Tomatsu S, Sukegawa K, Ikedo Y, Fukuda S, Yamada Y, Sasaki T, Okamoto H, Kuwabara T, Orii T
Department of Pediatrics, Gifu University, School of Medicine, Japan.
Gene. 1990 May 14;89(2):283-7. doi: 10.1016/0378-1119(90)90019-n.
We have identified a mutation causing beta-glucuronidase (beta Gl) deficiency in a 6-year-old girl with mucopolysaccharidosis type VII. Enzyme assay of lysates of a girl's lymphocytes or cultured fibroblasts showed little residual activity and a normal beta Gl-specific mRNA level, as revealed by Northern-blot analysis. Sequencing of the full-length mutated cDNA revealed a C----T transition, an event causing a single Ala619----Val change (we designated this variant beta GGifu). This change is detected by loss of the cleavage site for the enzyme Fnu4HI in the mutated cDNA. On the basis of the loss of Fnu4HI restriction site, the patient was shown to be a homozygote with the beta GGifu mutation and her parents and brother were heterozygotes. This mutation disrupts a functional domain consisting of a region of sequence highly conserved among human, rat and bacterial beta Gls, and it reduces the enzyme activity, as tested by transfection of COS cells with expression vectors harboring the mutated cDNA.
我们在一名患有VII型黏多糖贮积症的6岁女孩中发现了一种导致β-葡萄糖醛酸酶（βGl）缺乏的突变。对该女孩淋巴细胞或培养的成纤维细胞裂解物进行的酶活性测定显示，残留活性很低，而Northern印迹分析显示βGl特异性mRNA水平正常。全长突变cDNA测序显示发生了C→T转换，该事件导致单个Ala619→Val改变（我们将此变体命名为βGGifu）。在突变的cDNA中，通过酶Fnu4HI切割位点的缺失检测到了这种变化。基于Fnu4HI限制位点的缺失，该患者被证明是βGGifu突变的纯合子，其父母和兄弟为杂合子。通过用携带突变cDNA的表达载体转染COS细胞进行测试，该突变破坏了一个由人、大鼠和细菌βGl中高度保守的序列区域组成的功能域，并降低了酶活性。
