Genetic Complexity and Modifiers of Hirschsprung Disease

先天性巨结肠症的遗传复杂性和修饰因素

• 批准号: 6625729
• 负责人: E Michelle SOUTHARD-SMITH
• 金额: $ 34.42万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6625729
• 关键词: autonomic ganglion; congenital megacolon; developmental neurobiology; embryogenesis; gastrointestinal motility /pressure; gene interaction; genetic mapping; genetic polymorphism; genetic strain; genetic susceptibility; laboratory mouse; mammalian embryology; neurogenetics; neuroregulation

DESCRIPTION (provided by applicant): Hirschsprung disease (HSCR) is a complex genetic disorder that gives rise to absence of intrinsic ganglia in the distal intestine and consequently produces gastrointestinal dysmotility. Mutations in any one of several genes can give rise to the intestinal aganglionosis that is the hallmark of this disease. Incomplete penetrance and variable expressivity of the neural crest (NC) defects exhibited by family members carrying identical gene mutations suggests that multiple genes modulate HSCR severity. Mouse models of HSCR have been extremely valuable for identifying genes that participate in pathogenesis of enteric nervous system (ENS) defects. Genetic and embryonic analysis of the mouse mutant Sox10Dom has defined a role for this transcription factor in development of the ENS. Our analysis of Sox10Dom mice in F1 hybrid and inbred strains demonstrates that genetic background impacts severity of intestinal aganglionosis. The phenotypic variation we observe mimics that seen in human HSCR sibs and suggests that modifier loci influence development of Sox10 derivatives in mouse and man. In the proposed experiments we will test the hypothesis that gene interactions between loci impact ENS development. Congenic lines of Sox10Dom mice will be used to define the timing and effect of genetic background on the enteric NC. Specifically we will evaluate survival, proliferation, and migration of enteric NC in embryos from Sox10Dom congenic lines. To identify the genes responsible for the phenotypic variation in the Sox10Dom HSCR model we will evaluate association between alleles at candidate modifier loci and severity of intestinal aganglionosis in Sox10Dom animals maintained on an F1 hybrid background. Potential gene interactions will be validated in vivo by examining severity of aganglionosis in crosses between Sox10Dom and mutants at candidate modifier loci. Our preliminary analysis has already identified a highly significant interaction between Sox10 and EdnrB and we have identified Sox10 consensus binding sites in EdnrB flanking regions. To investigate the biological interaction between Sox10 and EdnrB we will identify sequence variants at the EdnrB locus. The functional effects of polymorphisms on levels of EdnrB mRNA and function will be evaluated in neural tube (NT) and enteric ganglia cultures from our congenic lines. These experiments are part of a unified strategy to define the mechanisms of gene interaction that participate in development and pathogenesis of the ENS.

描述（由申请人提供）：先天性巨结肠症 (HSCR) 是一种复杂的疾病 导致远端固有神经节缺失的遗传性疾病 肠，从而产生胃肠道运动障碍。突变在 几种基因中的任何一种都可以引起肠道无神经节细胞病，即 这种疾病的特征。不完全外显率和可变表达率 携带相同基因的家庭成员表现出的神经嵴（NC）缺陷 基因突变表明多个基因调节 HSCR 的严重程度。老鼠 HSCR 模型对于识别基因非常有价值 参与肠神经系统（ENS）缺陷的发病机制。遗传 小鼠突变体 Sox10Dom 的胚胎分析确定了其作用 ENS 发育中的转录因子。我们对 Sox10Dom 小鼠的分析 F1 杂交和近交系表明遗传背景影响 肠无神经节病的严重程度。我们观察到的表型变异 模仿在人类 HSCR 同胞中看到的情况，并表明修饰基因座影响 在小鼠和人类中开发 Sox10 衍生物。在提议的实验中 我们将检验基因座之间的基因相互作用影响 ENS 的假设 发展。 Sox10Dom 小鼠的同类系将用于定义时间 以及遗传背景对肠道NC的影响。具体我们将 评估胚胎中肠道 NC 的存活、增殖和迁移 Sox10Dom 同类系。鉴定负责表型的基因 Sox10Dom HSCR 模型的变化，我们将评估之间的关联 候选修饰位点的等位基因和肠道无神经节细胞病的严重程度 Sox10Dom 动物维持在 F1 杂交背景上。潜力基因 通过检查神经节缺失的严重程度，将在体内验证相互作用 Sox10Dom 与候选修饰基因座突变体之间的杂交。我们的 初步分析已经确定了非常重要的相互作用 Sox10 和 EdnrB 之间，我们已经确定了 Sox10 共有结合位点 EdnrB 侧翼区域。研究 Sox10 之间的生物相互作用 和 EdnrB，我们将鉴定 EdnrB 基因座的序列变异。功能性的 将评估多态性对 EdnrB mRNA 水平和功能的影响 在来自我们同类系的神经管（NT）和肠神经节培养物中。这些 实验是定义基因机制的统一策略的一部分 参与 ENS 发育和发病机制的相互作用。