Open AccessMolecular cloning of a gene belonging to the carcinoembryonic antigen gene family and discussion of a domain model.
Author(s) -
John A. Thompson,
Hema Pande,
Raymond J. Paxton,
Louise Shively,
A. Padma,
Robert L. Simmer,
Charles W. Todd,
Arthur D. Riggs,
John E. Shively
Publication year - 1987
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.84.9.2965
Subject(s) - microbiology and biotechnology , gene , biology , carcinoembryonic antigen , complementary dna , exon , nucleic acid sequence , genetics , clone (java method) , southern blot , ecori , molecular cloning , coding region , restriction enzyme , cancer
Carcinoembryonic antigen (CEA) is a glycoprotein important as a tumor marker for colonic cancer. Immunological and biochemical studies have shown it to be closely related to a number of other glycoproteins, which together make up a gene family. We have cloned a member of this gene family by using long oligonucleotide probes (42-54 nucleotides) based on our protein sequence data for CEA and NCA (nonspecific cross-reacting antigen) and on human codon usage. The clone obtained (lambda 39.2) hybridizes with six probes and has a 15-kilobase insert. The 5' end of the gene is contained within a 2700-base-pair EcoRI fragment, which hybridizes with five of the six synthetic probes. Sequencing of the 5' end region revealed the location and structure of one exon and two putative intron boundaries. The exon encodes part of the leader sequence and the NH2-terminal 107 amino acids of NCA. Southern blot analysis of human normal and tumor DNA, using as probes two lambda 39.2 fragments that contain coding sequences, suggests the existence of 9-11 genes for the CEA family. One of the restriction fragments described here has been used by Zimmermann et al. [Zimmermann, W., Ortlieb, B., Friedrich, R. & von Kleist, S. (1987) Proc. Natl. Acad. Sci. USA 84, 2960-2964] to isolate partial cDNA clones for CEA. The identity of this clone was verified with our protein sequence data [Paxton, R., Mooser, G., Pande, H., Lee, T.D. & Shively, J.E. (1987) Proc. Natl. Acad. Sci. USA 84, 920-924]. We discuss a domain structure for CEA based on the CEA sequence data and the NCA exon sequence data. It is likely that this gene family evolved from a common ancestor shared with neural cell adhesion molecule and alpha 1 B-glycoprotein and is perhaps a family within the immunoglobulin superfamily.