Peterson A C, Bray G M
J Comp Neurol. 1984 Aug 10;227(3):348-56. doi: 10.1002/cne.902270305.
In shiverer mice, the P1 component of myelin basic protein (MBP) is deficient in both the central nervous system (CNS) and peripheral nervous system (PNS) but compact myelin is more grossly defective in the CNS. In the PNS, myelin exhibits a normal periodic structure, and although examples of subtle abnormalities of shiverer Schwann cell ultrastructure have been described previously, myelin thickness has been reported as unremarkable when observed by light microscopy. We report a quantitative investigation of the myelin sheath thickness of shiverer Schwann cells in which a mild but apparently consistent hypomyelination of axons ensheathed by shiverer Schwann cells was observed. This abnormality was expressed both in the peripheral nerves of a homozygous shiverer mouse and in the shiverer Schwann cells populating the mosaic nerves of a mature shiverer in equilibrium normal mouse chimaera. In addition, multiple interlamellar gaps was found to be a highly consistent feature of shiverer myelin. These observations extend the description of the peripheral nerve defects expressed in shiverer mice and further define these abnormalities as direct consequences of the shiverer Schwann cells' intrinsic genotype. In light of these results, a significant role for P1 in the formation and/or maintenance of normal myelin in the PNS is suggested.
在颤抖小鼠中，髓鞘碱性蛋白（MBP）的P1成分在中枢神经系统（CNS）和外周神经系统（PNS）中均有缺陷，但致密髓鞘在CNS中的缺陷更为严重。在PNS中，髓鞘呈现正常的周期性结构，尽管先前已描述过颤抖雪旺细胞超微结构的细微异常实例，但通过光学显微镜观察时，髓鞘厚度并无明显异常。我们报告了一项对颤抖雪旺细胞髓鞘厚度的定量研究，其中观察到由颤抖雪旺细胞包裹的轴突存在轻度但明显一致的髓鞘形成不足。这种异常在纯合颤抖小鼠的外周神经以及平衡正常小鼠嵌合体中成熟颤抖小鼠的镶嵌神经中的颤抖雪旺细胞中均有表现。此外，发现多层间隙是颤抖小鼠髓鞘的一个高度一致的特征。这些观察结果扩展了对颤抖小鼠中表达的外周神经缺陷的描述，并进一步将这些异常定义为颤抖雪旺细胞内在基因型的直接后果。鉴于这些结果，提示P1在PNS中正常髓鞘的形成和/或维持中起重要作用。
