Genetic and Developmental Analyses of Fragile X Syndrome

脆性 X 综合征的遗传和发育分析

• 批准号: 7730869
• 负责人: Kendal Broadie
• 金额: $ 53.22万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7730869
• 关键词: Activity Cycles; Animal Model; Architecture; Autistic Disorder; Behavior; Behavioral; Biological Assay; Brain; Brain Diseases; Brain region; Cholinergic Receptors; Circadian Rhythms; Classification; Complex; Defect; Development; Disease; Drosophila FMR1 protein; Drosophila genus; Electrophysiology (science); Excitatory Amino Acid Antagonists; FMR1 Gene; Fragile X Mental Retardation Protein; Fragile X Syndrome; Genetic; Genetic Models; Genetic Screening; Glutamates; Human; Image; Inherited; Intervention; Learning Disabilities; Life; Maintenance; Mediating; Memory; Mental Retardation; Messenger RNA; Metabotropic Glutamate Receptors; Modality; Modeling; Molecular; Molecular Genetics; Monitor; Motor Activity; Movement; Mus; Mushroom Bodies; Neurons; Neurotransmitter Receptor; Neurotransmitters; Olfactory Learning; Output; Pathway interactions; Patients; Pattern; Performance; Pharmaceutical Preparations; Phosphorylation; Protein Binding; Proteins; Proteomics; RNA Binding; Receptor Signaling; Regulation; Relative (related person); Role; Screening procedure; Sensory; Signal Transduction; Staging; Structure; Switch Genes; Synapses; System; Technology; Testing; Therapeutic Intervention; Time; Transgenic Animals; Transgenic Organisms; Translations; Work; autism spectrum disorder; base; behavioral impairment; cholinergic; circadian pacemaker; design; developmental genetics; gain of function; human disease; in vivo; insight; loss of function; mutant; neural circuit; neurotransmission; optical imaging; protein expression; protein function; public health relevance; receptor; relating to nervous system; synaptic function; tool; trafficking; treatment strategy

DESCRIPTION (provided by applicant): Fragile X Syndrome (FraX) is a developmental brain disorder with abnormal neuron architecture development and functional plasticity of the developing brain, causing mental retardation, learning disabilities and autism. My lab established the Drosophila FraX model and proved it provides direct insights into molecular and cellular bases of the human disease state. In this revised proposal, I ask your support to take advantage of this model, and the relative simplicity of the Drosophila brain, to test core hypotheses of FraX and interventions to correct brain defects. First, I will test the temporal requirements for the Fragile X Mental Retardation Protein (FMRP) in defined brain neural circuit formation and the maintained manifestation of normal behaviors from these circuits. I target two extremely well-defined brain circuits; 1) the circadian clock circuit that regulates regular motor activity cycles, and 2) the mushroom body (MB) circuit that mediates olfactory learning/memory consolidation. This aim will characterize the development of these circuits and their synaptic connectivity in the presence vs. absence of FMRP. A transgenic conditional FMRP expression system will be used to test the hypothesis that FMRP is required specifically during a transient period of neural circuit development to establish maintenance of normal behaviors. Transgenic animals expressing FMRP during discrete developmental windows will be tested for anatomical neural circuit formation, synaptic structure and function, and the behavior outputs of circadian activity and olfactory learning and memory consolidation. Second, I will test the hypothesized role of FMRP in sensory modality, electrical and synaptic neurotransmission activity-dependent changes in brain neural circuit development. The interaction between FMRP function and brain circuit activity will be assayed in double mutant combinations and with an array of proven transgenic tools that either increase or decrease electrical activity in targeted brain regions. The specific role of metabotropic neurotransmitter receptor signaling will be assayed in both cholinergic and glutamatergic brain regions using a combination of genetic mutants and pharmacological studies. The temporal roles of these pathways will be assessed with timed application of drugs during defined stages of brain development to define temporal windows for therapeutic intervention. The role of FMRP in local translation control downstream of a neurotransmission activity-induced phosphorylation will be tested by making transgenic constitutively phosphorylated or desphosphorylated mimic proteins. It is imperative to appreciate that these hypothesized functions have never been tested in vivo, in an animal model. Third, I will use new proteomic technologies to screen for brain protein changes occurring during specific periods of brain development, in the presence and absence of FMRP. In parallel, systematic forward genetic screens will be pursued to directly identify dfmr1 genetic interactors. Together, these aims are designed to make maximal use of the proven Drosophila FraX genetic model. I am the only one poised to pursue this work and truly believe that I can aid enormously in the understanding and treatment of Fragile X Syndrome. PUBLIC HEALTH RELEVANCE: Fragile X Syndrome is a developmental brain disorder that is the most commonly inherited form of both mental retardation and autism spectrum disorders. This proposal studies the molecular and cellular basis of this disease in the developing brain and directly tests therapeutic interventions aimed at correcting the brain developmental abnormalities.

