The Role of MicroRNAs in Axon Pathfinding

MicroRNA 在轴突寻路中的作用

• 批准号: 9805576
• 负责人: Guofa Liu
• 金额: $ 7.48万
• 依托单位: UNIVERSITY OF TOLEDO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-16 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9805576
• 关键词: 3' Untranslated Regions; Axon; Binding; Brain; Chickens; Complex; Cues; Defect; Development; Down-Regulation; Ensure; Floor; Gene Expression; Genetic Transcription; Growth Cones; In Vitro; Mediating; Messenger RNA; MicroRNAs; Molecular; Mus; NTN1 gene; Nervous system structure; Neurodevelopmental Disorder; Neurons; Nucleotides; Pattern; Proteins; RNA; Regulation; Repression; Role; SHH gene; Semaphorins; Signal Pathway; Signal Transduction; Spinal; Spinal Cord; Study models; Translational Repression; Translations; Untranslated RNA; Vertebrates; axon guidance; axonal guidance; axonal pathfinding; base; design; developmental disease; differential expression; experimental study; in vivo; loss of function; mRNA Transcript Degradation; nervous system disorder; neuron development; neuronal circuitry; novel; premature; prevent; protein expression; receptor; receptor expression; response; spatiotemporal

Project Summary In the developing nervous system, proper axon outgrowth and pathfinding are regulated by multiple guidance molecules, their receptors and intracellular signaling pathways. Spatiotemporal regulation of guidance receptor expression facilitates differential responses of neurons to guidance cues in order to form accurate neuronal wiring. In vertebrates, levels of the guidance receptor Robo1 are low in precrossing and high in postcrossing commissural axons (CAs), a pattern functioning as a ‘molecular switch’ to regulate sensitivity to Slit repulsion and guide CA midline crossing. However, the mechanism underlying the fine- tuned spatiotemporal regulation of Robo1 expression remains largely unknown. MicroRNAs (miRNAs) regulate gene expression by binding specifically to the 3’untranslated region (3’UTR) of target mRNAs, thus repressing translation and/or inducing mRNA degradation. Our preliminary studies indicate that the Robo1 3’UTR is required for regulation of protein expression in the developing spinal cord. Gga-miR-92, a highly conserved miRNA, is differentially expressed in the developing chicken spinal cord, and regulates Slit sensitivity via suppression of cRobo1 expression in commissural neurons, thereby controlling CA projection and midline crossing. The mature gga-miR-92 has the same sequence as mmu-miR-92a and mmu-miR-92b except the tenth base at the 5’ end of mmu-miR-92b. Mmu-miR-92b can also repress mRobo1 expression by targeting its 3’UTR. Therefore, we hypothesize that mmu-miR-92a and mmu-miR-92b, like gga-miR-92, specifically regulate mRobo1 expression in commissural neurons to control Slit/Robo1-mediated CA guidance in the developing mouse spinal cord. We will examine the role of mmu-miR-92a and mmu-miR- 92b in (1) suppressing mRobo1 expression in developing commissural neurons (Aim 1) and (2) Slit/mRobo1-mediated spinal CA guidance (Aim 2). Studies in this proposal will advance our understanding of molecular mechanisms underlying Slit/Robo-mediated axon guidance.

项目摘要 在发育中的神经系统中，适当的轴突生长和寻路受到多种神经元的调控。 引导分子、其受体和细胞内信号传导途径。时空调控 引导受体的表达促进神经元对引导线索的不同反应， 精确的神经连接在脊椎动物中，引导受体Robo 1的水平在预交叉中较低， 交叉后连合轴突（CA）含量高，这种模式充当调节的“分子开关” 对狭缝排斥和引导CA中线交叉的敏感性。然而，罚款的机制- Robo 1表达的时空调节仍然是未知的。微小RNA（miRNA） 通过特异性结合靶mRNA的3 '非翻译区（3' UTR）来调节基因表达， 抑制翻译和/或诱导mRNA降解。我们的初步研究表明， 3 'UTR是调节发育中的脊髓中的蛋白质表达所必需的。Gga-miR-92，一种高度 保守的miRNA，在发育中的鸡脊髓中差异表达，并调节Slit 通过抑制连合神经元中的cRobo 1表达，从而控制CA投射， 和中线交叉。成熟gga-miR-92与mmu-miR-92 a和mmu-miR-92 b具有相同的序列 除了mmu-miR-92 b的5'端的第10个碱基。Mmu-miR-92 b也可抑制mRobo 1表达 它的3 'UTR。因此，我们假设mmu-miR-92 a和mmu-miR-92 b与gga-miR-92一样， 特异性调节连合神经元中mRobo 1表达以控制Slit/Robo 1介导的CA 指导小鼠脊髓发育。我们将研究mmu-miR-92 a和mmu-miR-92 a在肿瘤细胞中的作用。 92 b在（1）抑制发育中的连合神经元中的mRobo 1表达（目的1）和（2）中的作用 Slit/mRobo 1介导的脊柱CA引导（目的2）。对这一建议的研究将促进我们的理解 Slit/Robo介导的轴突引导的分子机制。