Eckenstein F P, Esch F, Holbert T, Blacher R W, Nishi R
Department of Cell Biology and Anatomy, Oregon Health Sciences University, Portland 97201.
Neuron. 1990 Apr;4(4):623-31. doi: 10.1016/0896-6273(90)90120-5.
The validation of NGF as a physiologically important neurotrophic factor has led to intense efforts to identify novel polypeptide growth factors for neurons. We report here the details of a greater than 80,000-fold purification of a neurotrophic molecule, referred to as growth-promoting activity (GPA), from chicken sciatic nerves. The final product of the purification migrated as a protein band of 21.5 kd, its apparent pI was approximately 4.8, and the ED50 of the most active preparation was approximately 10 pg/ml. Amino acid sequence of a proteolytic digestion fragment of GPA revealed homology with the recently published sequences for rabbit and rat sciatic nerve CNTF. Thus this molecule may be the chicken form of CNTF. Analysis of the specificity of action of GPA showed that, in addition to E8 ciliary ganglion neurons, the factor was able to support short-term survival of E8 dorsal root ganglion and E12 sympathetic neurons. This range of specificities of biological action was also seen with both acidic and basic FGF in the presence of heparin. The biological activity of GPA differed from that of FGF in that it was not potentiated by heparin and did not stimulate mitogenesis in chick fibroblasts.
神经生长因子（NGF）作为一种具有重要生理意义的神经营养因子得到验证后，人们便开始大力寻找新的神经元多肽生长因子。我们在此报告从鸡坐骨神经中纯化一种神经营养分子（称为生长促进活性因子，GPA）的详细过程，该分子的纯化倍数超过80000倍。纯化的最终产物迁移为一条21.5kd的蛋白带，其表观pI约为4.8，活性最强的制剂的半数有效剂量（ED50）约为10pg/ml。GPA蛋白水解消化片段的氨基酸序列与最近发表的兔和大鼠坐骨神经睫状神经营养因子（CNTF）序列具有同源性。因此，该分子可能是鸡源形式的CNTF。对GPA作用特异性的分析表明，除了E8期睫状神经节神经元外，该因子还能支持E8期背根神经节和E12期交感神经元的短期存活。在肝素存在的情况下，酸性和碱性成纤维细胞生长因子（FGF）也具有这种生物作用特异性范围。GPA的生物活性与FGF不同，因为它不受肝素增强，也不刺激鸡成纤维细胞的有丝分裂。
