GENETIC STUDY OF A CHILDHOOD DISEASE AFFECTNG INTRACELLULAR CHOLESTEROL TRANSPORT

基本的Decectin C型尼曼-皮克病是未知的。作为分离C型Niemann-Pick病基因缺陷的尝试，我们建立了一个永生化的C型鞘磷脂病小鼠3T3细胞系，发现这些细胞表现出与C型Niemann-Pick病患者成纤维细胞相同的异常炎症。在研究C型Niemann-Pick病的胆固醇酯代谢的过程中，我们发现患者的成纤维细胞具有增加胆固醇生物合成的新途径。当细胞Ara暴露于胆固醇生物合成抑制剂时，它们表现出异常的敏感性。它们对维生素D3的细胞毒作用表现出明显的超敏反应。该药物可用于丰富和分离转染人正常c DNA或基因组DNA后恢复胆固醇代谢的少数细胞。此外，通过将人染色体从鞘磷脂病小鼠体内转移到3T3细胞系，我们发现了一个恢复胆固醇代谢的人18号染色体。经Southern分析，该基因座位于染色体远端。这些结果表明，C型尼曼-匹克病的缺陷基因可以通过利用小鼠细胞系和可选药物的表达克隆或通过定位克隆来分离

Basic defectin type C Niemann-Pick disease is unknown. As an attempt to isolate the gene defectivein type C Niemann-Pick Disease, we have established an immortalized 3T3 cell line from sphingomelinosis mouse and found the cells show the same abnormalitis found in fibroblasts from patients with type C Niemann-Pick disease. In course of studies to characterizecholesterol metabolism in type C Niemann-Pick disease, we have fund fibroblasts from the patients have an increasedde novo pathway of cholesterol biosynthesis. When cells ara exposed to cholesterol biosynthetic inhibitors, they showed abnormal sensitivities. They showed marked hypersensitivity to cytotoxic effect of vitamin D3. The drug should be very useful to enrich and isolate a few cells restored cholesterol metabolism after transfecting human normal cDNA or genomic DNA.In addition, by transfer of a human chromosome into 3T3 cell line from sphingomyelinosis mouse, we have found a human chromosome 18 restore the cholesterol metabolism. BY Southern analysis, the gene locus is assigned to distal portion of the chromosome. These results suggest that the gene defective in type C Niemann-Pick disease could be isolated by expresstion cloning using the mouse cell line and the selectable drug or by positional cloning