Slowly migrating axonal polypeptides. Inequalities in their rate and amount of transport between two branches of bifurcating axons.
Slowly migrating axonal polypeptides. Inequalities in their rate and amount of transport between two branches of bifurcating axons.
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DOI：
10.1083/jcb.82.1.174
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发表时间：
1979-07
影响因子：
7.8
通讯作者：
Kurokawa, M
中科院分区：
文献类型：
--
作者：
Mori, H;Komiya, Y;Kurokawa, M
对成年大鼠背根神经节(L5)内的多肽进行了放射性标记，并用十二烷基硫酸钠-聚丙烯酰胺平板凝胶电泳法和荧光照相技术分析了在坐骨神经(外周轴突)和背根(中央轴突)中缓慢迁移的成分。特别是，比较了六种主要多肽，即三联体(参考文献15，摩尔WT分别为200,000,160,000和68,000道尔顿)、α-微管蛋白和β-微管蛋白以及肌动蛋白在两个轴突分支之间的转运速度和数量。在外周轴突中，三联体、微管蛋白和肌动蛋白的前锋分别以2-3 mm/d、9-13 mm/d和约19 mm/d的速度移动。中央轴突的对应值分别为1~2 mm/d、3~4 mm/d和约4 mm/d，表明分叉轴突的两个分支之间的运输速率存在明显的不对称。发现标记的三联体、微管蛋白和肌动蛋白在外周比在中央轴突中迁移的量更大。两个分支之间不对称的另一个显著方面与微管/三联体比率有关，这一比率在外周分支中明显更高。神经节中与微管蛋白和肌动蛋白相关的相当大比例的放射性活动是非迁移性的，被认为主要来自轴突周围卫星细胞。相反，大多数标记的三联体是迁移性的，这表明卫星细胞中实际上不存在三联体多肽。从轴突体积和轴突生长的角度讨论了外周-中枢不等长在轴浆运输缓慢中的可能意义。
Polypeptides in the dorsal root ganglion (L5) of the adult rat were radioactively labeled, and components slowly migrating in the sciatic nerve (peripheral axons) and dorsal root (central axons) were analyzed, using SDS-polyacrylamide slab gel electrophoresis and fluorography. In particular, the transport rates and amounts of six major polypeptides, i.e., the triplet (reference 15; with mol wts of 200,000, 160,000, and 68,000 daltons), alpha- and beta-tubulins and actin were compared between the two axon branches. In peripheral axons, fronts of the triplet, tubulins, and actin migrate at 2-3 mm/d, 9-13 mm/d and approximately 19 mm/d, respectively. The corresponding values in central axons are 1-2 mm/d, 3-4 mm/d, and approximately 4 mm/d, indicating an obvious asymmetry in the transport rate between the two branches of bifurcating axons. A greater amount of labeled triplet, tubulins, and actin each is found to migrate in peripheral than in central axons. Another striking aspect of asymmetry between the two branches relates to the tubulins/triplet ratio which is significantly higher in the peripheral branch. Considerable proportions of radioactivities associated with tubulins and actin in the ganglion are nonmigratory, which are thought to derive mostly from periaxonal satellite cells. In contrast, most if not all of the labeled triplet is migratory, suggesting a virtual absence of triplet polypeptides in satellite cells. The possible significance of peripheral-central inequalities in slow axoplasmic transport is discussed from the viewpoints of axon volume and axonal outgrowth.