DYSMELINATION IN THE X-LINKED MYELIN MUSTANTS

在过去的五年里，分子生物学的应用 髓鞘突变体研究的策略和新的细胞技术 使得我们有可能从一个已经确定的基因中 在神经系统中的细胞表达缺陷。 在性连锁的 髓磷脂突变体已经提出， 蛋白脂质蛋白（PLP），主要的中枢神经系统髓鞘蛋白，是可能的 因为他们的髓鞘发育不良。 该项目的长期目标是 在这些突变体中的两个中解决这一假设，即髓磷脂缺陷型（MD） 大鼠和狗摇动（sh）小狗，并应用跨学科 这些疾病的分子遗传学和细胞特征的方法。 两个具体目标解决这些目标：1）研究的长期影响， 少突胶质细胞和其他神经胶质细胞上的PLP突变， 活的md大鼠品系，并在斑块的非髓鞘形成的光学 具有髓鞘嵌合体的老年雌性杂合子md大鼠的神经。 形态学、组织培养和分子（mRNA分析和原位） 杂交）方法将用于确定神经胶质细胞存活， 在这两种情况下的分工和职能。 此外，研究 粗面内质网（RER）扩张，这是唯一的 两种突变体中少突胶质细胞缺陷的标志，将进行 在CNS的培养物中。 计划鉴定培养中的细胞 用免疫标记法检测肿胀的粗面内质网， 扩张的粗面内质网，使用髓鞘和粗面内质网相关的抗体， proteins. 2)使用这两种突变体作为移植细胞的受体， 研究他们的CNS被少突胶质细胞髓鞘化的潜力， 正常PLP基因或正常雪旺细胞，并确定作用 其他神经胶质细胞和它们的营养因子 髓鞘形成障碍 此外，使用基因转移的潜力 含有正常PLP基因序列的逆转录病毒载体将被 在体外和体内进行。 这样的做法将有助于 确定这种基因转移是否会导致更全面的纠正， 髓磷脂紊乱比由局部移植带来的。 这些研究对X连锁髓鞘形成障碍具有重要意义， 伙计 Pelizaeus-Merzbacher病 这些研究还将探讨 关于轴突长期髓鞘形成的可行性的问题， 脱髓鞘疾病，如多发性硬化症，和潜在的 在这些疾病中使用移植的神经胶质细胞和雪旺细胞。 的 因此，这些实验提出的基本问题将是重要的 对人类疾病和神经生物学意义重大。

Within the last five years, the application of molecular biological strategies and new cellular techniques to the study of the myelin mutants have made it possible to trace the pathway from an identified genetic defect to its cellular expression in the nervous system. In the sex-linked myelin mutants it has been proposed that a mutation in the gene for proteolipid protein (PLP), the major CNS myelin protein, is the likely cause of their dysmyelination. The long term goals of this project are to address this hypothesis in two of these mutants, the myelin deficient (md) rat and the canine shaking (sh) pup, and apply an interdisciplinary approach to the molecular genetic and cellular features of these disorders. Two specific aims address these goals: 1) Study the long term effect of the putative PLP mutation on oligodendrocytes and other glia in a longer- lived strain of md rat, and in patches of non-myelination in the optic nerves of aged female heterozygote md rats who have myelin mosaicism. MOrphologic, tissue culture and molecular (mRNA analysis and in situ hybridization) approaches will be used to determine glial cell survival, division and function in these two situations. In addition, study of the distension of the rough endoplasmic reticulum (RER), which is the unique hallmark of the oligodendrocyte defect in both mutants, will be carried out in cultures of the CNS. It is planned to identify the cells in culture with swollen RER using immunolabelling, and the accumulating material in the distended RER, using antibodies to the myelin and RER associated proteins. 2) Use the two mutants as recipients of grafted cells, both to study the potential for their CNS to be myelinated by oligodendrocytes with the normal PLP gene or by normal Schwann cells, and to determine the role that other glial cells and their trophic factors have on the dysmyelination. In addition, the potential for gene transfer using a retroviral vector containing sequences of the normal PLP gene will be carried out both in vitro and in vivo. Such an approach will help determine whether such gene transfer results in more global correction of the myelin disorders than that brought about by local transplantation. These studies have importance to the X-linked dysmyelinating disorder in man. Pelizaeus-Merzbacher disease. These studies will also address questions about the feasibility of long term myelination of axons in demyelinating disorders such as multiple sclerosis, and the potential for using transplanted glial cells and Schwann cells in such diseases. The basic questions which these experiments ask will therefore be of importance to human disease and of significance to neurobiology.