析局部蛋白质合成或识别依赖于受调控的局部翻译的生物功能的方法的不足。为了解决这个问题，我们发起了与Michael Lin的合作。迈克尔最近开发了一种名为时间戳的技术，以识别在特定时间段翻译的蛋白质。我们正在与Michael合作修改这种方法，以便它可以用于spaceSTAMP，标记在特定位置翻译的蛋白质，并在时间和空间上跟踪它们。这项提议的目标是发展spaceSTAMP方法，并用它来问：轴突中是否存在受监管的局部翻译？这种局部翻译的蛋白质在功能上很重要吗？局部翻译的蛋白质是否仅限于轴突室，或者它们是否促进轴突终末和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，允许人们标记轴突中合成的蛋白质，并在时间和空间上跟踪这些成分。然后，科学界可以使用这种方法来解决一些问题，例如脆性X基因产物的功能重要性，以及活动或神经营养素调节的翻译导致神经精神障碍的方式。 与公共健康相关：这些研究将开发一种我们称为spaceSTAMP的新技术。这项技术允许人们标记细胞某一部分产生的蛋白质，并随着这些成分在时间和空间上的移动而跟踪它们。这种方法将使科学界能够了解影响当地蛋白质合成的疾病；这些疾病包括脆性X综合征，这是导致发育迟缓和自闭症的最常见遗传原因之一。

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.