Insertion of metal-responsive elements increases the inducibility of the mouse mammary tumor virus promoter.
The promoter of the mouse mammary tumor virus (MMTV) is commonly used in inducible mammalian expression vectors. We have modified this promoter by inserting metal-responsive elements (MRE) at different sites. Surprisingly, MMTV promoters containing MRE 5' with respect to the glucocorticoid responsive elements (GRE), were not induced by metal ions. However, in the simultaneous presence of dexamethasone and metal ions, the modified promoters displayed a significantly increased transcriptional strength [up to sevenfold more than wild-type (wt) MMTV] in transiently transfected cells and permanent cell lines. This increment in the inducible expression was achieved without a concomitant increase in the basal level of expression. These modified MMTV promoters will offer the opportunity to develop tightly regulated inducible mammalian expression systems that are significantly more potent than the ones based on the wt MMTV promoter.
Yang
H
H
Department of Medical Biophysics, University of Toronto, Ontario, Canada.
Filmus
J
J
D000818:Animals; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000235:genetics*; D005822:Genetic Vectors / Q000235:genetics; D005938:Glucocorticoids / Q000235:genetics / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D008670:Metals / Q000494:pharmacology*; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics*; D051381:Rats; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection / Q000235:genetics; D014709:Vero Cells
D005938:Glucocorticoids; D008670:Metals; D003907:Dexamethasone; D015500:Chloramphenicol O-Acetyltransferase