The glucocorticoid receptor hormone binding domain mediates transcriptional activation in vitro in the absence of ligand.
We show that recombinant rat glucocorticoid receptor (vvGR) expressed using vaccinia virus is indistinguishable from authentic GR with respect to DNA and hormone binding. In the absence of hormone, vvGR is mainly found in the cytoplasm in a complex with heat shock protein 90. Upon incubation with ligand, vvGR is released from this complex and translocated to the nucleus. Thus, the ligand binding domain displays the known biochemical properties. However, in vitro, transcription from a synthetic promoter and from the mouse mammary tumor virus (MMTV) promoter is enhanced by recombinant GR in a ligand independent manner. Both transactivation domains contribute to the transcriptional activity, additively on a synthetic promoter and cooperatively on the MMTV promoter. We thus provide the first evidence that in vitro the hormone binding domain has a transcriptional activity even in the absence of ligand.
European Molecular Biology Laboratory, Gene Expression Programme, Heidelberg, Germany.
J
J
Schmitt
H G
HG
Stunnenberg
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D013698:Templates, Genetic; D014158:Transcription, Genetic; D014162:Transfection; D014222:Triamcinolone Acetonide / Q000378:metabolism*; D014616:Vaccinia virus / Q000235:genetics
D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D011965:Receptors, Glucocorticoid; D011994:Recombinant Proteins; D014222:Triamcinolone Acetonide