Mechanisms and Functions of MBP mRNA Transport in Oligodendrocytes

描述（由申请人提供）：在中枢神经系统中，少突胶质细胞在髓鞘的许多同心层中包裹和包裹轴突，这是轴突中有效电信号传递所必需的过程。在多发性硬化症和脑瘫等疾病中， 少突胶质细胞不能形成致密的髓鞘，并且缺乏髓鞘碱性蛋白（MBP）的适当远端定位。MBP是少突胶质细胞中表达最高的mRNA，超过10倍。它也是一种特殊的蛋白质，其mRNA必须转运到少突胶质细胞的远端突起才能翻译。然而，MBP mRNA转运的机制和体内功能仍然是难以捉摸的。该项目旨在确定在货物水平上调节MBP mRNA转运是否是髓鞘形成所必需的。为了可视化MBP mRNA运输活的原代少突胶质细胞，现代成像工具，如RNA结合报告蛋白MS2，将开发用于检测和分析MBP mRNA运动。此外，两个独立的质谱方法将被用来识别MBP mRNA颗粒中参与其运输的蛋白质。运输调节因子通常是支架蛋白，它们能够与多种马达蛋白结合。因此，MBP mRNA转运的候选调节剂将通过其与马达蛋白以及siRNA敲低策略相关联的能力来确认。最后，将制作两种不同的小鼠模型以确定MBP mRNA转运是否是体内髓鞘形成所必需的。该项目将阐明马达蛋白如何与mRNA货物相关联，并确定少突胶质细胞成熟和髓鞘形成关键过程的分子机制，并将对神经胶质细胞生物学，分子马达，RNA蛋白生物学和髓鞘疾病等领域产生重要影响。重要的是，由于远端MBP蛋白表达和致密髓鞘形成在髓鞘形成疾病中失败，这些发现可能揭示刺激疾病中髓鞘形成的新治疗靶点。

DESCRIPTION (provided by applicant): In the central nervous system, oligodendrocytes ensheath and wrap axons in many concentric layers of myelin, a process that is essential for efficient electrical signaling in axons. In diseases such as multiple sclerosis and cerebral palsy, oligodendrocytes fail to form compact myelin and proper distal localization of myelin basic protein (MBP) is absent. MBP is the most highly expressed mRNA in oligodendrocytes by over 10-fold. It is also a special protein who's mRNA must be transported to distal processes of oligodendrocytes before it can be translated. The mechanism and in vivo function of MBP mRNA transport, however, has remained elusive. This project aims to determine whether regulation of MBP mRNA transport at the cargo level is necessary for myelination. In order to visualize MBP mRNA transport in living primary oligodendrocytes, modern imaging tools, such as the RNA-binding reporter protein MS2, will be developed for the detection and analysis of MBP mRNA motility. Furthermore, two independent mass spectrometry approaches will be used to identify proteins in the MBP mRNA granule that are involved in its transport. Regulators of transport are often scaffolding proteins that have the ability to bind to multiple motor proteins. Thus, candidate regulators of MBP mRNA transport will be confirmed via their ability to associate with motor proteins as well as with siRNA knockdown strategies. Finally, two different mouse models will be made to determine whether MBP mRNA transport is necessary for myelination in vivo. The proposed project will elucidate how motor proteins associate with mRNA cargos and identify the molecular mechanism underlying a pivotal process in oligodendrocyte maturation and myelination and will have important implications for the fields of glial cell biology, molecular motors, RNA protein biology, and myelin diseases. Importantly, since distal MBP protein expression and compact myelin formation fail in myelinating diseases, these findings may reveal novel therapeutic targets for stimulating myelination in disease.