INBORN ERRORS OF A PURINE SALVAGE PATHWAY

嘌呤挽救途径的先天性错误

• 批准号: 2140313
• 负责人: JAY Arnold TISCHFIELD
• 金额: $ 22.98万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2140313
• 关键词: CHO cells; adenine; clone cells; cytotoxicity; embryonic stem cell; enzyme activity; enzyme deficiency; family genetics; gene mutation; genetic mapping; genetically modified animals; human tissue; inborn metabolism disorder; laboratory mouse; molecular cloning; molecular pathology; nucleic acid sequence; purine /pyrimidine metabolism disorder; urinalysis; urinary calculi

Adenine phosphoribosyltransferase (APRT) catalyzes the reaction of adenine with 5-phosphoribosyl-1-pyrophosphate that produces adenosine monophosphate and pyrophosphate. In cases of complete APRT deficiency in man, adenine is oxidized by xanthine oxidase to form the highly insoluble and nephrotoxic derivative, 2,8-dihydroxyadenine (DHA). The accumulation of this compound may, in some instances, lead to life- threatening urolithiasis. APRT deficiency, which is inherited in an autosomal recessive manner, is a relatively rare inborn error of purine metabolism. However, about 1% of the population is heterozygous at APRT. Thus, far fewer APRT-deficient homozygotes have been observed than the frequency of heterozygotes would predict. We propose to: 1. Characterize mutant APRT alleles from additional APRT-deficient patients with regard to their DNA sequence and haplotype. Thus, we will investigate germline cell molecular mechanisms (mutations) that produce this disease. 2. Characterize APRT somatic mutations arising in vivo in T cells. Thus, we will determine whether or not T cell mutation, which is far easier to study than germline mutation, can be used as a model system for investigating mechanisms of germline mutagenesis. Somatic cell mutation is also important for understanding cancer. 3. Identify APRT heterozygotes by their reduced levels of red cell APRT activity and sequence their mutant alleles. Thus, we will determine whether or not the spectrum of mutant alleles in heterozygotes is different from that observed in enzyme-deficient homozygotes. This analysis may shed light on the apparent paucity of these homozygotes. 4. Produce a transgenic mouse model for human APRT deficiency. This animal model for the disease will be used for studies of underlying biochemical mechanisms and biochemical changes in general purine metabolism. For example, nucleotide pools, the disposition of metabolic adenine, and effects on de novo purine production will be studied. These animals will also provide a model system for autosomal somatic mutation that will complement the human T cell model.

腺嘌呤磷酸核糖基转移酶（APRT）催化 腺嘌呤与5-磷酸核糖基-1-焦磷酸形成腺苷 单磷酸盐和焦磷酸盐。 在APRT完全缺乏的情况下 在人体内，腺嘌呤被黄嘌呤氧化酶氧化，形成高度 不溶性和肾毒性衍生物，2，8-二羟基腺嘌呤（DHA）。 的 在某些情况下，这种化合物的积累可能会导致生命的产生， 威胁尿石症 APRT缺陷，这是遗传在一个 常染色体隐性方式，是一种比较少见的先天性嘌呤错误 新陈代谢. 然而，大约1%的人群是杂合子， APRT。 因此，很少有APRT缺陷纯合子被观察到 比杂合子的频率更高 我们建议： 1. 表征来自其他APRT缺陷型的突变APRT等位基因 患者的DNA序列和单倍型。 因此，我们将 研究生殖细胞分子机制（突变）， 这种疾病。 2. 表征T细胞中体内产生的APRT体细胞突变。 因此，我们将确定是否T细胞突变，这是远远不够的， 比生殖系突变更容易研究，可用作模型系统 用于研究生殖系突变的机制。 体细胞 突变对于理解癌症也很重要。 3. 通过红细胞APRT水平降低识别APRT杂合子 活性并对其突变等位基因进行测序。 因此，我们将确定 杂合子中突变等位基因的谱是否 不同于在酶缺陷纯合子中观察到的。 这 分析可能揭示这些纯合子的明显缺乏。 4. 建立人APRT缺陷的转基因小鼠模型。 这 该疾病的动物模型将用于研究潜在的 普通嘌呤的生化机制和生化变化 新陈代谢. 例如，核苷酸库，代谢产物的分布， 腺嘌呤，并将研究对从头嘌呤产生的影响。 这些动物也将为常染色体体细胞遗传学研究提供模型系统。 突变，这将补充人类T细胞模型。