Weinstein L S, Gejman P V, de Mazancourt P, American N, Spiegel A M
Molecular Pathophysiology Branch, National Institute of Diabetes, Digestive and Kidney Disease, National Institutes of Health, Bethesda, Maryland 20892.
Genomics. 1992 Aug;13(4):1319-21. doi: 10.1016/0888-7543(92)90056-x.
Several heterozygous mutations within the gene encoding the alpha-subunit of Gs (GNAS1), the G protein that stimulates adenylyl cyclase, have been previously identified in patients with Albright hereditary osteodystrophy (AHO). We have now identified a fourth GNAS1 mutation from an AHO patient. Amplification by the polymerase chain reaction (PCR) of a genomic fragment encompassing GNAS1 exons 7 and 8 from one patient resulted in a product with aberrant migration on nondenaturing polyacrylamide and agarose gels. Direct DNA sequencing identified a 4-bp deletion in one allele of exon 7 encoding a frameshift with a premature stop codon. Analysis of lymphocyte RNA by reverse transcription-PCR and direct sequencing showed that the GNAS1 allele bearing the mutation is not expressed as mRNA. Consistent with this, Northern analysis revealed an approximate 50% deficiency in steady-state levels of GNAS1 mRNA. These findings further illustrate the heterogeneity of GNAS1 gene defects in AHO.
在患有奥尔布赖特遗传性骨营养不良（AHO）的患者中，先前已鉴定出编码刺激腺苷酸环化酶的G蛋白Gs（GNAS1）α亚基的基因内的几种杂合突变。我们现在从一名AHO患者中鉴定出第四个GNAS1突变。通过聚合酶链反应（PCR）扩增一名患者包含GNAS1外显子7和8的基因组片段，在非变性聚丙烯酰胺和琼脂糖凝胶上产生了迁移异常的产物。直接DNA测序在编码移码且带有提前终止密码子的外显子7的一个等位基因中鉴定出一个4bp的缺失。通过逆转录PCR和直接测序对淋巴细胞RNA进行分析表明，携带该突变的GNAS1等位基因未作为mRNA表达。与此一致的是，Northern分析显示GNAS1 mRNA的稳态水平大约有50%的缺陷。这些发现进一步说明了AHO中GNAS1基因缺陷的异质性。
