Transcriptional mechanisms coordinating midline and motor axon guidance

协调中线和运动轴突引导的转录机制

• 批准号: 8629056
• 负责人: Greg J. Bashaw
• 金额: $ 36.03万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8629056
• 关键词: Address; Alzheimer' s Disease; Axon; Biochemical; Biological Assay; Cell Nucleus; Cell Surface Receptors; Cell surface; Cells; Code; Cues; Defect; Development; Drosophila genus; Ectopic Expression; Embryo; Exhibits; Family; Gene Targeting; Genetic; Genetic Transcription; Goals; Homologous Protein; In Vitro; Interneurons; Knowledge; Link; Mediating; Molecular; Molecular Genetics; Motor; Motor Neurons; Muscle; Nerve Regeneration; Nervous system structure; Neurodegenerative Disorders; Neurons; Nuclear; Parkinson Disease; Pathway interactions; Population; Proteolysis; Receptor Signaling; Regulation; Replacement Therapy; Research; Role; Signal Transduction; Signaling Molecule; Sorting - Cell Movement; Specific qualifier value; Specificity; System; Testing; Therapeutic; Transactivation; Transcript; Transcriptional Regulation; Translating; Work; axon guidance; base; developmental disease; gain of function; gamma secretase; gene function; genetic manipulation; in vivo; insight; islet; mRNA Expression; mutant; nervous system disorder; netrin receptor; new therapeutic target; novel; prevent; programs; promoter; public health relevance; receptor; repaired; research study; response; stem cells; transcription factor

PROJECT SUMMARY Determining how neurons are correctly specified and assembled into functional circuits will provide critical insight into developmental disorders of the nervous system and may suggest therapeutic approaches to promote nerve regeneration. To achieve this goal it is important to understand how axon responses to conserved families of axon guidance cues are regulated. Slit and Netrin, and their Robo and Fra/DCC receptors, are highly conserved signaling molecules that regulate multiple aspects of circuit development. Here, we propose to investigate how responses to Slit and Netrin are regulated by defining functional and molecular links between conserved transcriptional regulators that impart neuronal subtype identity and the cell surface axon guidance receptors for Slit and Netrin that coordinate motor and midline axon guidance. In addition, we propose to explore a newly discovered mechanism through which the Frazzled/DCC receptor intracellular domain (ICD) itself can regulate transcription to negatively regulate responses to the midline repellant Slit. The developing Drosophila embryonic CNS is an ideal system to explore transcriptional mechanisms that regulate axon guidance because of the availability of powerful genetic approaches and the evolutionary conservation of the transcription factors and cell surface receptors that coordinate circuit assembly. The aims of this proposal are to determine how the Slit receptor Robo2 and the Netrin receptor Frazzled (Fra) are regulated by transcription factors, including Hb9, Nkx6 and Islet, and how, in turn, this regulation instructs pathway selection in defined populations of motor and interneurons. We will also use FACs sorting of defined subsets of motor neurons, together with transcript profiling in wild type and mutant backgrounds, to systematically identify additional effectors of these transcriptional programs. Finally, using a combination of robust in vitro and in vivo genetic and biochemical strategies, we will evaluate the hypothesis that in order to promote midline crossing, the Fra receptor undergoes gamma-secretase dependent proteolysis to release an intracellular domain (ICD) fragment that translocates to the nucleus to regulate its target gene commissureless (a key negative regulator of midline repulsion). Our proposed research will inform studies of homologous proteins in mammalian systems and could provide pharmacologic and genetic strategies to manipulate the specification of neuronal subtypes and receptor signaling. Furthermore, the results of our research may suggest new therapeutic targets for diverse disorders of the nervous system.

项目摘要 确定如何正确指定神经元并组装到功能电路中 对神经系统的发育障碍提供批判性的见解，并可能暗示 促进神经再生的治疗方法。 为了实现这一目标，重要的是 了解如何调节轴突对轴突指导的保守家族的反应。 狭缝和网络以及它们的机器人和FRA/DCC受体是高度保守的信号传导 调节电路发育多个方面的分子。 在这里，我们建议 研究如何通过定义功能和分子来调节对裂缝和网络的反应 赋予神经元亚型身份的保守转录调节剂与 细胞表面轴突引导受体的狭缝和网络蛋白，以协调电动机和中线轴突 指导。 此外，我们建议探索一种新发现的机制 疲倦/DCC受体细胞内结构域（ICD）本身可以调节转录 调节对中线驱虫缝隙的响应。发展中的果蝇胚胎中枢神经系统是 探索转录机制的理想系统，以调节轴突指导 强大的遗传方法的可用性和对 转录因子和协调电路组装的细胞表面受体。 目的 该建议是确定狭缝受体Robo2和Netrin受体如何陷入困境的 （FRA）受转录因子的调节，包括HB9，NKX6和Islet，以及如何依次 调节指示运动和中间神经元定义种群中的途径选择。 我们将 还使用facs分类运动神经元的定义子集，以及在 野生型和突变背景，以系统地识别其中的其他效应子 转录程序。 最后，结合了强大的体外和体内遗传和 生化策略，我们将评估以下假设：为了促进中线 交叉，FRA受体经历γ-分泌酶依赖性蛋白水解释放 细胞内结构域（ICD）片段易位到核调节其靶基因 无委员会（中线排斥的关键负面调节者）。 我们提出的研究将 为哺乳动物系统中同源蛋白质的研究提供信息，并可以提供药理 以及操纵神经元亚型和受体规范的遗传策略 信号。 此外，我们的研究结果可能建议 神经系统的多种疾病。