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.

项目总结 确定神经元如何被正确地指定和组装成功能电路将 提供对神经系统发育障碍的批判性见解，并可能建议 促进神经再生的治疗方法。为了实现这一目标，重要的是 了解轴突对保守的轴突引导线索家族的反应是如何调节的。 Sit和Netrin以及它们的Robo和Fra/DCC受体是高度保守的信号 调节电路发展的多个方面的分子。在此，我们建议 通过定义功能和分子，研究对Sit和Netrin的反应是如何调节的 给予神经元亚型识别的保守转录调控因子与 协调运动和中线轴突的Sit和Netrin细胞表面轴突引导受体 指导。此外，我们建议探索一种新发现的机制，通过这种机制， FRAMZLED/DCC受体胞内结构域(ICD)本身可以负向调节转录 调节对中线驱避剂缝隙的反应。发育中的果蝇胚胎中枢神经系统 探索调节轴突引导的转录机制的理想系统，因为 强大的遗传方法的可获得性和物种的进化守恒 转录因子和细胞表面受体，协调电路组装。的目标是 这项建议是为了确定缝隙受体Robo2和Netrin受体是如何磨损的 (FRA)受转录因子调控，包括HB9、NKX6和Islet，以及这反过来是如何 调节指导运动神经元和中间神经元的特定群体中的路径选择。我们会 还使用FACS对定义的运动神经元子集进行分类，以及 野生型和突变型背景，以系统地识别这些的其他效应器 转录程序。最后，结合使用体外和体内的强大遗传和 生化策略，我们将评估假设，以促进中线 交叉后，Fra受体经历依赖于伽马分泌酶的蛋白分解，释放出 胞内结构域(ICD)片段，移位到细胞核以调节其靶基因 无通行证(中线斥力的关键负面调节因素)。我们提议的研究将 为哺乳动物系统中同源蛋白的研究提供信息，并可以提供药理学 以及操纵神经元亚型和受体规格的遗传策略 发信号。此外，我们的研究结果可能会提出新的治疗靶点 神经系统的各种紊乱。