Regulation of cortical circuit formation by subcellular compartmentalization of mRNA translation

项目摘要/摘要 大脑皮层和其他投射神经元的轴突投射比胞体长103-105倍 直径精度极高。生长锥体(GC)是解释轴突的特殊亚细胞隔室 引导和目标派生的信号，并执行特定亚型的计划，以确保适当的电路和突触 队形。因为GC从细胞体延伸到很远，需要几个小时到几天的时间才能通过轴突将分子送到它们那里 在交通方面，地方政府必须是“半自治”的。已提出将本地翻译作为本地控制的一种机制 生长锥功能，但体内局部翻译的mRNAs的类型和多样性在很大程度上是未知的。更广泛地说， 神经元中的翻译调节可能是正确建立和维持长距离 电路。多发性神经发育(例如：脆性X综合征)和神经退行性疾病(例如：ALS/FTD)是 由RNA结合蛋白的突变引起的，这种突变直接或间接地扰乱了RNA加工的几个方面， 并最终导致翻译输出的改变。我的项目解决了转换性法规如何有助于 利用我们新开发的低输入核糖体进行亚型识别和皮质回路形成 分析方法：1)比较翻译输出并识别体细胞中差异翻译的mRNAs 多个特定皮质投射神经元亚型之间的关系；2)分析胼胝体局部平移的全景 投影神经元(CPN)GC以确定在GC中特定本地翻译的候选调节器；3) 从功能上研究新奇的，选择局部GC翻译的候选者在膝盖骨投射神经元回路的形成。 该项目对翻译中的两个亚型差异进行了相对全面的活体调查，以及 地方性翻译及其在地方政府中的机制。生成的数据和探索的概念将提供深入而严谨的 了解翻译调控多样性和神经亚型之间的区别的基础，以及 在电路开发过程中在GC中本地翻译的mRNAs的类别。除了严格调查独一无二的 远端神经元亚细胞中回路形成、RNA运输和翻译调控的交叉点生物学 车厢，它也有很大的

Project Summary/Abstract Cerebral cortex and other projection neurons extend axonal projections 103-105 times longer than their cell body diameters with exquisite precision. Growth cones (GCs) are specialized subcellular compartments that interpret axon guidance and target-derived signals, and carry out subtype-specific programs to ensure appropriate circuit and synapse formation. Because GCs extend so far from cell bodies that it takes hours to days to send molecules to them via axonal transport, GCs must be “semi-autonomous”. Local translation has been proposed as a mechanism for local control of growth cone function, but the types and diversity of locally translated mRNAs in vivo is largely unknown. More broadly, translational regulation in neurons is likely a crucial mechanism for properly establishing and maintaining long-range circuitry. Multiple neurodevelopmental (ex: Fragile X-Syndrome), and neurodegenerative (ex: ALS/FTD) diseases are caused by mutations in RNA binding proteins that both directly and indirectly disrupt several aspects of RNA processing, and culminate in altered translational output. My project addresses how translational regulation contributes to the development of subtype identity and cortical circuit formation by employing our newly-developed, low-input ribosome profiling approach to: 1) compare translational outputs and identify mRNAs in the somata that are differentially translated between multiple specific cortical projection neuron subtypes; 2) analyze the full landscape of local translation in callosal projection neuron (CPN) GCs to identify candidate regulators that are specifically locally translated in GCs; 3) functionally investigate novel, select locally GC-translated candidates in callosal projection neuron circuit formation. This project undertakes a relatively comprehensive, in vivo investigation of both subtype differences in translation, and local translation and its mechanisms in GCs. The data generated and concepts explored will provide a deep and rigorous foundation for understanding translational regulatory diversity and distinctions between neural subtypes, and the categories of mRNAs locally translated in GCs during circuit development. Beyond rigorously investigating the unique biology at the intersection of circuit formation, RNA trafficking, and translational regulation in distal neuronal subcellular compartments, it also has substantial