Hypomyelinated mutant mice IV: peripheral myelin in jp msd.

This study compares peripheral myelination in a specific subdivision of the sciatic nerve of jp msd and unaffected littermate mice. No significant differences are found in numbers of myelinated and unmyelinated axons, diameters of axons, thickness of myelin sheaths relative to axon diameter, extent of unmyelinated axons segregation by Schwann cell processes, or in the ultrastructure of myelin and Schwann cells. By contrast, jp msd mutant mice show severe CNS hypomyelination. This evidence, that the jp msd mutation affects only oligodendrocytes, distinguishes mutations at this locus from others producing CNS hypomyelination in which PNS myelin is also affected.