Isolation and characterization of a cDNA encoding the KS1/4 epithelial carcinoma marker.
The mAb KS1/4 recognizes a novel cell surface glycoprotein on a variety of epithelial carcinomas which may be a useful target Ag for antibody-directed diagnostic and therapeutic approaches. Here we report the isolation and characterization of a full length cDNA clone coding for the KS1/4 Ag, as well as, physical and biochemical studies on the antigen derived from an adenocarcinoma of the lung cell line. Affinity purification of the KS1/4 Ag reveals three glycosylated species by NaDodSO4 PAGE with molecular weights of 42, 40, and 35 kDa. The 42- and 40-kDa species are similar at the protein level, differing by their degree of glycosylation, and the 35-kDa protein results from a dibasic proteolytic cleavage of the larger m.w. species. Although both the 42- and 40-kDa forms are found on the cell surface, the 40-kDa protein appears to be the predominant species. A cDNA clone containing the complete KS1/4 coding sequence and the 5'- and 3'-non-translated regions was isolated from a library constructed from the human adenocarcinoma of the lung derived cell line, UCLA-P3. The cDNA clone contains an open reading frame of 314 amino acids which includes a putative signal sequence of 23 amino acids. Northern blot analysis shows a single RNA species of 1.5-kb. Sequence analysis of the 5' and 3' noncoding regions of the KS1/4 cDNA revealed homologies to known proto-oncogenes and inflammatory mediators.
Perez
M S
MS
Scripps Clinic and Research Foundation, Department of Immunology, La Jolla, CA 92037.
Walker
L E
LE
D000230:Adenocarcinoma / Q000032:analysis / Q000235:genetics; D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000302:isolation & purification; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification*; D004274:DNA, Recombinant / Q000302:isolation & purification; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000302:isolation & purification; D011519:Proto-Oncogenes; D012313:RNA / Q000302:isolation & purification
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D004274:DNA, Recombinant; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D012313:RNA; D004247:DNA