Yanagisawa K, Moller J R, Duncan I D, Quarles R H
Section on Myelin and Brain Development, NINCDS, Bethesda, Maryland 20892.
J Neurochem. 1987 Dec;49(6):1912-7. doi: 10.1111/j.1471-4159.1987.tb02454.x.
The shaking pup is an X-linked canine mutant with a severe hypomyelination of the CNS. Proteolipid protein (PLP) and the related DM-20 protein were examined in this mutant by densitometric scanning of Western blots stained with PLP antiserum. In the spinal cord of 4-week-old mutants, PLP was reduced to less than 1% of the control level, which is a greater deficiency than was found for other myelin proteins. On Western blots of control spinal cord, PLP stained much more intensely than DM-20. However, on Western blots of the mutant spinal cord, a component with the electrophoretic mobility of DM-20 stained slightly more intensely with PLP antiserum than PLP itself. This component was shown to be DM-20 by its lack of reactivity with an antiserum raised to a synthetic peptide corresponding to part of the PLP sequence that is missing in DM-20. Thus PLP and DM-20 are expressed in approximately equal and greatly reduced amounts in the mutant spinal cord. Although PLP or DM-20 could not be detected in brain from the 4-week-old mutant, similar disproportional expression of these two proteins was demonstrated in both spinal cord and brain from a 10-week-old mutant pup. Immunostaining of tissue sections showed that the small amounts of PLP and/or DM-20 synthesized in the mutant are present in the thin myelin sheaths. The results suggest that the shaking pup could have a primary defect in the PLP gene leading to a severe deficiency of PLP and DM-20 as well as disproportional expression of these two proteins.
颤抖幼犬是一种X连锁犬类突变体，其中枢神经系统存在严重的髓鞘形成不足。通过用PLP抗血清染色的Western印迹进行光密度扫描，对该突变体中的蛋白脂蛋白（PLP）和相关的DM-20蛋白进行了检测。在4周龄突变体的脊髓中，PLP减少至对照水平的1%以下，这一比其他髓鞘蛋白更为严重的缺陷。在对照脊髓的Western印迹上，PLP染色比DM-20强烈得多。然而，在突变体脊髓的Western印迹上，一种具有DM-20电泳迁移率的成分用PLP抗血清染色比PLP本身略强。通过其与针对对应于DM-20中缺失的PLP序列部分的合成肽产生的抗血清缺乏反应性，表明该成分是DM-20。因此，PLP和DM-20在突变体脊髓中的表达量大致相等且大幅减少。虽然在4周龄突变体的大脑中未检测到PLP或DM-20，但在10周龄突变幼犬的脊髓和大脑中均显示出这两种蛋白的类似不成比例表达。组织切片的免疫染色显示，突变体中合成的少量PLP和/或DM-20存在于薄髓鞘中。结果表明，颤抖幼犬可能在PLP基因中存在原发性缺陷，导致PLP和DM-20严重缺乏以及这两种蛋白的不成比例表达。
