Swaroop A, Hogan B L, Francke U
Department of Human Genetics, Yale University School of Medicine, New Haven, Connecticut 06510.
Genomics. 1988 Jan;2(1):37-47. doi: 10.1016/0888-7543(88)90107-3.
Human cDNA clones encoding the extracellular calcium-binding, acidic glycoprotein known as SPARC, osteonectin, or BM-40 were isolated from a placental cDNA library. Two polyadenylated transcripts of 2.2 and 3.0 kb were detected in human tissues and cultured cells by Northern blot analysis, and cDNAs for both transcripts were characterized. The 2133-bp sequence of the more abundant (major) transcript contains an open reading frame for 303 amino acids. The deduced polypeptide has extensive amino acid sequence identity with mouse SPARC. The larger and minor 3.0-kb cDNA has an identical coding region but utilizes a downstream polyadenylation signal. Gene localization studies have revealed a single chromosomal site at 5q31-q33 by somatic cell hybrid analysis and in situ chromosomal hybridization. Furthermore, pulsed-field gel electrophoresis of human genomic DNA cleaved with different rare-cutting restriction enzymes and hybridized with SPARC cDNA probes revealed single or double fragments of less than 50 to about 150 kb. The evidence is consistent with a single locus for SPARC in humans. The gene was found to be differentially expressed in many human tissues and in an osteogenic sarcoma, but not in other transformed cells.
从胎盘cDNA文库中分离出编码细胞外钙结合酸性糖蛋白（称为SPARC、骨连接蛋白或BM-40）的人cDNA克隆。通过Northern印迹分析在人体组织和培养细胞中检测到2.2 kb和3.0 kb的两种多聚腺苷酸化转录本，并对这两种转录本的cDNA进行了表征。较丰富（主要）转录本的2133 bp序列包含一个303个氨基酸的开放阅读框。推导的多肽与小鼠SPARC具有广泛的氨基酸序列同一性。较大的3.0 kb次要cDNA具有相同的编码区，但利用了下游的多聚腺苷酸化信号。基因定位研究通过体细胞杂交分析和原位染色体杂交揭示了5q31-q33的单个染色体位点。此外，用不同的稀有切割限制酶切割并与SPARC cDNA探针杂交的人基因组DNA的脉冲场凝胶电泳显示出小于50至约150 kb的单片段或双片段。证据表明SPARC在人类中为单一位点。发现该基因在许多人体组织和成骨肉瘤中差异表达，但在其他转化细胞中不表达。
