INBORN ERRORS OF A PURINE SALVAGE PATHWAY

嘌呤挽救途径的先天性错误

• 批准号: 3237450
• 负责人: JAY Arnold TISCHFIELD
• 金额: $ 9.19万
• 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 1991-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3237450
• 关键词: adenine; adenine phosphoribosyltransferase; antiserum; biological polymorphism; cell transformation; clone cells; epidemiology; gel electrophoresis; gene expression; human tissue; inborn metabolism disorder; messenger RNA; molecular cloning; molecular genetics; nucleic acid sequence; pancreatic ribonuclease; purine /pyrimidine metabolism disorder

Adenine phosphoribosyltransferase (APRT), an enzyme of purine salvage, utilizes adenine and 5-phosphoribosyl-1-pyrophosphate to produce adenosine monophosphate and pyrophosphate. In man, complete APRT deficiency is a supposedly rare inborn error of purine metabolism that is inherited in an autosomal recessive manner. Adenine, which is primarily a byproduct of polyamine biosynthesis, accumulates to high levels in APRT deficient individuals and is ultimately oxidized to 2,8-dihydrixyadenine (DHA). Although the defect can be relatively benign, DHA is nephrotoxic and can lead to life-threatening DHA urolithiasis. A relatively high frequency of apparent heterozygosity for this disorder suggests that homozygosity could be more frequent than is currently recognized, presumably due to highly variable clinical expression coupled with problems of diagnosis. We have cloned a functional human APRT gene and have determined the nucleotide sequence of its coding regions and introns. We also have cell cultures from APRT deficient patients and APRT deficient human cell clones obtained by selection from normal somatic cells in vitro. Using our cloned gene to probe these cells, we will determine the molecular bases for expression of human APRT deficiency. By comparing mutant APRT genes in the human population to those obtained from cultured, human somatic cells we will ascertain whether or not somatic cell mutation in vitro, which forms the basis of most mutagenesis assays, is qualitatively different from mutation in germ cells in situ. Mutant cell nucleic acids will be analyzed by Southern and northern blots, RNase A digestion of DNA/RNA molecular hybrids and DNA sequence analysis. Mutant APRT proteins will also be analyzed using antisera directed against the N or C-termini of the normal enzyme.

腺嘌呤磷酸核糖转移酶（APRT）是一种嘌呤回收酶，