Mikoshiba K, Okano H, Inoue Y, Fujishiro M, Takamatsu K, Lachapelle F, Baumann N, Tsukada Y
Division of Regulation of Macromolecular Function, Osaka University, Japan.
Brain Res. 1987 Sep;432(1):111-21. doi: 10.1016/0165-3806(87)90013-7.
Myelin deficiency (mld) is an autosomal recessive mutation in mice and is considered to be allelic to the shiverer (shi) mutation. Mld mice are characterized by hypomyelination of the central nervous system (CNS). They show typical symptoms such as tremor, tonic convulsion and ataxic movement. Subcellular fractionation of the CNS revealed that the MBP bands were greatly decreased in the P2A (myelin) fraction and the total content of myelin basic protein (MBP) was much lower than that in the control in all parts of the CNS. Sections from mld mice were examined by immunohistochemical tests with MBP antiserum, and a mosaic expression of MBP was found in the myelin of the mld mice. Since the major dense line is considered to be composed mainly of MBP, we investigated the myelin of mld mice by electron microscopy and found that there were 3 types of myelin: (1) a normal type compact myelin with a major dense line, (2) a shiverer-type myelin with no major dense line, and (3) a mixed-type myelin, in which within a myelin lamella the major dense line abruptly changes to cytoplasm of oligodendrocytes.
髓磷脂缺乏症（mld）是小鼠中的一种常染色体隐性突变，被认为与颤抖鼠（shi）突变等位。mld小鼠的特征是中枢神经系统（CNS）髓鞘形成不足。它们表现出典型症状，如震颤、强直性惊厥和共济失调运动。对中枢神经系统进行亚细胞分级分离显示，在P2A（髓磷脂）级分中MBP条带大幅减少，并且在中枢神经系统所有部位，髓磷脂碱性蛋白（MBP）的总含量远低于对照组。用MBP抗血清通过免疫组织化学试验检查mld小鼠的切片，发现在mld小鼠的髓鞘中存在MBP的镶嵌表达。由于主要致密线被认为主要由MBP组成，我们通过电子显微镜研究了mld小鼠的髓鞘，发现有3种类型的髓鞘：（1）具有主要致密线的正常型紧密髓鞘，（2）没有主要致密线的颤抖鼠型髓鞘，以及（3）混合型髓鞘，其中在一个髓鞘板层内主要致密线突然变为少突胶质细胞的细胞质。
