A novel drug-regulated gene expression system based on the nuclear receptor constitutive androstane receptor (CAR).
OBJECTIVE
To develop and characterize a new drug-regulated gene expression system based on the nuclear receptor constitutive androstane receptor (CAR).


METHODS
Both transient and stable transfection into HEK293 cells of luciferase plasmids under the control of either drug- and steroid-responsive nuclear receptor CAR or the tetracycline-sensitive transactivator tTA were used in development of stable cell lines.


RESULTS
A stable first-generation cell line that expresses luciferase gene under the control of nuclear receptor CAR was developed. The luciferase expression in CAR-producing cells could be suppressed by androstanes and reactivated by structurally unrelated drugs chlorpromazine, metyrapone, phenobarbital, and clotrimazole. The kinetics of luciferase expression in CAR-producing cells and the tTA system were comparable. The overall regulation of CAR system was improved by modifications to the DNA binding domain and site.


CONCLUSIONS
Because of its wide ligand selectivity and transferable ligand binding domain, CAR expands the repertoire of regulated gene expression systems.
Honkakoski
P
P
Department of Pharmaceutics, University of Kuopio, Finland. paavo.honkakoski@uku.fi
Jääskeläinen
I
I
Kortelahti
M
M
Urtti
A
A
D000737:Androstenols / Q000494:pharmacology; D001665:Binding Sites; D001709:Biotechnology / Q000379:methods*; D002478:Cells, Cultured; D000090702:Constitutive Androstane Receptor; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D006801:Humans; D008024:Ligands; D008156:Luciferases / Q000235:genetics; D011725:Pyridines / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D000737:Androstenols; D000090702:Constitutive Androstane Receptor; D008024:Ligands; D011725:Pyridines; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; C028474:1,4-bis(2-(3,5-dichloropyridyloxy))benzene; D004247:DNA; D008156:Luciferases