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Amplification and expression of recombinant genes in serum‐independent Chinese hamster ovary cells
Author(s) -
Christine R. Gandor,
C. Leist,
Armin Fiechter,
Fred A.M. Asselbergs
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01328-8
Subject(s) - chinese hamster ovary cell , dihydrofolate reductase , microbiology and biotechnology , gene , recombinant dna , activator (genetics) , gene expression , transfection , plasminogen activator , biology , cell culture , proteases , chemistry , biochemistry , enzyme , genetics
CHO SSF3 cells grow as a suspension culture in unmodified commercial medium with only low–molecular weight ingredients. Continuous serum–free culture unexpectedly induced expression of a low dihydrofolate reductase activity in the originally dhfr – CHO cells. Nevertheless, it was possible with methotrexate to induce amplification of a gene coding for the hybrid plasminogen activator K2tu–PA cotransfected with a dhfr gene. Expression of K2tu–PA expression was proportionally increased to that of dhfr , which was measured with fluorescent methotrexate. Because no serum proteases were present, secreted K2tu–PA was not converted to the enzymatically active form, but was exclusively recovered in proenzyme form.