title: Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells.
abstract: We constructed a series of recombinant genomes which directed expression of the enzyme chloramphenicol acetyltransferase (CAT) in mammalian cells. The prototype recombinant in this series, pSV2-cat, consisted of the beta-lactamase gene and origin of replication from pBR322 coupled to a simian virus 40 (SV40) early transcription region into which CAT coding sequences were inserted. Readily measured levels of CAT accumulated within 48 h after the introduction of pSV2-cat DNA into African green monkey kidney CV-1 cells. Because endogenous CAT activity is not present in CV-1 or other mammalian cells, and because rapid, sensitive assays for CAT activity are available, these recombinants provided a uniquely convenient system for monitoring the expression of foreign DNAs in tissue culture cells. To demonstrate the usefulness of this system, we constructed derivatives of pSV2-cat from which part or all of the SV40 promoter region was removed. Deletion of one copy of the 72-base-pair repeat sequence in the SV40 promoter caused no significant decrease in CAT synthesis in monkey kidney CV-1 cells; however, an additional deletion of 50 base pairs from the second copy of the repeats reduced CAT synthesis to 11% of its level in the wild type. We also constructed a recombinant, pSV0-cat, in which the entire SV40 promoter region was removed and a unique HindIII site was substituted for the insertion of other promoter sequences.
mesh_terms: D000123:Acetyltransferases / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular / Q000379:methods; D004274:DNA, Recombinant; D005786:Gene Expression Regulation; D007668:Kidney; D009876:Operon; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004274:DNA, Recombinant; D000123:Acetyltransferases; D015500:Chloramphenicol O-Acetyltransferase