Furley A J, Morton S B, Manalo D, Karagogeos D, Dodd J, Jessell T M
Department of Biochemistry and Molecular Biophysics, New York, New York.
Cell. 1990 Apr 6;61(1):157-70. doi: 10.1016/0092-8674(90)90223-2.
Pathfinding of axons in the developing nervous system is thought to be mediated by glycoproteins expressed on the surface of embryonic axons and growth cones. One molecule suggested to play a role in axonal growth is TAG-1, a 135 kd glycoprotein expressed transiently on the surface of subsets of neurons in the developing mammalian nervous system. We isolated a full-length cDNA clone encoding rat TAG-1. TAG-1 has six immunoglobulin-like domains and four fibronectin type III-like repeats and is structurally similar to other immunoglobulin-like proteins expressed on developing axons. Neurons maintained in vitro on a substrate of TAG-1 extend long neurites, suggesting that this protein plays a role in the initial growth and guidance of axons in vivo. TAG-1 is anchored to the neuronal membrane via a glycosyl phosphatidylinositol linkage and is also released from neurons, suggesting that TAG-1 also functions as a substrate adhesion molecule when released into the extracellular environment.
在发育中的神经系统中，轴突的路径寻找被认为是由胚胎轴突和生长锥表面表达的糖蛋白介导的。一种被认为在轴突生长中起作用的分子是TAG-1，它是一种135kd的糖蛋白，在发育中的哺乳动物神经系统的神经元亚群表面短暂表达。我们分离出了一个编码大鼠TAG-1的全长cDNA克隆。TAG-1有六个免疫球蛋白样结构域和四个纤连蛋白III型重复序列，在结构上与发育中的轴突上表达的其他免疫球蛋白样蛋白相似。在TAG-1底物上体外培养的神经元会伸出长长的神经突，这表明该蛋白在体内轴突的初始生长和导向中起作用。TAG-1通过糖基磷脂酰肌醇连接锚定在神经元膜上，并且也从神经元中释放出来，这表明TAG-1在释放到细胞外环境中时也作为一种底物粘附分子发挥作用。
