INBORN ERRORS OF A PURINE SALVAGE PATHWAY

嘌呤挽救途径的先天性错误

• 批准号: 3237449
• 负责人: JAY Arnold TISCHFIELD
• 金额: $ 22.61万
• 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/3237449
• 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.

腺嘌呤磷酸核糖转移酶 (APRT) 催化以下反应 腺嘌呤与 5-磷酸核糖基-1-焦磷酸结合产生腺苷 单磷酸盐和焦磷酸盐。 APRT 完全缺乏的情况 在人体中，腺嘌呤被黄嘌呤氧化酶氧化，形成高度 不溶性肾毒性衍生物 2,8-二羟基腺嘌呤 (DHA)。 这 在某些情况下，这种化合物的积累可能会导致生命- 威胁尿石症。 APRT 缺陷是遗传性的 常染色体隐性遗传方式，是一种相对罕见的嘌呤先天性错误 代谢。 然而，大约 1% 的人口是杂合子 亚太时间。 因此，观察到的 APRT 缺陷纯合子要少得多 比预测的杂合子频率。 我们建议： 1. 表征来自其他 APRT 缺陷的突变 APRT 等位基因 患者的 DNA 序列和单倍型。 这样，我们将 研究产生的生殖细胞分子机制（突变） 这种病。 2. 表征 T 细胞体内产生的 APRT 体细胞突变。 因此，我们将确定 T 细胞是否发生突变，这与 比种系突变更容易研究，可以用作模型系统 用于研究种系突变的机制。 体细胞 突变对于理解癌症也很重要。 3. 通过红细胞 APRT 水平降低来识别 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是 与酶缺陷纯合子中观察到的不同。 这 分析可能会揭示这些纯合子的明显缺乏。 4. 制作人类 APRT 缺陷的转基因小鼠模型。 这 该疾病的动物模型将用于基础研究 一般嘌呤的生化机制和生化变化 代谢。 例如，核苷酸库、代谢的处置 将研究腺嘌呤，以及对从头产生嘌呤的影响。 这些动物还将提供常染色体体细胞模型系统 突变将补充人类 T 细胞模型。