Quantitative Genetic Study of Seizures

这项申请要求4年的资金，以继续在癫痫发作的遗传易感性研究的综合计划。这项工作的长期目标是确定近交系小鼠中的癫痫易感基因，并将其作为人类常见癫痫形式的重点研究的基础。在这个项目的初始阶段，我们使用数量性状基因座（QTL）定位来研究2个近交系小鼠品系的癫痫易感性：B6，这是对实验性癫痫发作的抗性，和D2，这是敏感的。这项工作的结果确定了一个位点的主要影响，Szs 1（chr. 1），和其他几个位点的中度影响，包括Szs 11（chr. 5）和Szs 13（chr. 15）。我们假设这些基因座的基因基本上是 在神经元兴奋性的调节中是重要的，因为它们在使用红藻氨酸、戊四唑和电击的不同筛选范例中被一致地检测到。因此，在过去的资助期内，我们主要通过同源株候选基因策略，进一步研究了这些基因座的特征。结果导致Szs 1基因的命名和Szs 11和Szs 13在同源菌株中的确认。假定的Szs 1基因是Kcnj 10，它编码一个内向整流钾通道，并计划产生正式的证据，它是Szs 1包括本建议的第一个目标。研究将涉及创建转基因和基因敲入小鼠，并将利用体内和体外电生理学以及癫痫易感性的行为测试。目标2涉及使用我们为Szs 1开发的原型策略继续改进Szs 11和Szs 13。因此，在完成上一个资助期开始的同源菌株和系统创建间隔特异性同源菌株的基础上，我们计划将临界间隔降低至3 cM，然后开始候选基因分析。第三个目标是启动新的QTL研究，旨在利用其他近交系小鼠表现出的表型多样性来鉴定癫痫易感性位点。总体而言，我们假设与小鼠癫痫易感性相关的遗传变异与人类常见癫痫的基础有关;此外，通过确定小鼠中的关键基因座，将更深入地了解人类癫痫发作及其消除的机制。我们实验室最近的数据记录了KCNJ 10变异体与特发性全身性癫痫之间的显著关联，支持这一概念，并证明继续使用QTL定位来鉴定小鼠癫痫易感性位点是合理的。

This application requesting 4 years of funding to continue a comprehensive program in the study of genetic susceptibility to seizures. The long term goal of this work is to identify seizure susceptibility genes in inbred mice and use them as the basis for focused studies in humans with common forms of epilepsy. In the initial stages of this project, we used quantitative trait locus (QTL) mapping to study seizure susceptibility in 2 inbred mouse strains: B6, which is resistant to experimental seizures, and D2, which is susceptible. Results of this work identified a locus of major effect, Szs1 (chr.1), and several other loci of moderate effect including Szs11 (chr. 5) and Szs13 (chr. 15). We hypothesize that the genes underlying these loci are fundamentally important in the regulation of neuronal excitability since they were detected consistently in diverse screening paradigms using kainic acid, pentylenetetrazol and electroshock. Thus, over the past funding period, we have focused on characterizing each of these loci further, primarily through a congenic strain-candidate gene strategy. Results have led to nomination of a gene for Szs1 and confirmation of Szs11 and Szs13 in congenic strains. The putative Szs1 gene is Kcnj10 which encodes an inward-rectifying potassium channel and plans to generate formal proof that it is Szs1 comprise the first aim of this proposal. Studies will involve creation of transgenic and knock-in mice and will utilize in vivo and in vitro electrophysiology as well as behavioral tests of seizure susceptibility. Aim 2 involves continued refinement of Szs11 and Szs13 using the prototype strategy we developed for Szs1. Thus, based on completion of congenic strains begun during the last funding period and systematic creation of interval specific congenic strains, we plan to reduce the critical intervals to 3 cM and then begin candidate gene analysis. The third aim involves initiation of new QTL studies designed to exploit the phenotypic diversity exhibited by other inbred mouse strains for identifying seizure susceptibility loci. Overall, we hypothesize that genetic variation associated with seizure susceptibility in mice is related to that which underlies common human epilepsies; and further, that by identifying key loci in mice greater insight will be afforded into mechanisms of seizures and their abolition in humans. Recent data from our lab documenting a significant association between variants of KCNJ10 and idiopathic generalized epilepsy support this concept and justify the continued use of QTL mapping for identifying seizure susceptibility loci in mice.