Genomic organization and structure of the 3' region of human MUC3: alternative splicing predicts membrane-bound and soluble forms of the mucin.
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Crawley SC, Gum JR Jr, Hicks JW, Pratt WS, Aubert JP, Swallow DM, Kim YS
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.
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- 10512748 [ View in PubMed]
- Abstract
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.