Higgins G A, Schmale H, Bloom F E, Wilson M C, Milner R J
Department of Neurobiology and Anatomy, University of Rochester School of Medicine, NY 14642.
Proc Natl Acad Sci U S A. 1989 Mar;86(6):2074-8. doi: 10.1073/pnas.86.6.2074.
The protein encoded by the rat brain cDNA 1B236 has been shown to be identical to myelin-associated glycoprotein (MAG). In this report we describe the cellular distribution of 1B236/MAG mRNA transcripts in rat brain by using in situ hybridization. At postnatal day 20, large numbers of 1B236/MAG mRNA-containing oligodendrocytes are concentrated in myelinated fiber tracts and throughout gray matter regions. The presence of high levels of 1B236/MAG mRNA within oligodendrocytes at postnatal day 20 is consistent with the proposed role of MAG in formation of the myelin sheath during development. In the adult brain, our results suggest that not only is 1B236/MAG mRNA expressed at reduced levels within oligodendrocytes but also 1B236/MAG or a 1B236/MAG-like mRNA is present within neurons. This localization is consistent with the results of previous immunocytochemical studies using antibodies against the 1B236/MAG mRNA with different cell-type-specific patterns of expression suggests that oligodendrocytes and neurons employ different mechanisms for regulating the same gene. Thus, different cell types may use a similar cell adhesion molecule both during myelinogenesis and in the mature nervous system.
大鼠脑cDNA 1B236编码的蛋白质已被证明与髓鞘相关糖蛋白（MAG）相同。在本报告中，我们通过原位杂交描述了1B236/MAG mRNA转录本在大鼠脑中的细胞分布。在出生后第20天，大量含有1B236/MAG mRNA的少突胶质细胞集中在有髓纤维束和整个灰质区域。出生后第20天少突胶质细胞内高水平的1B236/MAG mRNA的存在与MAG在发育过程中髓鞘形成中的作用一致。在成体脑中，我们的结果表明，不仅1B236/MAG mRNA在少突胶质细胞内的表达水平降低，而且神经元内也存在1B236/MAG或1B236/MAG样mRNA。这种定位与先前使用针对1B236/MAG的抗体进行免疫细胞化学研究的结果一致，不同细胞类型特异性的表达模式表明少突胶质细胞和神经元采用不同的机制来调节同一基因。因此，不同的细胞类型在髓鞘形成过程中和成熟神经系统中可能使用相似的细胞粘附分子。
