Research on Expression of Myelin-Associated Glycoprotein in Regeneration of Central Nervous System

髓鞘相关糖蛋白（MAG）是髓鞘膜上的一种小分子蛋白，作为免疫球蛋白超家族的一员，可能在细胞与细胞的相互作用中发挥作用。本研究完成了小鼠MAG的cDNA克隆，发现了两种MAG异构体（small-MAG：S-MAG，large-MAG：L-MAG），它们通过不同的天然剪接机制表达。为了阐明神经系统再生的机制之一，我们研究了MAG在神经系统损伤后髓鞘再生中的作用。本研究的主要结果如下：1）建立了铜中毒脱髓鞘和髓鞘再生的实验模型; 2）建立了大脑中动脉阻塞继发性脱髓鞘的模型; 3）分别制备了抗L-MAG和抗S-MAG的抗体; 4）制备了抗L-MAG和抗S-MAG的抗体; 5）制备了抗L-MAG和抗S-MAG的抗体; 6）制备了抗S-MAG的抗体; 7）制备了抗L-MAG的抗体; 8）制备了抗S-MAG的抗体; 9）制备了抗L-MAG的抗体; 10）制备了抗S-MAG的抗体。5）检测了包括MAG在内的脑蛋白的变化。6）在震颤突变小鼠中，L-MAG在整个发育过程中几乎不表达。因此，7）完成了人MAG的cDNA克隆，获得了人MAG的克隆。

The myelin-associated glycoprotein (MAG) is minor myelin membrans proteins and may play a role in cell to cell interaction as a member of immunoglobulin superfamily. We completed cDNA cloning of mouse MAG and found two kinds of MAG isoforms (small-MAG : S-MAG, large-MAG : L-MAG) which are expressed by alter native splicing mechanism. To clarify one of mechanisms of regeneration in nervous system, we examined roles of MAG on remyelination after damage of nervous system. The results of this research program are as follows.1) We established an experimental model of demyelination and remyelination by Cuprizon intoxication.2) An model of secondary demyelination by occlusion of middle cerebral artery was established.3) We prepared an anti-L-MAG and an anti-S-MAG antibodies from synthetic peptides of c-termini to L-MAG and S-MAG respectively.4) The L-MAG isoform was induced during remyelinating stage after demyelination by Cuprison intoxication.5) Changes of brain proteins including MAG were examined.6) In the quaking mutant mouse, L-MAG was scarcely expressed throughout development.Therefore, L-MAG is revealed to be important for normal myelination.7) We have completed cDNA cloning of human MAG and obtained only L-MAG clone.