描述（由申请人提供）：脆性X综合征（FraX）是一种发育性脑障碍，具有发育中脑的异常神经元结构发育和功能可塑性，导致智力迟钝、学习障碍和自闭症。我的实验室建立了果蝇FraX模型，并证明它可以直接洞察人类疾病状态的分子和细胞基础。在这个修订后的提案中，我请求您的支持，以利用这个模型，以及果蝇大脑的相对简单性，来测试FraX的核心假设和纠正大脑缺陷的干预措施。首先，我将测试脆性X智力迟钝蛋白（FMRP）在确定的大脑神经回路形成和维持这些回路的正常行为表现中的时间要求。我的目标是两个非常明确的大脑回路：1）调节规律运动活动周期的生物钟回路，2）介导嗅觉学习/记忆巩固的蘑菇体（MB）回路。这一目标将表征这些回路的发展及其在存在与不存在FMRP的情况下的突触连接。转基因条件FMRP表达系统将被用来测试这一假设，即FMRP是需要特别是在一个短暂的时期的神经回路的发展，以建立正常行为的维护。将测试在离散发育窗期间表达FMRP的转基因动物的解剖神经回路形成、突触结构和功能以及昼夜节律活动和嗅觉学习和记忆巩固的行为输出。其次，我将测试的假设作用FMRP在感觉的方式，电和突触神经传递活动依赖的变化，在大脑神经回路的发展。FMRP功能和脑回路活动之间的相互作用将在双突变体组合中进行测定，并使用一系列经过验证的转基因工具，这些工具可以增加或减少目标脑区域的电活动。代谢型神经递质受体信号传导的特定作用将在胆碱能和多巴胺能脑区使用遗传突变体和药理学研究的组合进行测定。这些途径的时间作用将通过在大脑发育的确定阶段期间定时应用药物来评估，以确定治疗干预的时间窗。FMRP在神经传递活性诱导的磷酸化下游的局部翻译控制中的作用将通过制备转基因组成型磷酸化或去磷酸化模拟蛋白来测试。必须认识到，这些假设的功能从未在动物模型中进行过体内测试。第三，我将使用新的蛋白质组学技术来筛选在大脑发育的特定时期，在存在和不存在FMRP的情况下发生的大脑蛋白质变化。与此同时，将进行系统的正向遗传筛选，以直接鉴定dfmr 1遗传相互作用因子。总之，这些目标旨在最大限度地利用经验证的果蝇FraX遗传模型。我是唯一一个准备从事这项工作的人，并且真正相信我可以极大地帮助理解和治疗脆性X综合征。公共卫生相关性：脆性X综合征是一种发育性脑障碍，是智力迟钝和自闭症谱系障碍中最常见的遗传形式。该提案研究了这种疾病在大脑发育中的分子和细胞基础，并直接测试旨在纠正大脑发育异常的治疗干预措施。