Madison D L, Krüger W H, Kim T, Pfeiffer S E
Department of Microbiology, University of Connecticut School of Medicine, Farmington 06030, USA.
J Neurosci Res. 1996 Aug 1;45(3):258-68. doi: 10.1002/(SICI)1097-4547(19960801)45:3<258::AID-JNR7>3.0.CO;2-C.
The small GTP-binding protein Rab3a is involved in regulated secretory pathways and is enriched in synaptic and neuroendocrine secretory vesicles. We have reported previously the developmental regulation of Rab3a in oligodendrocytes in culture and purified central nervous system myelin (Huber et al.: FEBS Lett 347: 273-278, 1994). Since multiple rab3 isoforms exist in the brain and may be associated with different secretory pathways, we have investigated the differential expression of the rab3 isoforms in oligodendrocytes, astrocytes, and Schwann cell line RT4-D6P2T. The expression of specific rab3 isoforms (rab3a-c) was detected by polymerase chain reaction (PCR) amplification and confirmed by sequence analyses. These data show that in addition to the previously reported expression in neurons, the two macroglial populations, astrocytes and oligodendrocytes, also express rab3 isoforms. Rab3b was preferentially amplified from purified, cultured astrocytes, while rab3a and rab3c were preferentially amplified from highly enriched populations of both cultured oligodendrocytes and those isolated directly from the brain by immunopanning. No novel rab3 isoform was detected in glia. These results indicate that glial cells in the brain express specific isoforms of the vesicular trafficking Rab3 protein family.
小GTP结合蛋白Rab3a参与调节性分泌途径，并在突触和神经内分泌分泌小泡中富集。我们之前报道过培养的少突胶质细胞和纯化的中枢神经系统髓鞘中Rab3a的发育调控（Huber等人：《欧洲生物化学会联合会快报》347：273 - 278，1994）。由于大脑中存在多种rab3亚型，且可能与不同的分泌途径相关，我们研究了rab3亚型在少突胶质细胞、星形胶质细胞和施万细胞系RT4 - D6P2T中的差异表达。通过聚合酶链反应（PCR）扩增检测特定rab3亚型（rab3a - c）的表达，并通过序列分析进行确认。这些数据表明，除了之前报道的在神经元中的表达外，两种大胶质细胞群体，即星形胶质细胞和少突胶质细胞，也表达rab3亚型。Rab3b优先从纯化的培养星形胶质细胞中扩增出来，而rab3a和rab3c优先从培养的少突胶质细胞以及通过免疫淘选直接从大脑中分离出的高度富集群体中扩增出来。在胶质细胞中未检测到新的rab3亚型。这些结果表明，大脑中的胶质细胞表达囊泡运输Rab3蛋白家族的特定亚型。
