Mechanism of Sonic hedgehog-induced axon growth and guidance

声波刺猬诱导轴突生长和引导的机制

• 批准号: 7223112
• 负责人: Adrianne Lynn Kolpak
• 金额: $ 2.72万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-12 至 2010-01-11
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7223112
• 关键词: Affect; Antibodies; Autistic Disorder; Axon; Binding; Binding Proteins; Biological Models; Brain; Co-Immunoprecipitations; Cues; Cytoplasmic Tail; Development; Epilepsy; Erinaceidae; Genetic Transcription; Growth; Laboratories; Lead; Mediating; Membrane; Messenger RNA; Mission; Molecular; Nerve; Nervous System Physiology; Neurons; Numbers; Process; Proteins; Receptor Signaling; Regulation; Reporting; Research; Retinal Ganglion Cells; Signal Pathway; Signal Transduction; Signaling Protein; Sonic hedgehog protein; Spinal cord injury; System; Yeasts; axon growth; axon guidance; expression cloning; human SMO protein; intracellular protein transport; nervous system disorder; neural circuit; novel; protein localization location; receptor; research study; response; smoothened signaling pathway; therapy development; yeast two hybrid system

DESCRIPTION (provided by applicant): The objective of this proposal is to understand the mechanism by which the protein, Sonic hedgehog (Shh), acts in a concentration-dependent manner to regulate retinal ganglion cell axon growth and guidance. Specifically, the receptor(s) to which Shh binds will be investigated to determine if the response to both low and high concentrations of Shh is mediated by one receptor or two different receptors, which has been reported for the concentration-dependent response of axons to the guidance factor, Wnt3. A co-immunoprecipitation experiment will be performed using tagged Shh protein to identify all candidate receptors to which Shh binds on axons. Expression of candidate receptors on axons will be investigated followed by functional studies to determine if the receptors are required for the growth response of axons to Shh. Proteins that interact with the Shh signaling protein, Smoothened (Smo), will also be investigated. It has been shown that Smo is required for transducing the axon growth responses at both low and high concentrations and Smo binding proteins are required for transducing the hedgehog signal in other systems. To identify binding partners in axons, co-immunoprecipitation experiments using an anti-Smo antibody and a yeast two-hybrid screen using the cytoplasmic tail of Smo as bait will be performed. Examining Shh signaling at both the receptor and downstream signaling levels will lead to a better understanding of the molecular mechanisms by which Shh affects axon growth in a concentration-dependent manner and, more generally, how axon guidance factors may direct axon growth. Overall, the proposed research relates to the mission of the NINDS in that it will lead to a better understanding of how the neural circuitry is established during development, a process that is critical for all neurological functions. Also, it may aid in the development of therapies for spinal cord injuries, in which axons are irreparably damaged, and lead to a better understanding of neurological disorders that may result from abnormal circuit formation, including epilepsy and autism. Understanding the mechanisms that regulate axon growth during development will be important in developing therapies for spinal cord injuries, in which nerve connections are damaged and for which there is currently no cure. Also, it has been suggested that some neurological disorders, including autism and epilepsy, may result from abnormal circuit formation during brain development. Therefore, researching how axons grow will be critical for identifying the causes of some neurological disorders and in developing a cure for people with debilitating spinal cord injuries.

描述(由申请人提供)：本提案的目的是了解Sonic hedgehog(Shh)蛋白以浓度依赖的方式调节视网膜神经节细胞轴突生长和引导的机制。具体地说，将研究Shh结合的受体(S)，以确定对低浓度和高浓度Shh的反应是由一个受体还是两个不同的受体介导的，这已被报道为轴突对引导因子WNT3的浓度依赖反应。将使用标记的Shh蛋白进行免疫共沉淀实验，以确定Shh与轴突上的所有候选受体结合。将研究轴突上候选受体的表达，然后进行功能研究，以确定这些受体是否是轴突对Shh的生长反应所必需的。与Shh信号蛋白Smoothens(Smo)相互作用的蛋白质也将被研究。已有研究表明，在低浓度和高浓度下，轴突生长反应的转导都需要Smo，而在其他系统中，转导Hedgehog信号需要Smo结合蛋白。为了确定轴突中的结合伙伴，将进行使用抗Smo抗体的免疫共沉淀实验和以Smo细胞质尾巴为诱饵的酵母双杂交筛选。在受体和下游信号水平上研究Shh信号将有助于更好地理解Shh以浓度依赖的方式影响轴突生长的分子机制，以及更广泛地说，轴突引导因子如何指导轴突生长。总体而言，拟议的研究与NINDS的使命有关，因为它将导致更好地理解神经回路是如何在发育过程中建立的，这一过程对所有神经功能都至关重要。此外，它还可能有助于开发脊髓损伤的治疗方法，在脊髓损伤中，轴突受到不可修复的损害，并有助于更好地理解可能由异常电路形成引起的神经障碍，包括癫痫和自闭症。了解在发育过程中调节轴突生长的机制对于开发脊髓损伤的治疗方法将是重要的，脊髓损伤中的神经连接受到破坏，目前还没有治愈的方法。此外，有人提出，一些神经疾病，包括自闭症和癫痫，可能是由于大脑发育过程中异常的电路形成造成的。因此，研究轴突是如何生长的，对于确定一些神经疾病的原因，以及开发治疗虚弱脊髓损伤的方法至关重要。