Perry G W, Burmeister D W, Grafstein B
J Neurosci. 1987 Mar;7(3):792-806. doi: 10.1523/JNEUROSCI.07-03-00792.1987.
Fast axonal transport of protein was examined in regenerating goldfish optic axons after a lesion of either the optic tract or optic nerve, which revealed changes in the original intact optic axon segments or in the newly regenerated axon segments, respectively. In animals killed either 6 or 24 hr after injection of 3H-proline into the eye, labeling of total fast-transported protein in the original axon segments was increased by 2 d after the lesion, reached a peak of nearly 20 X normal at 2 weeks, and then declined to a level somewhat above normal at 12 weeks. When the labeling of individual transported proteins was examined by 2-dimensional gel electrophoresis, it was found that no new labeled proteins appeared during regeneration, but all proteins examined showed an increase in labeling. Among the various proteins, there was great variation in the magnitude and time course of the labeling increase. The largest increase, to nearly 200 X normal with 6 hr labeling, was seen in a protein with a molecular weight of 45 kDa and a pl of about 4.5, resembling a protein that has previously been designated a "growth-associated protein" (GAP-43; Skene and Willard, 1981a). The proteins showing increased labeling included a small fraction of cytoskeletal proteins (alpha-tubulin, beta-tubulin, and actin) that was apparently transported at a much faster rate than is usually expected of these constituents. In the new axon segments, the total protein labeling was increased by 1 week after the lesion, remained elevated at a nearly constant level of about 7 X normal from about 2 to 5 weeks, and then declined to levels somewhat above normal by 12 weeks. The 45 kDa protein again showed the largest increase, and became the single most prominently labeled constituent in the new axons. On the basis of the time course of labeling in both original and new axon segments during regeneration, the fast-transported proteins were tentatively separated into 5 classes that may represent groups of proteins that are coregulated during regeneration. They may conceivably correspond to different functional or structural entities within the neuron.
在视束或视神经损伤后，对再生的金鱼视神经轴突中蛋白质的快速轴突运输进行了检测，结果分别显示了原始完整视神经轴突段或新再生轴突段的变化。在向眼内注射³H-脯氨酸后6小时或24小时处死的动物中，损伤后2天原始轴突段中总快速运输蛋白的标记增加，在2周时达到近正常水平的20倍峰值，然后在12周时降至略高于正常的水平。当通过二维凝胶电泳检测单个运输蛋白的标记时，发现再生过程中没有出现新的标记蛋白，但所有检测的蛋白标记均增加。在各种蛋白质中，标记增加的幅度和时间进程存在很大差异。在一种分子量为45 kDa、等电点约为4.5的蛋白质中观察到最大的增加，6小时标记时达到近正常水平的200倍，类似于先前被指定为“生长相关蛋白”（GAP-43；Skene和Willard，1981a）的一种蛋白质。显示标记增加的蛋白质包括一小部分细胞骨架蛋白（α-微管蛋白、β-微管蛋白和肌动蛋白），其运输速度明显比这些成分通常预期的要快得多。在新的轴突段中，损伤后1周总蛋白标记增加，在约2至5周内保持在近正常水平的7倍左右的恒定升高水平，然后在12周时降至略高于正常的水平。45 kDa蛋白再次显示出最大的增加，并成为新轴突中最突出标记的单一成分。根据再生过程中原始和新轴突段标记的时间进程，快速运输蛋白被初步分为5类，可能代表在再生过程中共同调节的蛋白质组。可以想象，它们可能对应于神经元内不同的功能或结构实体。
