Identification and characterization of a novel splice variant of MuSK

FEBS Lett. 1999 Jan 15;442(2-3):133-7. doi: 10.1016/s0014-5793(98)01641-x.


MuSK is a receptor tyrosine kinase that initiates the formation of neuromuscular junctions in response to agrin. Little is known about the ligand-induced activation and kinase-dependent signalling that leads to the clustering of acetylcholine receptors. The ectodomain of these molecule is composed of four Ig-like domains. We describe here the isolation of a novel MuSK splice variant that lacks the third Ig-like domain in its ectodomain. The corresponding RNA is the result of alternative splicing which eliminates two exons. There is 10 times less mRNA for this shorter form than for the long form of MuSK and both forms are regulated coordinately. They decrease strongly after birth and are elevated in denervated muscle. Gene transfer by muscle injection of MuSK DNA into individual muscle fibers demonstrates that kinase-induced acetylcholine receptor clustering caused by overexpression of the two kinases does not depend on the presence of the third Ig-like domain.

MeSH terms

  • Alternative Splicing / genetics*
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • Exons / genetics
  • Gene Expression Regulation, Developmental
  • Gene Transfer Techniques
  • Hindlimb
  • Injections
  • Isoenzymes / chemistry
  • Isoenzymes / genetics
  • Molecular Sequence Data
  • Muscle, Skeletal / embryology
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / metabolism
  • RNA, Messenger / analysis
  • Rats
  • Receptor Aggregation
  • Receptor Protein-Tyrosine Kinases / chemistry
  • Receptor Protein-Tyrosine Kinases / genetics*
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Receptors, Cholinergic / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Deletion / genetics


  • Isoenzymes
  • RNA, Messenger
  • Receptors, Cholinergic
  • MUSK protein, human
  • Receptor Protein-Tyrosine Kinases