Geraghty M T, Vaughn D, Nicholson A J, Lin W W, Jimenez-Sanchez G, Obie C, Flynn M P, Valle D, Hu C A
Institute for Genetic Medicine, Department of Pediatrics, Predoctoral Training Program in Human Genetics and Molecular Biology and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Hum Mol Genet. 1998 Sep;7(9):1411-5. doi: 10.1093/hmg/7.9.1411.
We surveyed Delta1-pyrroline 5-carboxylate dehydrogenase genes from four patients with hyperprolinemia type II using RT-PCR amplification, genomic PCR amplification and direct sequencing. We found four mutant alleles, two with frameshift mutations [A7fs(-1) and G521fs(+1)] and two with missense mutations (S352L and P16L). To test the functional consequences of three of these, we expressed them in a P5CDh-deficient strain of Saccharomyces cerevisiae . In contrast to wild-type human P5CDh, yeast expressing S352L and G521fs(+1) failed to grow on proline and had no detectable P5CDh activity. The P16L allele, however, produced fully functional P5CDh and subsequent analysis suggests that it is polymorphic in the relevant (Spanish) population. Interestingly, the G521fs(+1) allele segregates in the large Irish Traveller pedigree used to define the HPII phenotype. To our knowledge, this is the first description of the molecular basis for this inborn error.
我们使用逆转录聚合酶链反应（RT-PCR）扩增、基因组聚合酶链反应（PCR）扩增和直接测序技术，对4名II型高脯氨酸血症患者的Δ1-吡咯啉5-羧酸脱氢酶基因进行了检测。我们发现了4个突变等位基因，其中2个为移码突变[A7fs(-1)和G521fs(+1)]，2个为错义突变（S352L和P16L）。为了测试其中3个突变的功能后果，我们将它们在酿酒酵母的P5CDh缺陷菌株中进行表达。与野生型人类P5CDh不同，表达S352L和G521fs(+1)的酵母无法在脯氨酸上生长，且未检测到P5CDh活性。然而，P16L等位基因产生了完全功能性的P5CDh，后续分析表明它在相关（西班牙）人群中是多态性的。有趣的是，G521fs(+1)等位基因在用于定义HPII表型的大型爱尔兰游民家系中呈分离状态。据我们所知，这是对这种先天性疾病分子基础的首次描述。
