REGIONAL LOCALIZATION OF RNA AND PROTEIN-METABOLISM IN SCHWANN-CELLS INVIVO
REGIONAL LOCALIZATION OF RNA AND PROTEIN-METABOLISM IN SCHWANN-CELLS INVIVO
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DOI：
10.1007/bf01188399
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发表时间：
1990-06-01
期刊：
影响因子：
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通讯作者：
MATTINGLY, G
中科院分区：
文献类型：
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作者：
GOULD, RM;MATTINGLY, G
雪旺细胞形成并维持广泛的髓鞘，其大部分脂质和蛋白质合成局限于节间中心致密的“核周”区。利用戏弄纤维和定量电镜放射自显影，我们证明了额外的蛋白质合成发生在许旺细胞质的漫长过程中。这种“所谓的”表面细胞质通道网络形成了一个分支和吻合的阵列，延伸到核周区域和远处的偏执区之间。蛋白质合成显然不会从这个表面网络延伸到施密特-兰特曼切口或围住致密髓磷脂的副神经环。为了在这些漫长的过程中维持蛋白质的合成，雪旺细胞以每天0.1毫米的速度沿着细胞质表面通道运输一部分RNA，这似乎略低于培养海马神经元树突上的RNA运输速度（每天0.5毫米）。标记的RNA从雪旺细胞核运输到较长通道的副神经末梢需要近一周的时间。这种扩展蛋白合成的存在并不局限于髓鞘雪旺细胞。与小口径轴突相关的雪旺细胞过程似乎也合成了一些自己的蛋白质，因为催化局部翻译事件所需的RNA被转运到这些过程中。
Schwann cells, which form and maintain extensive myelin sheaths, have the bulk of their lipid and protein synthesis restricted to the compact ''perinuclear'' zone at the centre of the internode. Using teased fibre and quantitative electron microscopical autoradiography, we demonstrated that additional protein synthesis takes place in the lengthy processes of Schwann cell cytoplasm. This ''so-called'' superficial cytoplasmic channel network forms a branching and anastomozing array that stretches between the perinuclear region and the distant paranodes. Protein synthesis apparently does not extend from this surface network into the Schmidt-Lanterman incisures or paranodal loops that circumscribe compact myelin. To maintain protein synthesis in these lengthy processes, Schwann cells transport a portion of their RNA along the superficial cytoplasmic channels at a rate (0.1 mm per day) that appears to be slightly lower than the transport rate reported for RNA along dendrites of hippocampal neurons in culture (0.5 mm per day). Nearly a week is required for labelled RNA to be transported from the Schwann cell nucleus to the paranodal terminals of the longer channels. The existence of this extended protein synthesis is not limited to myelinating Schwann cells. Schwann cell processes associated with small calibre axons also appear to synthesize some of their own proteins as the RNA needed to catalyze local translational events is transported into these processes.