Molecular cloning and expression of human tumor-associated polymorphic epithelial mucin.
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.
Imperial Cancer Research Fund, Lincoln's Inn Fields, London, United Kingdom.
S J
SJ
Gendler
C A
CA
Lancaster
J
J
Taylor-Papadimitriou
T
T
Duhig
N
N
Peat
J
J
Burchell
L
L
Pemberton
E N
EN
Lalani
D
D
Wilson
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004848:Epithelium / Q000378:metabolism; D000939:Epitopes / Q000032:analysis; D015698:Genomic Library; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D018396:Mucin-1; D009077:Mucins / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics*; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D021382:Protein Sorting Signals / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping
D000911:Antibodies, Monoclonal; D000939:Epitopes; D008562:Membrane Glycoproteins; D018396:Mucin-1; D009077:Mucins; D015345:Oligonucleotide Probes; D021382:Protein Sorting Signals