Genomic organization and structure of the 3' region of human MUC3: alternative splicing predicts membrane-bound and soluble forms of the mucin

Biochem Biophys Res Commun. 1999 Oct 5;263(3):728-36. doi: 10.1006/bbrc.1999.1466.


The MUC3 gene encodes a large, glycosylated mucin produced by intestinal epithelial cells to form a protective barrier against the external environment. Recently published cDNA sequences for the carboxyl-terminal region of MUC3 polypeptide indicated that rodent Muc3 possesses two epidermal growth factor (EGF)-like domains, and putative transmembrane and cytoplasmic domains, whereas the sequence of human MUC3 predicted termination after the first EGF-like domain. Here we describe the complete genomic sequence encompassing the carboxyl terminal region of human MUC3, revealing the boundaries of 11 exons. RT-PCR and cDNA library cloning experiments indicate that the gene is alternatively spliced, yielding a major membrane-bound form as well as multiple soluble forms. Thus, this work indicates that both membrane-bound and soluble MUC3 mucin proteins are produced by alternative splicing of a single gene. A potentially important polymorphism involving a Tyr residue with a proposed role in signalling is described as well.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3' Untranslated Regions / genetics*
  • Alternative Splicing*
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Membrane / metabolism
  • Conserved Sequence
  • Cytoplasm / metabolism
  • Epidermal Growth Factor / chemistry
  • Exons
  • Humans
  • Mice
  • Molecular Sequence Data
  • Mucin-3
  • Mucins / chemistry*
  • Mucins / genetics*
  • Mucins / metabolism
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • 3' Untranslated Regions
  • Muc3 protein, mouse
  • Muc3 protein, rat
  • Mucin-3
  • Mucins
  • Neoplasm Proteins
  • Epidermal Growth Factor

Associated data

  • GENBANK/AF113616