DEVELOPMENT OF A MODEL OF GLUTARIC ACIDEMIA

谷氨酸血症（GA-I）是一种遗传性氨基酸代谢紊乱 其临床特征为锥体外系运动障碍， 在儿童期和病理学上由尾状核中的神经元损失和胶质增生引起 和壳核。GA-I是由戊二酰辅酶A缺乏引起的 脱氢酶（GCDH），是少数运动障碍之一，其遗传 根据已知。 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、鼠和猪GCDH蛋白的克隆 cDNA。目前正在开展工作，以评估特定的表型效应， GA-I患者的人类基因突变。 作为进一步了解病理生理机制的一种手段， 参与了特征性神经解剖学的发展， GA-I的临床特征，我们建议产生这种小鼠模型， 疾病利用最近克隆的小鼠cDNA，我们现在正在克隆 鼠GCDH基因，用于制备靶向载体， 在胚胎干（ES）细胞中产生无效GCDH等位基因， 重组这些突变的胚胎干细胞将被用来产生一个细胞系 突变GCDH等位基因的杂合子小鼠。随后，委员会决定， 这些杂合子动物将用于评价发育 使用标记基因表达GCDH，所述标记基因被掺入GCDH中。 目标载体这样的分析将考虑到 GCDH的表达模式具有非常特征性的神经病理学。 杂合动物也将进行杂交以产生动物 GCDH等位基因的纯合子。纯合子动物将经历 广泛的生化、行为和神经化学评估， 确定它们是否是GA-I的良好模型。如果事实上他们是一个 GA-I模型，这些动物可用于检验特定假设 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.