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 使得从一种已识别的基因中追踪这条途径成为可能 缺陷于其在神经系统中的细胞表达。在与性有关的 髓鞘突变体有人提出，髓鞘基因的突变 蛋白脂蛋白(PLP)是主要的中枢神经系统髓鞘蛋白，可能是 因为他们有髓鞘障碍。这个项目的长期目标是 在这些突变体中的两个，髓鞘缺陷(MD)中解决了这一假设 大鼠和小狗摇动(Sh)幼崽，并应用跨学科 探讨这些疾病的分子遗传学和细胞学特征。 有两个具体目标涉及这些目标：1)研究 少突胶质细胞和其他胶质细胞上可能的PLP突变- MD大鼠的活体株，以及视神经中的非髓鞘斑块 髓鞘嵌合症老年雌性杂合子MD大鼠的神经。 形态、组织培养和分子(信使核糖核酸分析和原位 杂交)方法将被用来确定神经胶质细胞的存活， 在这两种情况下的分工和作用。此外，还研究了 粗面内质网(RER)扩张，这是唯一 这两个突变体的少突胶质细胞缺陷的标志将被执行 在中枢神经系统的文化中。计划对培养中的细胞进行鉴定 用免疫标记法标记肿胀的粗面内质网，并在 利用髓鞘抗体和粗面内质网相关抗体扩大的粗面内质网 蛋白质。2)使用这两个突变体作为移植细胞的受体，两者都可以 研究少突胶质细胞对其中枢神经系统髓鞘形成的影响 正常的PLP基因或由正常的雪旺细胞，并确定其作用 其他神经胶质细胞及其营养因子对 髓鞘障碍。此外，使用基因转移的可能性 含有正常PLP基因序列的逆转录病毒载体将被 在体外和体内都进行了研究。这样的方法将有所帮助。 确定这样的基因转移是否会导致更全面的纠正 髓鞘紊乱比局部移植所带来的髓鞘紊乱更严重。 这些研究对X连锁的髓鞘障碍有重要意义。 天哪。Pelizaeus-Merzbacher病。这些研究还将解决 对轴突长期髓鞘形成可行性的质疑 多发性硬化症等脱髓鞘疾病，以及 在此类疾病中使用移植的神经胶质细胞和雪旺细胞。这个 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具有重要意义。

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.