A unique role for Fyn in CNS myelination.


Journal Article

We analyzed the role of Fyn tyrosine kinase in CNS myelination by using fyn(-/-) null mutant mice, which express no Fyn protein. We found a severe myelin deficit in forebrain at all ages from 14 d to 1 year. The deficit was maximal at 1 month of age and was similar regardless of mouse strain background or whether it was determined by bulk isolation of myelin or by quantitation of myelin basic protein. To determine the cellular basis of the myelin deficit, we counted oligodendrocytes in tissue sections of mice expressing oligodendrocyte-targeted beta-galactosidase, and we used light and electron microscopy to examine the number and morphology of myelinated fibers and size of myelinated CNS structures. All of these parameters were reduced in fyn(-/-) mice. Unexpectedly, there were regional differences in the myelin deficit; in contrast to forebrain, fyn(-/-) cervical spinal cord exhibited no reduction in myelin content, number of oligodendrocytes, or number of myelinated fibers, nor was myelination delayed developmentally. We found that oligodendrocytes express Src, but there was no significant reduction of myelin content in null mutants lacking the Fyn-related kinases Src, Yes, or Lyn. Finally, we investigated the molecular features of Fyn that are required for myelination and found that a single amino acid substitution, which abolishes the tyrosine kinase activity of Fyn, resulted in a myelin deficit as great as that observed in the complete absence of Fyn protein. These results demonstrate that Fyn plays a unique role in myelination, one that requires its kinase activity.

Full Text

Cited Authors

  • Sperber, BR; Boyle-Walsh, EA; Engleka, MJ; Gadue, P; Peterson, AC; Stein, PL; Scherer, SS; McMorris, FA

Published Date

  • March 2001

Published In

Volume / Issue

  • 21 / 6

Start / End Page

  • 2039 - 2047

PubMed ID

  • 11245687

Pubmed Central ID

  • 11245687

Electronic International Standard Serial Number (EISSN)

  • 1529-2401

International Standard Serial Number (ISSN)

  • 0270-6474

Digital Object Identifier (DOI)

  • 10.1523/jneurosci.21-06-02039.2001


  • eng