The Genetics and Cell Biology of the Epileptic Mouse Mutant Fitful

癫痫小鼠突变体的遗传学和细胞生物学

基本信息

批准号：
8269863
负责人：
REBECCA M BOUMIL
金额：
$ 31.45万
依托单位：
JACKSON LABORATORY
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-06-01 至 2015-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8269863
关键词：
Address Affect Age Age-Months Alleles Alternative Splicing Amino Acid Substitution Animal Genetics Anticonvulsants Antiepileptic Agents Ataxia Auxilins Biochemical Biological Assay Brain Canis familiaris Cellular biology Centronuclear myopathy Charcot-Marie-Tooth Disease Clathrin Collection Complex Data Defect Diagnosis Disease Dominant-Negative Mutation Dynamin Dynamin I Electroencephalography Electron Microscopy Endocytosis Environment Epilepsy Epileptogenesis Equilibrium Event Exercise Exocytosis Exons Functional disorder Future Gene Mutation Generations Genes Genetic Genets Goals Guanosine Triphosphate Phosphohydrolases Hippocampus (Brain)Homo Homologous Gene Homozygote Human Image Ion Channel Left Link Measurement Mediating Membrane Membrane Proteins Missense Mutation Modeling Molecular Molecular and Cellular Biology Monitor Mouse Strains Mus Mutant Strains Mice Mutate Mutation Neurologic Neurons Outcome Pathway interactions Pharmaceutical Preparations Phenotype Play Predisposition Process Protein Isoforms Proteins RNA Splicing Recurrence Recycling Regulation Research Role Seizures Severities Staging Synapses Synaptic Transmission Synaptic Vesicles Syndrome Time Transgenic Organisms Vesicle amphiphysin base experience improved in vivo Model insight intersectin 1 mutant nervous system disorder neurotransmission novel novel strategies programs protein protein interaction synaptojanin treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Epilepsy is a collection of disorders that causes recurrent seizures. Often it is not the fault of a single gene but of complex genetic interactions. Each year, 200,000 new cases of epilepsy are diagnosed. In seventy percent of these cases there is no apparent cause. It is estimated that ten percent of these "new" cases will never obtain adequate seizure control even with treatment. Currently, the major focus of research is on improving and devising anticonvulsant medications, but the underlying mechanisms need to be uncovered and better understood to improve treatment strategies. To date, most of the known epilepsy genes are monogenic and responsible for human autosomal dominant forms of the disease. The more complex epilepsies are likely the result of polygenic interactions and environment. Our long-term goal is to elucidate the mechanisms by which a mutation in the Dynamin-1 (Dnm1) gene causes a complex seizure disorder. Dnm1 encodes a large multimeric GTPase necessary for activity-dependent membrane recycling in neurons, including synaptic vesicle endocytosis. Mice heterozygous for a novel spontaneous Dnm1 mutation - fitful - experience recurrent seizures, and homozygotes have more debilitating, often lethal seizures in addition to severe ataxia and neurosensory deficits. Fitful is a missense mutation in an exon that defines the Dnm1a isoform, leaving intact the alternatively spliced exon that encodes Dnm1b. We hypothesize that in fitful mice endocytosis is stalled at a checkpoint that requires the proper function of the Dnm1 isoforms to proceed from early endocytic events to later stage fission events. A delay in synaptic vesicle endocytosis would result in a deficiency of readily available vesicles for neurotransmission. Using fitful as a model of epilepsy, the following Specific Aims are proposed to address genetic questions related to the endocytic checkpoint: 1) Determine the genetic interactions involved in the endocytic checkpoint. We will use genetically disrupted mouse mutant strains of genes known to interact with Dnm1 at different stages of endocytosis to ask how disruption of endocytosis/fission at different points affects seizure phenotype differentially. 2) Dissect the potentially overlapping roles of the Dnm1 alternatively spliced isoforms in the checkpoint resulting in the seizure phenotype. Studies will utilize Dnm1 isoform specific mouse lines for animal genetic and seizure phenotype analysis. Collectively, these studies will define the involvement of Dnm1 in synaptic vesicle endocytosis. Additionally, they will give insight into the role that genes encoding endocytic proteins play in contributing to epilepsy. We suggest that using an in vivo model of dynamin dysfunction, such as fitful, will answer important questions not only about how dynamin functions in endocytosis, but also the important role dynamin plays in proper synaptic transmission.

描述（由申请人提供）：癫痫是导致反复发作的疾病的集合。通常这不是单个基因的错误，而是复杂的遗传相互作用的错误。每年新诊断出 20 万例癫痫病例。百分之七十的病例没有明显的原因。据估计，即使经过治疗，这些“新”病例中的百分之十也永远无法充分控制癫痫发作。目前，研究的主要焦点是改进和设计抗惊厥药物，但需要揭示和更好地理解其潜在机制，以改进治疗策略。迄今为止，大多数已知的癫痫基因都是单基因的，并且导致该疾病的人类常染色体显性形式。更复杂的癫痫可能是多基因相互作用和环境的结果。我们的长期目标是阐明 Dynamin-1 (Dnm1) 基因突变导致复杂癫痫症的机制。 Dnm1 编码一种大型多聚体 GTP 酶，是神经元中活性依赖性膜回收所必需的，包括突触小泡内吞作用。携带新型自发 Dnm1 突变的杂合子小鼠会反复发作癫痫发作，而纯合子小鼠除了严重的共济失调和神经感觉缺陷外，还会出现更严重的衰弱甚至致命的癫痫发作。 Fitful 是定义 Dnm1a 同工型的外显子中的错义突变，使编码 Dnm1b 的选择性剪接外显子保持完整。我们假设，在断断续续的小鼠中，内吞作用在一个检查点停滞，需要 Dnm1 同种型的适当功能才能从早期内吞事件进行到后期裂变事件。突触小泡内吞作用的延迟将导致神经传递中可用的小泡的缺乏。使用间歇性作为癫痫模型，提出以下具体目标来解决与内吞检查点相关的遗传问题：1）确定内吞检查点涉及的遗传相互作用。我们将使用已知在不同的内吞阶段与 Dnm1 相互作用的基因被破坏的小鼠突变株来探究不同点的内吞/裂变的破坏如何对癫痫表型产生不同的影响。 2) 剖析导致癫痫表型的检查点中 Dnm1 选择性剪接亚型的潜在重叠作用。研究将利用 Dnm1 亚型特异性小鼠品系进行动物遗传和癫痫表型分析。总的来说，这些研究将明确 Dnm1 在突触小泡内吞作用中的参与。此外，他们还将深入了解编码内吞蛋白的基因在导致癫痫中所起的作用。我们建议，使用动力功能障碍的体内模型，例如间歇性的，不仅可以回答有关动力如何在内吞作用中发挥作用的重要问题，而且可以回答动力在适当的突触传递中发挥的重要作用。