Molecular cloning and expression of human Tumor-associated Polymorphic Epithelial Mucin
Pathology and Microbiology
Human mammary cells present on the cell surface a polymorphic epithelial mucin (PEM) which is developmentally regulated and aberrantly expressed in tumors. PEM carries tumor-associated epitopes recognized by the monoclonal antibodies HMFG-1, HMFG-2, and SM-3. Previously isolated partial cDNA clones revealed that the core protein contained a large domain consisting of variable numbers of 20-amino acid repeat units. We now report the full sequence for PEM, as deduced from cDNA sequences. The encoded protein consists of three distinct regions: the amino terminus consisting of a putative signal peptide and degenerate repeats; the major portion of the protein which is the tandem repeat region; the carboxyl terminus consisting of degenerate tandem repeats and a unique sequence containing a transmembrane sequence and a cytoplasmic tail. Potential O-glycosylation sites (serines or threonines) make up more than one-fourth of the amino acids. Length variations in the tandem repeat result in PEM being an expressed variable number tandem repeat locus. Tandem repeats appear to be a general characteristic of mucin core proteins.
Journal of Biological Chemistry
J, G. S.,
A, L. C.,
J, T. P.,
(1990). Molecular cloning and expression of human Tumor-associated Polymorphic Epithelial Mucin. Journal of Biological Chemistry, 265(25), 15286-15293.
Available at: http://ecommons.aku.edu/pakistan_fhs_mc_pathol_microbiol/423