Slavin A J, Johns T G, Orian J M, Bernard C C
Neuroimmunology Laboratory, La Trobe University, Bundoora, Australia.
Dev Neurosci. 1997;19(1):69-78. doi: 10.1159/000111187.
The assembly and function of central nervous system (CNS) myelin requires the coordinated expression of several myelin-specific proteins, including myelin oligodendrocyte glycoprotein (MOG). Despite the recent cloning of MOG, the function of this molecule is still unknown. Because MOG is a late marker of oligodendrocyte maturation and is exclusively expressed in the CNS on the outermost lamellae of the myelin membrane, it is possible that this molecule plays an important role in the control and maintenance of myelination. Furthermore, as a member of the immunoglobulin superfamily that carries the L2/HNK-1 epitope, it has also been suggested that MOG is involved in cell-cell interaction, perhaps functioning as an adhesive molecule for bundles of nerve fibres. In order to further delineate the role of MOG throughout development we have analysed, by immunoblotting, the developmental appearance and accumulation pattern of MOG in the CNS of three mammalian species. We have also purified MOG to homogeneity from five different species including rat, guinea pig, bovine, monkey and human. Immunoblotting revealed two major MOG bands at 28 and 55 kD in all species. The 55 kD band appears to be a dimer of the lower band although treatment with 2-mercaptoethanol or EDTA failed to abolish it. Purified MOG from all species also displayed faint reactivity with bands at 36, 48 and 78 kD. While the 78 kD band may represent a trimer of MOG, the identity of the other bands remains unknown. Developmental studies in mouse, rat, guinea pig and bovine showed at as for other myelin proteins, MOG displayed a caudorostral gradient of expression, appearing in the spinal cord before the brain. The sensitivity of the detection system used here allowed us to detect MOG protein earlier than in previous reports such that its presence was clearly demonstrated in the CNS of mice and rats at 14 and 10 days after birth, respectively. Analysis of MOG expression in a novel transgenic mouse model that has both delayed and reduced myelination revealed that, like other myelin proteins, MOG expression was delayed compared with normal littermates. These results demonstrate that the expression of MOG is similar in all species and is regulated in a manner consistent with other myelin-specific proteins.
中枢神经系统（CNS）髓磷脂的组装和功能需要几种髓磷脂特异性蛋白的协调表达，包括髓磷脂少突胶质细胞糖蛋白（MOG）。尽管最近克隆了MOG，但该分子的功能仍然未知。由于MOG是少突胶质细胞成熟的晚期标志物，并且仅在中枢神经系统中髓磷脂膜的最外层薄片上表达，因此该分子可能在髓鞘形成的控制和维持中起重要作用。此外，作为携带L2/HNK-1表位的免疫球蛋白超家族成员，也有人提出MOG参与细胞间相互作用，可能作为神经纤维束的粘附分子发挥作用。为了进一步阐明MOG在整个发育过程中的作用，我们通过免疫印迹分析了三种哺乳动物中枢神经系统中MOG的发育出现和积累模式。我们还从大鼠、豚鼠、牛、猴和人等五个不同物种中纯化出了均一的MOG。免疫印迹显示，所有物种中均有两条主要的MOG条带，分别位于28kD和55kD处。55kD的条带似乎是较低条带的二聚体，尽管用2-巯基乙醇或EDTA处理未能消除它。从所有物种中纯化的MOG与36kD、48kD和78kD处的条带也显示出微弱的反应性。虽然78kD的条带可能代表MOG的三聚体，但其他条带的身份仍然未知。在小鼠、大鼠、豚鼠和牛中的发育研究表明，与其他髓磷脂蛋白一样，MOG表现出从尾端到吻端的表达梯度，在脊髓中比在脑中更早出现。这里使用的检测系统的灵敏度使我们能够比以前的报告更早地检测到MOG蛋白，从而分别在出生后14天和10天在小鼠和大鼠的中枢神经系统中清楚地证明了它的存在。对一种具有延迟和减少髓鞘形成的新型转基因小鼠模型中MOG表达的分析表明，与其他髓磷脂蛋白一样，与正常同窝小鼠相比，MOG的表达延迟。这些结果表明，MOG在所有物种中的表达相似，并且其调节方式与其他髓磷脂特异性蛋白一致。
