title: Stable, high-level expression of a carcinoembryonic antigen-encoding cDNA after transfection and amplification with the dominant and selectable asparagine synthetase marker.
abstract: The introduction and expression of cloned genes in a wide variety of animal cells requires the convenient use of dominant selectable markers. Very few of these markers can be amplified in copy number, a necessary feature if variable and high-level expression of the gene of interest is required. We describe the successful dominant transfection and amplification of a vector containing the Escherichia coli asparagine synthetase (AS)-encoding gene, asnA, transfected into a variety of human and rodent cell lines. An unlinked co-transfected expression vector containing the CEA cDNA, encoding human carcinoembryonic antigen, can be co-amplified with the asnA marker leading to extremely high levels of CEA synthesis. In addition, we show that the expression of both the asnA marker and the co-transfected CEA construct are stable in normal and amplified transfectants after prolonged culture in the absence of selective pressure.
authors.affiliation: Cancer Centre and Biochemistry Department, McGill University, Montréal, Québec, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Cartier
authors.forename: C P
authors.initials: CP
authors.lastname: Stanners
mesh_terms: D000818:Animals; D001217:Aspartate-Ammonia Ligase / Q000235:genetics* / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005784:Gene Amplification; D015870:Gene Expression; D005798:Genes, Bacterial; D005819:Genetic Markers; D006801:Humans; D014162:Transfection
chemical_list: D002272:Carcinoembryonic Antigen; D005819:Genetic Markers; D001217:Aspartate-Ammonia Ligase