title: lac repressor can regulate expression from a hybrid SV40 early promoter containing a lac operator in animal cells.
abstract: The E. coli lac operator and repressor were adapted for function in mammalian cells. Plasmids containing an SV40 early region (pSVlacO) or a chloramphenicol acetyl transferase gene (pSVlacOCAT) linked to a hybrid SV40 early promoter bearing a lac operator were tested for function. Identical plasmids lacking an operator (pX-8 and pX-8CAT) were controls. In vitro, early transcription from pSVlacO, but not from pX-8, was inhibited by lac repressor, and repression was overcome by IPTG. Repression of large T synthesis or CAT activity occurred in vivo only when the respective operator-containing plasmid was cotransfected with a plasmid encoding lac repressor, or when the recipient cells stably synthesized lac repressor. IPTG substantially relieved repression in both cases. CAT enzyme repression was paralleled by a decrease in CAT mRNA abundance. Thus regulatory elements of the lac operon function physiologically in mammalian cells.
mesh_terms: D000123:Acetyltransferases / Q000235:genetics; D000818:Animals; D015500:Chloramphenicol O-Acetyltransferase; D005822:Genetic Vectors; D007763:Lac Operon; D010957:Plasmids; D011401:Promoter Regions, Genetic; D051381:Rats; D012097:Repressor Proteins / Q000235:genetics*; D013539:Simian virus 40 / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D012097:Repressor Proteins; D014157:Transcription Factors; D000123:Acetyltransferases; D015500:Chloramphenicol O-Acetyltransferase