Molecular Pathology of the dysmyelinating diseases and generation of the model animals

Pelizaeus-Merzbacher病（PMD）是一种X连锁的中枢神经系统髓鞘发育障碍疾病，其特征是早发性眼球震颤和痉挛性四肢瘫痪（运动发育迟缓）。它通常在婴儿期或儿童期是致命的。本研究采用PCR-SSCP和PCR产物直接测序的方法对26个PMD家系的髓磷脂蛋白脂质蛋白（PLP）基因进行了分析，发现了7个新的突变，包括3个错义突变、1个无义突变、1个火焰移位突变和2个剪接突变。其中一个家族包括3名男性，他们表现为青少年形式的PMD，伴有由剪接突变引起的痉挛性截瘫。其余19个PMD家系的PLP基因外显子均未发现突变。目前正在调查这些PMD家庭中疾病原因的进一步分析。为了了解PMD的表型与PLP突变和功能的关系，我们建立了外源PLP/DM 20基因在培养细胞中的表达系统，并在MMTV启动子控制下获得了表达DM 20的C6细胞，制备了DM 20多肽的抗体，研究了DM 20的细胞内定位。进行这些细胞的纯化。

Pelizaeus-Merzbacher disease (PMD) is an X-linked dysmyelinating disorder of the central nervous system, characterized by an early onset of nystagmus and spastic quadriplegia (motor developmental delay). It is usually fatal in infancy or childhood. In this study we analyzed the myelin proteolipid protein (PLP) gene of the 26 PMD families by PCR-SSCP followed by direct sequencing of the PCR products and then found seven novel mutations including three missense, one nonsense, one flame-shift, and two splice mutations in the PLP genes. One of the families includes 3 males who have manifestations of the juvenile form of PMD with spastic paraplegia caused by a splice mutation. There was no mutation in the exons of the PLP genes of the remaining 19 PMD families. Further analysis of the causes of the disease in those PMD families are now under investigations. To know the relationship of phenotype of PMD with the mutation and the function of PLP,we established a system for expression of the exogenous PLP/DM20 gene in cultured cells before trying to make a mouse model for PMD.We obtained C6 cells expressing DM20 under the control of the MMTV promoter and prepared antibodies against DM20-peptides to investigate the intracellular localization of DM20. Characterzation of those cells are proceeded.