Fink D J, Gainer H
J Cell Biol. 1980 May;85(2):175-86. doi: 10.1083/jcb.85.2.175.
The injection of [2,3-3H]N-succinimidyl propionate ([3H]N-SP) into the rat sciatic nerve was used to covalently label both intra- and extra-axonal proteins. While extra-axonal proteins (e.g., myelin proteins) remained in the injection site, the intra-axonal proteins were transported in both the anterograde and retrograde directions. The mobile labeled proteins appeared to move by normal axonal transport processes because: (a) autoradiographic studies showed that they were localized exclusively within the axon at considerable distances from the injection site, (b) specific and identifiable proteins (by SDS gel electrophoresis) moved at expected rates in the anterograde direction, and (c) an entirely different profile of proteins moved in the anterograde vs. retrograde direction. This novel experimental approach to axonal transport, which is independent of de novo protein synthesis, provided a unique view of slow anterograde transport, and particularly of retrograde transport of endogenous proteins. A large quantity of a 68,000 mol wt proteins, moving at approximately 3-6 mm/day, dominated the retograde transport profile. [3H]N-SP, therefore, represents a new and unique "vital stain" which may find many applications in cell biology.
将[2,3-3H]N-琥珀酰亚胺基丙酸酯（[3H]N-SP）注入大鼠坐骨神经，用于共价标记轴突内和轴突外的蛋白质。轴突外蛋白质（如髓磷脂蛋白）留在注射部位，而轴突内蛋白质则沿顺行和逆行方向运输。移动的标记蛋白似乎通过正常的轴突运输过程移动，因为：（a）放射自显影研究表明，它们仅位于距注射部位相当远的轴突内，（b）特定且可识别的蛋白质（通过SDS凝胶电泳）以预期的速率沿顺行方向移动，（c）顺行和逆行方向移动的蛋白质谱完全不同。这种独立于从头合成蛋白质的轴突运输新实验方法，为慢速顺行运输，特别是内源性蛋白质的逆行运输提供了独特的视角。一种大量的68,000道尔顿分子量的蛋白质，以约3-6毫米/天的速度移动，主导了逆行运输谱。因此，[3H]N-SP代表了一种新的独特的“活体染色剂”，可能在细胞生物学中有许多应用。
