Li J Y, Jahn R, Dahlström A
Department of Anatomy and Cell Biology, Göteborg University, Sweden.
Eur J Cell Biol. 1996 May;70(1):12-22.
Axonal transport and targeting of the t-SNAREs SNAP-25 and syntaxin 1 were investigated in the rat peripheral nervous system using a stop-flow (crush) technique. In crush-operated sciatic nerves, accumulations of SNAP-25 and syntaxin 1 immunoreactivities were detected as early as 1 h after operation, indicating fast axonal transport. The amounts increased on the proximal side of the crush with time after crushing. Distal accumulations of SNAP-25, representing recycling to the cell body, were less than 10% of the proximal accumulations, but 40% for syntaxin 1, 50% for synaptobrevin II and 70% for synaptophysin. Immunoelectron microscopic studies demonstrated that SNAP-25 and syntaxin 1 are present on pleiotropic membranes within a diameter of 50 to 100 nm in axons proximal to a crush. Distal to the crush, labeling for syntaxin 1 and SNAP-25 were sparse and barely detectable, respectively. In addition, the two proteins were found in the axolemma. In nerve terminals of the spinal cord, both proteins were concentrated around small synaptic vesicles (about 50 nm in diameter), whereas only very few gold particles were observed near the presynaptic membrane or the active zones.
利用停流（挤压）技术，在大鼠外周神经系统中研究了t-SNARE蛋白SNAP-25和 syntaxin 1的轴突运输及靶向作用。在挤压操作的坐骨神经中，术后1小时即可检测到SNAP-25和syntaxin 1免疫反应性的积累，表明轴突快速运输。挤压后，挤压近端的量随时间增加。代表向细胞体循环的SNAP-25远端积累量不到近端积累量的10%，但syntaxin 1为40%，突触小泡蛋白II为50%，突触素为70%。免疫电子显微镜研究表明，在挤压近端的轴突中，SNAP-25和syntaxin 1存在于直径50至100nm的多效性膜上。在挤压远端，syntaxin 1和SNAP-25的标记分别稀疏且几乎检测不到。此外，在轴膜中发现了这两种蛋白质。在脊髓神经末梢，两种蛋白质都集中在小突触小泡（直径约50nm）周围，而在突触前膜或活性区附近仅观察到极少数金颗粒。
