Journal of Neuroscience, Vol 5, 1740-1754, Copyright © 1985 by Society for Neuroscience
Peripheral nerves in shiverer----dystrophic mouse chimeras: evidence that a non-Schwann cell component is required for axon ensheathment in vivo
AC Peterson
Peripheral nerves in dystrophic mice express multiple axon ensheathment
abnormalities. If an intrinsic deficiency expressed within the Schwann
cells themselves were to account for this neuropathy, then such cells,
existing in a chimera preparation, would be expected to express the same
ensheathment abnormalities, whereas a coexisting population of non-
dystrophic Schwann cells should not be similarly affected. The genotype of
myelinated Schwann cells in shiverer----dystrophic chimera was established
with immunocytochemical techniques. Shiverer myelin lacks the P1 component
of myelin basic protein (MBP), whereas dystrophic myelin appears to contain
normal levels of MBP. No correlation between the ensheathment
characteristics of the chimera spinal roots and the genotype of the local
Schwann cell population was found; both dystrophic Schwann cell populations
expressing normalized ensheathment characteristics and shiverer Schwann
cells failing to respond to the local presence of naked axons were
observed. These results require that a defective extra Schwann cell
component is involved in the pathogenesis of the dystrophic neuropathy.
Moreover, the normal realization of that component appears to be a
necessary prerequisite for shiverer Schwann cells to achieve full
ensheathment competence. Although a definitive identification of the cell
type(s) that expresses the dy gene locus has not been achieved in this
chimera preparation, the observations are consistent with defective
endoneurial fibroblast function.