Mucins repeating amino acid sequences

Mucins Have a High Content of O-Linked Oligosaccharides Exhibit Repeating Amino Acid Sequences... 

CA 27.29 is detected by a monoclonal antibody, B27.29, that is produced against an antigen in ascites of patients with metastatic breast carcinoma. The minimum epitope to which B27.29 reacts is the 8 amino acid sequence (SAPDTRPA) within the 20 amino acid tandem repeating sequence of the mucin core. The reactive sequence of the B27.29 overlaps with the sequence of DF3 used in the CA 15-3 assay. In inhibition studies using labeled MAb, B27.29 effectively competes with DF3 for binding to both CA 27.29 and CA 15-3 antigens. "... 

Selected human transmembrane-bound (TM) mucins and secreted mucins are listed, including those that form a mucus gel (Gel). The highly O-glycosylated Ser/Thr/Pro-rich variable number of tandem repeats (VNTR) show a representative amino acid sequence in one of the repeats. The underlined sequence in MUCl is a peptide epitope recognized by anti-MUC1 antibody SM3. Some of the tissues expressing these mucins are listed but most mucins are widely expressed and found in many other tissues and cell types. 

The epitope recognized by the antibody DU-PAN-2 is a mucin. Its molecular mass is between 100 and 500kDa, and it is 80% carbohydrate. cDNA for the core protein has been cloned and sequenced, and the predicted amino add sequence reveals a protein of 126kDa containing 1295 amino acid residues with 42 tandem repeats. DU-PAN-2 antigen is found mainly in the glandular epitheiia of the pancreatic and biliary systems and in the breast and bronchial ducts. A lower level of expression is found in cells of the salivary glands, stomach, colon, and intestine. ... 

Burchell, J., Papadimitriou, J. T, Boshell, M., Gendler, S., and Duhig, T, 1989, A short sequence, within the amino acid tandem repeat of a cancer-associated mucin, contains immunodominant epitopes, Int. J. Cancer 44 691-696. 

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