Transciption Factor Codes, Guidance Receptors and Motor Axon Guidance

转录因子代码、引导受体和运动轴突引导

• 批准号: 7459426
• 负责人: Greg J. Bashaw
• 金额: $ 31.5万
• 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 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7459426
• 关键词: Address; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Axon; Biochemical Genetics; Brain; Candidate Disease Gene; Cells; Cereals; Chromosome Deletion; Class; Code; Cues; Data; Defect; Dorsal; Dose; Drosophila genus; Embryo; Embryonic Nervous System; Enhancers; Exhibits; Fluorescence-Activated Cell Sorting; Genes; Genetic; Genetic Screening; Genetic Transcription; Homeobox; Individual; Invertebrates; Label; Link; Messenger RNA; Modeling; Molecular; Molecular Genetics; Motor; Motor Neuron Disease; Motor Neurons; Muscle; Mutate; Natural regeneration; Nerve Regeneration; Nervous system structure; Neurons; Pathway interactions; Penetrance; Personal Satisfaction; Phenotype; Population; Public Health; Range; Regulation; Repression; Research; Role; Screening procedure; Specific qualifier value; Spinal cord injury; Techniques; Testing; Therapeutic; Transcriptional Activation; Transcriptional Regulation; Up-Regulation; axon guidance; cDNA Arrays; combinatorial; design; developmental disease; gain of function mutation; gene function; genetic manipulation; homeodomain; islet; mRNA Expression; mutant; nervous system disorder; netrin receptor; receptor; receptor expression; research study; stem cell therapy; transcription factor

DESCRIPTION (provided by applicant): Understanding how distinct classes of motor neurons are specified and guided to appropriate muscle domains is of fundamental importance to the design of therapeutic approaches to nerve regeneration and motor neuron disease. It is well established that combinatorial codes of transcription factors dictate motor axon pathway selection in both vertebrate and invertebrate nervous systems; however, the downstream targets of these transcription factor codes that control axon guidance are poorly defined. This proposal seeks to define functional links between transcriptional regulators of motor axon guidance and specific axon guidance receptors that control path finding. The Drosophila embryonic nervous system is an attractive model in which to address these questions because of the ability to label and genetically manipulate individual and uniquely identified motor neurons. In addition, many of the key transcriptional regulators as well as the guidance cues and receptors are evolutionarily conserved; thus, findings in Drosophila are very likely to be directly relevant to higher vertebrate nervous systems. The major aims of this proposal are: 1) to determine whether the even-skipped homeobox transcription factor directly or indirectly regulates the expression of the Unc-5 axon guidance receptor to guide motor axons dorsally, 2) to determine whether the Slit receptor Robo2's influence on motor axons that project to ventral muscle targets reflects a functional link with the transcriptional regulation of ventral projection, and 3) to identify additional downstream targets of the transcriptional regulators of dorsal motor axon pathway selection using complementary genetic and molecular screening approaches. Classical genetic and biochemical techniques, including genetic interaction tests, mutant analysis, and mis-expression experiments will be used to investigate the role of Slit and Netrin receptors in contributing to the readout of the transcriptional code for motor axon guidance. To identify additional determinants of dorsal motor axon projection, we will take advantage of dose-dependent effects of mis-expressing even-skipped to 1) perform genetic screens for dominant enhancers and suppressors of this mis-expression phenotypes and 2) perform mRNA expression screens using candidate genes and cDNA microarrays for genes that are differentially regulated by even-skipped in purified populations of dorsally projecting motor neurons. PUBLIC HEALTH RELEVANCE: The proposed research has the potential to make important contributions to the understanding of developmental disorders of the nervous system and may suggest new strategies to promote regeneration after brain and spinal cord injury. In addition, a more complete understanding of how neurons develop and form specific connections will be invaluable for developing stem cell therapies for neuronal replacement to treat neurological disorders ranging from Alzheimer's disease to Amyotrophic Lateral Sclerosis.

描述（由申请人提供）：了解如何指定不同类别的运动神经元并将其引导至适当的肌肉域对于设计神经再生和运动神经元疾病的治疗方法至关重要。众所周知，转录因子的组合编码决定了脊椎动物和无脊椎动物神经系统中运动轴突通路的选择。然而，这些控制轴突引导的转录因子代码的下游目标尚不清楚。该提案旨在定义运动轴突引导的转录调节因子和控制路径寻找的特定轴突引导受体之间的功能联系。果蝇胚胎神经系统是解决这些问题的一个有吸引力的模型，因为它具有标记和基因操纵个体和独特识别的运动神经元的能力。此外，许多关键的转录调节因子以及引导信号和受体在进化上都是保守的。因此，果蝇的发现很可能与高等脊椎动物的神经系统直接相关。该提案的主要目的是：1）确定偶数跳跃同源盒转录因子是否直接或间接调节 Unc-5 轴突引导受体的表达以引导运动轴突背侧，2）确定 Slit 受体 Robo2 对投射到腹侧肌肉目标的运动轴突的影响是否反映了与腹侧投射转录调节的功能联系，以及 3）确定 使用互补遗传和分子筛选方法选择背侧运动轴突通路的转录调节因子。经典的遗传和生化技术，包括遗传相互作用测试、突变分析和错误表达实验，将用于研究 Slit 和 Netrin 受体在读出运动轴突引导转录代码中的作用。为了确定背侧运动轴突投射的其他决定因素，我们将利用错误表达偶数跳跃的剂量依赖性效应来1）对这种错误表达表型的显性增强子和抑制子进行遗传筛选，2）使用候选基因和cDNA微阵列对背侧投射运动神经元纯化群体中偶数跳跃差异调节的基因进行mRNA表达筛选。公共健康相关性：拟议的研究有可能为理解神经系统发育障碍做出重要贡献，并可能提出促进脑和脊髓损伤后再生的新策略。此外，更全面地了解神经元如何发育和形成特定连接对于开发用于神经元替代的干细胞疗法以治疗从阿尔茨海默病到肌萎缩侧索硬化症等神经系统疾病至关重要。