Shelly L L, Lei K J, Pan C J, Sakata S F, Ruppert S, Schutz G, Chou J Y
Human Genetics Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
J Biol Chem. 1993 Oct 15;268(29):21482-5.
Glycogen storage disease (GSD) type 1a (von Gierke disease) is caused by a deficiency in glucose-6-phosphatase, the key enzyme in glucose homeostasis catalyzing the terminal step in gluconeogenesis and glycogenolysis. Despite its clinical importance, this membrane-bound enzyme has eluded molecular characterization. Here we report the cloning and characterization of a murine glucose-6-phosphatase cDNA by screening a mouse liver cDNA library differentially with mRNA populations representing the normal and the albino deletion mouse known to express markedly reduced glucose-6-phosphatase activity. Additionally, we identified the gene that consists of 5 exons. Biochemical analyses indicate that the in vitro expressed enzyme is indistinguishable from mouse liver microsomal glucose-6-phosphatase exhibiting essentially identical kinetic constants, latency, thermal lability, and vanadate sensitivity. The characterization of the murine glucose-6-phosphatase gene opens the way for studying the molecular basis of GSD type 1a in humans and its etiology in an animal model.
1a型糖原贮积病（冯·吉尔克病）是由葡萄糖-6-磷酸酶缺乏引起的，该酶是葡萄糖稳态中的关键酶，催化糖异生和糖原分解的最后一步。尽管其具有临床重要性，但这种膜结合酶的分子特征一直未被阐明。在此，我们通过用代表正常和已知葡萄糖-6-磷酸酶活性显著降低的白化缺失小鼠的mRNA群体差异筛选小鼠肝脏cDNA文库，报告了小鼠葡萄糖-6-磷酸酶cDNA的克隆和特征。此外，我们鉴定了由5个外显子组成的基因。生化分析表明，体外表达的酶与小鼠肝脏微粒体葡萄糖-6-磷酸酶无差异，表现出基本相同的动力学常数、潜伏性、热不稳定性和钒酸盐敏感性。小鼠葡萄糖-6-磷酸酶基因的特征为研究人类1a型糖原贮积病的分子基础及其在动物模型中的病因学开辟了道路。
