Rapid identification of cocaine sensitivity genes using a novel reduced complexity cross

摘要 物质使用障碍（SUD）导致发病率和死亡率的风险增加，并对健康造成重大影响。 对受影响的个人和整个社会造成的个人和经济负担。有相当多的证据 遗传学增加了SUD的风险，但识别特定的基因变异受到疾病的阻碍， 异质性、遗传复杂性和无法控制或解释人类环境暴露 人口。其中一些问题可以通过在啮齿动物模型中进行成瘾遗传研究来克服。然而，在这方面， 在啮齿动物群体中作图的标准方法通常导致鉴定大的基因组区域， 需要相当大的努力来缩小并因此延迟或阻止致病基因变体的鉴定。最近 技术和生物信息资源使利用杂交进行遗传作图研究成为可能 在近交系小鼠亚系之间（称为简化复杂性杂交或RCC）。近交系小鼠 当近交系育种菌落在合作者或商业实体之间转移时，会产生分歧。 多态性在这些亚群之间在基因组区域分离，亲本菌株 还没有固定下来，或者来自遗传漂变，导致遗传上非常密切相关的菌株。 因此，虽然标准近交系在数十万个基因座上彼此不同，但近交亚系 在数千个位点上存在差异-其中只有一小部分是功能性的。这些特征加快了识别 表型差异存在的亚株中的致病基因。这种方法已被用来确定一个 可卡因敏感基因，但已限于C57BL/6亚株。存在着几十种近亲繁殖的亚株， 鉴定影响成瘾相关行为的基因的机会正在被错过。我们有 发现C3H亚株C3H/HeJ之间可卡因运动敏感性的显著表型差异 和C3H/HeNTac。在该R21应用中，我们提出使用RCC来鉴定用于R21的致病等位基因。 这些亚株的表型差异。我们还将研究底物特异性药代动力学和剂量 反应表型，并检查奖励和加强可卡因的作用，使用药物自我- 管理范式这些研究将建立每种C3H亚株的药物反应特征， 我们开始探索因果等位基因改变行为的机制。

ABSTRACT Substance use disorders (SUD) result in increased risk of morbidity and mortality and impose substantial personal and financial burdens on affected individuals and society as a whole. There is considerable evidence that genetics increases the risk for SUDs, but identifying specific gene variants has been hampered by disease heterogeneity, genetic complexity and the inability to control or account for environmental exposures in human populations. Some of these issues can be overcome with addiction genetic studies in rodent models. However, standard methods of mapping in rodent populations often result in identification of large genomic regions that require considerable effort to narrow and thus delay or prevent identification of the causal gene variant. Recent technology and bioinformatic resources have made it possible to conduct genetic mapping studies using crosses between inbred mouse substrains (called Reduced Complexity Crosses or RCCs). Inbred mouse substrains diverge when inbred strain breeding colonies are transferred between collaborators or commercial entities. Polymorphisms segregate between these subpopulations at regions of the genome for which the parental strain has not yet become fixed, or from genetic drift, resulting in sets of strains that are genetically very closely related. Therefore, while standard inbred strains differ from each other at hundreds of thousands of loci, inbred substrains differ at thousands of loci – only a fraction of which will be functional. These characteristics expedite identification of causal genes in substrains for which phenotypic differences exist. This approach has been used to identify a cocaine-sensitivity gene but has been limited to C57BL/6 substrains. Dozens of inbred substrains exist and opportunities for identifying genes that influence addiction-related behaviors are being missed. We have identified a striking phenotypic difference in cocaine locomotor sensitivity between the C3H substrains, C3H/HeJ and C3H/HeNTac. In this R21 application, we propose to use a RCC to identify the causal allele(s) for the phenotypic differences in these substrains. We will also examine substrain-specific pharmacokinetic and dose response phenotypes and examine the rewarding and reinforcing effects of cocaine using the drug self- administration paradigm. These studies will establish a drug response profile for each C3H substrain and allow us to begin exploring mechanisms by which the causal allele alters behavior.