DEVELOPMENT OF A MODEL OF GLUTARIC ACIDEMIA

戊二酸血症是一种遗传性氨基酸代谢紊乱 临床特征为锥体外系运动障碍 儿童时期和病理上尾状核神经元丢失和胶质细胞增生 还有贝壳。GA-I是由戊二酰辅酶A缺乏引起的 脱氢酶(GCDH)是少数几种遗传性运动障碍之一 根据是已知的。在过去的几年里，我们中心的工作导致了 GCDH蛋白的分离及人、鼠、猪的克隆 CDNA。正在进行评估特定基因的表型效应的工作 GA-I患者的人类基因突变。 作为进一步了解其病理生理机制的一种手段 参与了特有的神经解剖学和 GA-I的临床特征我们建议建立一个这样的小鼠模型 疾病。使用最近克隆的小鼠cdna，我们现在正在克隆 小鼠GCDH基因为构建靶向载体做准备 通过同源基因在胚胎干细胞中产生零GCDH等位基因 重组。这些突变的ES细胞将被用来产生一条线 突变的GCDH等位基因杂合子的小鼠。后来， 这些杂合子动物将被用来评估发育 利用标记基因表达GCDH，并将其整合到 目标向量。这样的分析将允许将 GCDH的表达模式具有非常特征性的神经病理。 杂合子动物也将被杂交以产生动物。 GCDH缺失型等位基因纯合。纯合的动物将经历 广泛的生化、行为和神经化学评估，以便 确定它们是否是GA-I的良好模型。如果他们实际上是一个 GA-I模型，这些动物可以用来检验特定的假设 关于病理生理学和对各种治疗方式的反应。

Glutaric acidemia (GA-I) is an inherited disorder of amino acid metabolism that is characterized clinically by an extrapyramidal movement disorder in childhood and pathologically by neuronal loss and gliosis in the caudate and putamen. GA-I is caused by a deficiency of the enzyme glutaryl CoA dehydrogenase (GCDH) and is one of few movement disorders whose genetic basis is known. Over the past several years work in our center has led to the isolation of the GCDH protein and cloning of human, murine and porcine cDNAs. Work is ongoing to evaluate the phenotypic effects of specific mutations in the human gene in patients with GA-I. As a means to further the understanding of the pathophysiologic mechanisms involved in the development of the characteristic neuroanatomic and clinical features of GA-I we propose to generate a mouse model of this disease. Using the recently cloned murine cDNA we are now cloning the murine GCDH gene in preparation for creating a targeting vector to generate a null GCDH allele in embryonic stem (ES) cells via homologous recombination. These mutated ES cells will then be used to generate a line of mice that is heterozygous for the mutated GCDH allele. Subsequently, these heterozygous animals will be used to evaluate the developmental expression of GCDH using a marker gene which is incorporated into the targeting vector. Such analysis will allow for a correlation of the expression pattern of GCDH with the very characteristic neuropathology. The heterozygous animals will also be crossed to generate animals homozygous for the null GCDH allele. The homozygous animals will undergo extensive biochemical, behavioral and neurochemical evaluation in order to determine whether they are a good model of GA-I. If in fact they are a model of GA-I, these animals can be used to test specific hypothesis regarding pathophysiology and response to various treatment modalities.