title: Identification and topology of variant sequences within individual repeat domains of the human epithelial tumor mucin MUC1.
abstract: This study shows for the first time that the tandemly repeated icosapeptide of human MUC1 underlies a genetic sequence polymorphism at three positions (underlined): PDTRPAPGSTAPPAHGVTSA. The concerted replacement DT-->ES (sequence variation 1) and the single replacements P-->Q (sequence variation 2), P-->A (sequence variation 3), and P-->T (sequence variation 4) were identified by sequencing of polymerase chain reaction products and studied by minisatellite variant repeat analysis for their incidence and topology in the 5' and 3' peripheral regions of the variable number of tandem repeats domain. Minisatellite variant repeat analyses were performed with 27 individual samples of genomic DNA from human cells and tissues covering 30-60% of the domain. Within the peripheral regions, sequence variations 1-4 occur at high incidence and show a nearly constant repeat topology in all individual normal and tumor samples. Also, individuals who were non-Caucasian or of different ethnic background were found to have the same set of replacements with identical topology. The repeat variant 1 replacing the established tumor target motif DTR with ESR was found in all individuals and appears predominantly in repeat clusters (diads and triads). The largely constant topology of variant repeats is interpreted by the assumption that the variable number of tandem repeats domain has evolved as a recent expansion of sequence variable super-repeats.
authors.affiliation: Institute of Biochemistry II, Medical Faculty, University of Cologne, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Engelmann
authors.forename: S E
authors.initials: SE
authors.lastname: Baldus
authors.forename: F G
authors.initials: FG
authors.lastname: Hanisch
mesh_terms: D000483:Alleles; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D001943:Breast Neoplasms / Q000378:metabolism; D005819:Genetic Markers; D014644:Genetic Variation; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D018396:Mucin-1 / Q000737:chemistry* / Q000235:genetics*; D009375:Neoplasms, Glandular and Epithelial / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary; D020449:Repetitive Sequences, Amino Acid; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured
chemical_list: D005819:Genetic Markers; D018396:Mucin-1; D010455:Peptides