QUANTITATIVE GENETIC STUDY OF SEIZURES

癫痫发作的定量遗传学研究

• 批准号: 2271914
• 负责人: THOMAS N FERRARO
• 金额: $ 20.9万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-05 至 1997-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2271914
• 关键词: animal genetic material tag; dinucleotide; electronic stimulator; epilepsy; genetic markers; kainate; kindling; laboratory mouse; linkage mapping; molecular genetics; nucleic acid repetitive sequence; pentylenetetrazole; pharmacogenetics; polymerase chain reaction

Mature DBA/2J and C57BL/6J mice differ significantly in susceptibility to seizures induced by various physical and chemical stimuli. In general, DBA mice are characterized as relatively "seizure sensitive" and C57 mice are characterized as relatively "seizure resistant". This proposal describes a research project intended to elucidate genomic loci which contribute to the large differences observed between mature C57BL/6J and DBA/2J mice in susceptibility to seizures induced by kainic acid (KA), pentylenetetrazole (PTZ), and maximal electroshock (MES) treatment. It is hypothesized that strain-dependent sensitivity and resistance to aspects of the convulsive response induced by these treatments are mediated by similar genetic elements. In three distinct experiments, B6D2F1 /J (C57BL/6J x DBA/2J, F1 generation) mice will be bred in intercross to produce F2 generations of approximately 500 mice. In each experiment, F2 mice will be studied for seizure phenotype. Behavioral seizure parameters-to be monitored following administration of chemoconvulsants include latency to first seizure (clonus) latency to generalized (tonic-clonic) seizure and number of discrete seizures. In the KA study, induction of and latency to status epileptic us will also be monitored. These parameters will be used to quantify seizure activity in each animal. An overall seizure score will be generated by applying a weighted scale to the quantitative seizure measures. In the third series of experiments, phenotypes will reflect MES threshold for tonic hindlimb extension. The quantitative trait loci (QTL) strategy of "intervals and extremes" will be employed in which F2 progeny exhibiting the 10% most extreme phenotypes (the highest and lowest seizure severity scores or MES thresholds) will be selected for use in genotype experiments. Genotyping will be conducted using PCR-based microsatellite (dinucleotide/simple sequence repeat) DNA markers evenly spaced at 10 cM intervals across the entire mouse genome. Employing a computer program for maximum likelihood methods, MAPMAKER/QTL, genotype data will be analyzed to identify the approximate chromosomal locations of genes contributing to KA and PTZ seizure susceptibility in DBA/2J mice, KA and PTZ seizure resistance in C57BL/6J mice and the difference between the strains in MES threshold. In KA and PTZ studies, separate QTL calculations will be carried out for individual components of the seizure severity score (such as latency to clonus and status epileptic us) as well as for the total seizure score. MES thresholds will be used directly in QTL calculations. Confirmation that similar genetic loci are associated with susceptibility and resistance to specific effects of the described convulsive treatments would indicate the localization of genes important for the regulation of excitability in mouse brain. Identification of these genes could ultimately lead to major advances in understanding and treating human epilepsies.

成熟的DBA/2J和C57BL/6J小鼠的敏感性显着不同 各种物理和化学刺激引起的癫痫发作。总体而言，DBA 小鼠的特征是相对“癫痫敏感”，C57小鼠是 被描述为相对“抗癫痫发作”。该提案描述了 一个旨在阐明基因组基因座的研究项目，有助于 在成熟的C57BL/6J和DBA/2J小鼠中观察到的很大差异 海藻酸（KA）诱导的癫痫发作的敏感性 （PTZ）和最大电笔（MES）处理。假设 因应变依赖性敏感性和对抽搐方面的抗性 这些治疗引起的反应是通过相似遗传介导的 元素。在三个不同的实验中，B6D2F1/j（C57BL/6J X DBA/2J，F1 一代）小鼠将在跨跨中繁殖，以产生F2代 大约500只小鼠。在每个实验中，将研究F2小鼠 癫痫发作表型。行为癫痫发作参数可监视以下 化学弹飞剂的给药包括首次癫痫发作的潜伏期 （clonus）广泛性（补体）癫痫发作的潜伏期和数量 离散癫痫发作。在KA研究中，归纳和状态潜伏期 还将监测癫痫发作的美国。这些参数将用于 量化每只动物的癫痫发作活性。总体癫痫发作分数将是 通过将加权量表应用于定量癫痫发作而产生 措施。在第三个实验中，表型将反映MES 补品后肢扩展的阈值。定量性状基因座（QTL） 将采用“间隔和极端”的策略，其中F2后代 表现出10％最极端的表型（最高和最低的癫痫发作 将选择用于基因型的严重性评分或MES阈值） 实验。基因分型将使用基于PCR的微卫星进行 （二核苷酸/简单序列重复）DNA标记在10 cm处均匀间隔 整个小鼠基因组的间隔。 采用计算机程序 对于最大似然方法，MAPMAKER/QTL，基因型数据将是 分析以识别基因的近似染色体位置 在DBA/2J小鼠，KA和 C57BL/6J小鼠中的PTZ癫痫发作抗性以及 MES阈值中的菌株。在KA和PTZ研究中，单独的QTL计算 将针对癫痫发作严重程度的单个组件进行 得分（例如clonus和状态癫痫的延迟）以及 总癫痫发作得分。 MES阈值将直接在QTL中使用 计算。确认相似的遗传基因座与 对所描述的特定效应的敏感性和抵抗力 抽搐治疗将表明基因的定位很重要 用于调节小鼠大脑中的兴奋性。确定这些 基因最终可能导致理解和 治疗人类癫痫病。