da Veiga Pereira L, Desnick R J, Adler D A, Disteche C M, Schuchman E H
Division of Medical and Molecular Genetics, Mount Sinai School of Medicine, New York, New York 10029.
Genomics. 1991 Feb;9(2):229-34. doi: 10.1016/0888-7543(91)90246-b.
Human acid sphingomyelinase (SMPD1) is the lysosomal phosphodiesterase that cleaves sphingomyelin to ceramide and phosphocholine. The deficient activity of SMPD1 is the enzymatic defect in Types A and B Niemann-Pick disease. Previously, the gene encoding human SMPD1 was assigned to chromosome 17 by the differential thermostability of human and hamster SMPD1 in somatic cell hybrids. The recent isolation of the human SMPD1 cDNA (L. E. Quintern, E. H. Schuchman, O. Levran, M. Suchi, K. Ferlinz, H. Reinke, K. Sandhoff, and R. J. Desnick, 1989, EMBO J. 8: 2469-2473) permitted the mapping of this gene by molecular techniques. Oligonucleotide primers were synthesized to PCR amplify the human, but not murine, SMPD1 sequences in man-mouse somatic cell hybrids. In a panel of 15 hybrid cell lines, amplification of the human SMPD1 sequence was 100% concordant with the presence of human chromosome 11. For each of the other human chromosomes there were at least 6 discordant hybrid lines. Further analysis of somatic cell hybrids containing only chromosome 11 or chromosome 11 rearrangements localized the human SMPD1 gene to the region 11p15.1----p15.4. To provide an independent regional gene assignment, in situ hybridization was performed using the radiolabeled human SMPD1 cDNA. In the 58 metaphase cells examined, 34% of the 122 hybridization sites scored were located in the distal end of chromosome 11 with the major peak of hybridization at band 11p15. The absence of any other in situ hybridization site indicated the absence of pseudogenes or homologous sequences elsewhere in the genome. In contrast to the previous provisional localization to chromosome 17, these results assign a single locus for human SMPD1 to 11p15.1----p15.4.
人酸性鞘磷脂酶（SMPD1）是一种溶酶体磷酸二酯酶，可将鞘磷脂裂解为神经酰胺和磷酸胆碱。SMPD1活性缺乏是A型和B型尼曼-匹克病的酶缺陷。此前，通过人鼠体细胞杂种中人SMPD1和仓鼠SMPD1的热稳定性差异，将编码人SMPD1的基因定位于17号染色体。最近人SMPD1 cDNA的分离（L.E. 昆特恩、E.H. 舒克曼、O. 莱夫兰、M. 苏奇、K. 费林兹、H. 赖内克、K. 桑德霍夫和R.J. 德斯尼克，1989年，《欧洲分子生物学组织杂志》8：2469 - 2473）使得能够通过分子技术对该基因进行定位。合成了寡核苷酸引物，用于在人鼠体细胞杂种中通过PCR扩增人而非鼠的SMPD1序列。在一组15个杂种细胞系中，人SMPD1序列的扩增与11号人类染色体的存在100%一致。对于其他每条人类染色体，至少有6个不一致的杂种细胞系。对仅含11号染色体或11号染色体重排的体细胞杂种进行进一步分析，将人SMPD1基因定位于11p15.1----p15.4区域。为了提供独立的区域基因定位，使用放射性标记的人SMPD1 cDNA进行了原位杂交。在所检查的58个中期细胞中，122个杂交位点中有34%位于11号染色体的远端，杂交主峰位于11p15带。未发现任何其他原位杂交位点，表明基因组其他位置不存在假基因或同源序列。与先前暂定定位于17号染色体不同，这些结果将人SMPD1的单一基因座定位于11p15.1----p15.4。
