Faissner A, Kruse J, Chiquet-Ehrismann R, Mackie E
Department of Neurobiology, Heidelberg, Federal Republic of Germany.
Differentiation. 1988;37(2):104-14. doi: 10.1111/j.1432-0436.1988.tb00802.x.
The J1 glycoproteins have been shown to mediate neuron-astrocyte adhesion and appear in the nervous system as four species of Mr 160,000 (J1-160), 180,000 (J1-180), 200,000 (J1-200), and 220,000 (J1-220), respectively. Tenascin is a disulfide-linked oligomeric, extracellular matrix glycoprotein of subunit Mr 170,000, 190,000, 200,000, and 220,000, which has been proposed to promote epithelial cell proliferation. In view of the structural similarities of the molecules we have used immunohistochemical and immunochemical techniques to compare them. Immunohistochemically, polyclonal J1 and tenascin antibodies yielded identical staining patterns in non-nervous-system tissues, and staining could be completely blocked by preincubating the sera with purified tenascin. In the central nervous system all structures expressing tenascin immunoreactivity were also recognized by J1 antibodies. However, not all J1-positive structures were also tenascin-positive, indicating that J1 antibodies recognized additional epitopes not present on tenascin. Western-blot experiments performed with affinity-purified polyclonal J1 antibodies showed that J1 glycoproteins can be subdivided into two separate pairs, J1-160/180 and J1-200/220, which share a small degree of homology. Western-blot experiments and sequential immunoprecipitations on biosynthetically [35S]methionine- or 125I-radiolabeled J1 glycoproteins carried out with polyclonal J1 and tenascin antibodies demonstrated that J1-200/220 is immunochemically indistinguishable from tenascin. These observations suggest that one set of extracellular glycoproteins is associated with processes as different as neural histogenesis and carcinogenesis of mammary glands.
已证明J1糖蛋白介导神经元与星形胶质细胞的黏附，在神经系统中以四种分子量分别为160,000（J1 - 160）、180,000（J1 - 180）、200,000（J1 - 200）和220,000（J1 - 220）的形式出现。腱生蛋白是一种由二硫键连接的寡聚细胞外基质糖蛋白，亚基分子量为170,000、190,000、200,000和220,000，有人提出它可促进上皮细胞增殖。鉴于这些分子的结构相似性，我们使用免疫组织化学和免疫化学技术对它们进行了比较。免疫组织化学方面，多克隆J1和腱生蛋白抗体在非神经系统组织中产生相同的染色模式，并且通过用纯化的腱生蛋白预孵育血清可完全阻断染色。在中枢神经系统中，所有表达腱生蛋白免疫反应性的结构也被J1抗体识别。然而，并非所有J1阳性结构也是腱生蛋白阳性，这表明J1抗体识别了腱生蛋白上不存在的其他表位。用亲和纯化的多克隆J1抗体进行的蛋白质印迹实验表明，J1糖蛋白可分为两个独立的对，即J1 - 160/180和J1 - 200/220，它们具有一定程度的同源性。用多克隆J1和腱生蛋白抗体对生物合成的[35S]甲硫氨酸或125I放射性标记的J1糖蛋白进行蛋白质印迹实验和连续免疫沉淀表明，J1 - 200/220在免疫化学上与腱生蛋白无法区分。这些观察结果表明，一组细胞外糖蛋白与神经组织发生和乳腺肿瘤发生这些不同的过程相关。
