Identification of the New Isoforms of Mouse Myelin Basic Protein: The Existence of Exon 5a

J. Aruga, H. Okano, K. Mikoshiba

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Abstract: Myelin basic protein (MBP) is a major constituent in the myelin of the CNS. In mice, five forms of MBPs (14 kDa, two types of 17 kDa, 18.5 kDa, and 21.5 kDa) encoded by separate mRNAs have been identified based on cDNA cloning studies. These mRNAs are considered to be produced by alternative splicing from a single gene composed of seven exons. Here we report the existence of two novel MBP mRNAs encoding 19.7‐kDa and 21‐kDa MBPs identified by cDNA cloning using the polymerase chain reaction. Both of these MBPs contain a sequence of a previously unidentified exon of 66 nucleotides, which was mapped to be just 5’of exon 5 in the MBP gene. MBP mRNAs containing this novel exon (exon 5a) belong to a minor population in the whole brain and PNS and are somewhat enriched in the spinal cord. Exon 5a encodes a very hydrophobic segment rich in valine residues, which presumably forms a β‐pleated sheet.

Original languageEnglish
Pages (from-to)1222-1226
Number of pages5
JournalJournal of Neurochemistry
Issue number4
Publication statusPublished - 1991 Apr
Externally publishedYes


  • Myelin
  • Myelin basic protein
  • mRNA splicing

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


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