Quantitative Genetic Study of Seizures

这项申请要求4年的资金，以继续进行癫痫遗传易感性研究的全面计划。这项工作的长期目标是识别近交系小鼠的癫痫易感性基因，并将其用作对患有常见形式癫痫的人类进行重点研究的基础。在这个项目的初始阶段，我们使用数量性状基因座(QTL)定位来研究两个近交系小鼠的癫痫易感性：B6，它对实验性癫痫具有抵抗力，而D2，它是易感的。这项工作的结果确定了一个主效基因Szs1(chr.1)，以及包括Szs11(chr.5)和Szs13(Chr.15)。我们假设，这些基因座背后的基因基本上是 在调节神经元兴奋性方面很重要，因为它们在使用红藻氨酸、戊四氮和电击的不同筛查范例中被一致检测到。因此，在过去的资助期间，我们主要通过同源菌株候选基因策略，专注于进一步确定这些基因座的特征。结果导致了Szs1基因的提名，并确认了Szs11和Szs13在同源菌株中的存在。推测的Szs1基因是Kcnj10，它编码一个内向整流钾通道，并计划产生正式的证据，证明它是Szs1，这是本提案的第一个目的。研究将包括创造转基因和敲入小鼠，并将利用体内和体外电生理学以及癫痫敏感性的行为测试。目标2涉及使用我们为Szs1开发的原型策略对Szs11和Szs13进行持续改进。因此，基于上一次资助期间开始的同源菌株的完成和有系统地创建区间特定的同源菌株，我们计划将临界区间减少到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品系表现出的表型多样性来识别癫痫易感基因。总体而言，我们假设与小鼠癫痫易感性相关的基因变异与人类常见癫痫的基础有关；此外，通过识别小鼠的关键基因座，我们将更深入地了解人类癫痫发作和废除的机制。来自我们实验室的最新数据记录了KCNJ10变异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定位来识别小鼠的癫痫易感基因。

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.