Isolation and characterization of cDNA clones encoding the human carcinoembryonic antigen reveal a highly conserved repeating structure

摘要: Abstract For the isolation of cDNA clones encoding carcinoembryonic antigen (CEA), we have constructed a library from human colon tumor mRNA. The was screened with various oligonucleotides whose sequence had been deduced partial amino acid data for CEA. Positive candidate were hybridized probe repetitive DNA, because CEA mRNA contains an Alu element, and fragment genomic clone nonspecific cross-reacting antigen, closely related to Here report nucleotide two overlapping comprising 1422 nucleotides This encodes 372 COOH-terminal acids followed by 305 3' untranslated containing truncated repeat. predicted protein is composed repeats 178 acids, each exceptionally high homology 67%. Each repeat unit four conserved cysteine residues six nine putative N-glycosylation sites. most strongly expressed in primary tumors and, lesser extent, normal colonic tissue. No found HeLa cells fibroblasts.