Morphometric Analysis of Normal, Mutant, and Transgenic CNS: Correlation of Myelin Basic Protein Expression to Myelinogenesis

H. David Shine*, Carol Readhead, Brian Popko, Leroy Hood, Richard L. Sidman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

Abstract: The neurological mutant mice shiverer (shi) and myelin deficient (shimld) lack a functional gene for the myelin basic proteins (MBP), have virtually no myelin in their CNS, shiver, seize, and die early. Mutant mice homozygous for an MBP transgene have MBP mRNA and MBP in net amounts approximately 25% of normal, have compact myelin, do not shiver or seize, and live normal life spans. We bred mice with various combinations of the normal, transgenic, shi, and shimld genes to produce mice that expressed MBP mRNA at levels of 0, 5, 12.5, 17.5, 50, 62.5, and 100% of normal. The CNS of these mice were analyzed for MBP content, tissue localization of MBP, degree of myelination, axon size, and myelin thickness. MBP protein content correlated with predicted MBP gene expression. Immunocytochemical staining localized MBP to white matter in normal and transgenic shi mice with an intensity of staining comparable to the degree of MBP gene expression. An increase in the percentage of myelinated axons and the thickness of myelin correlated with increased gene expression up to 50% of normal. The percentage of myelinated axons and myelin thickness remained constant at expression levels greater than 50%. The presence of axons loosely wrapped with oligodendrocytic membrane in mice expressing lower amounts of MBP mRNA and protein suggested that the oligodendroglia produced sufficient MBP to elicit axon wrapping but not enough to form compact myelin. Mean axon circumference of myelinated axons was greater than axon circumference of unmyelinated axons at each level of gene expression, further evidence that oligodendroglial cells preferentially myelinate axons of larger caliber. These data suggest that oligodendroglial function is governed in part by the degree of MBP expression.

Original languageEnglish (US)
Pages (from-to)342-349
Number of pages8
JournalJournal of neurochemistry
Volume58
Issue number1
DOIs
StatePublished - Jan 1992

Keywords

  • CNS morphometry
  • Myelin basic protein
  • Myelin development
  • Myelin gene expression
  • Myelin‐deficient mouse
  • Shiverer mouse
  • Transgenic mouse

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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