Ge A Z, Butcher E C
Department of Pathology, Stanford University School of Medicine, CA 94305.
Gene. 1994 Jan 28;138(1-2):201-6. doi: 10.1016/0378-1119(94)90808-7.
The rat monoclonal antibody, MJ7/18, which reacts selectively with the endothelium of blood vessels in mouse was used to screen a cDNA library derived from a transformed mouse brain endothelial cell line. The sequence of a cDNA encoding the cell surface MJ7/18 antigen revealed homology to human endoglin, a homodimeric transforming growth factor-beta (TGF-beta)-binding cell-surface glycoprotein expressed predominantly on vascular endothelial cells. Northern blot analysis shows a 3.4-kb single transcript of the mouse endoglin. The mouse endoglin is a type-I integral membrane protein of 653 amino acids (aa). The human and mouse sequences display 71% aa sequence identity with almost identical transmembrane and cytoplasmic domains. Like its human counterpart, mouse endoglin displays significant sequence homology to the type-III TGF-beta receptor in two extracellular domains, as well as striking similarity in the transmembrane and cytoplasmic regions. One of the extracellular regions of homology with TGF-beta receptor III represents a truncated version of a homology unit defining a novel gene family including uromodulin, the pancreatic granule protein gp2, and zona pellucida receptors for sperm. However, unlike its human counterpart, mouse endoglin does not contain an RGD tripeptide which has been suggested as a ligand of integrins.
大鼠单克隆抗体MJ7/18能与小鼠血管内皮细胞发生特异性反应，用其筛选来自转化小鼠脑内皮细胞系的cDNA文库。编码细胞表面MJ7/18抗原的cDNA序列显示与人内皮糖蛋白具有同源性，内皮糖蛋白是一种同二聚体转化生长因子-β（TGF-β）结合细胞表面糖蛋白，主要表达于血管内皮细胞。Northern印迹分析显示小鼠内皮糖蛋白有一条3.4kb的单转录本。小鼠内皮糖蛋白是一种含653个氨基酸（aa）的I型整合膜蛋白。人和小鼠序列显示71%的氨基酸序列同一性，其跨膜和胞质结构域几乎相同。与人类内皮糖蛋白一样，小鼠内皮糖蛋白在两个细胞外结构域与III型TGF-β受体显示出显著的序列同源性，在跨膜和胞质区域也有惊人的相似性。与TGF-β受体III同源的一个细胞外区域代表一个同源单位的截短形式，该同源单位定义了一个新的基因家族，包括尿调节蛋白、胰腺颗粒蛋白gp2和精子透明带受体。然而，与人类内皮糖蛋白不同，小鼠内皮糖蛋白不包含已被认为是整合素配体的RGD三肽。
