Physical interaction and functional synergy between glucocorticoid receptor and Ets2 proteins for transcription activation of the rat cytochrome P-450c27 promoter.
We demonstrate that dexamethasone-mediated transcription activation of the cytochrome P-450c27 promoter involves a physical interaction and functional synergy between glucocorticoid receptor (GR) and Ets2 factor. Ets2 protein binding to a "weak" Ets-like site of the promoter is dependent on GR bound to the adjacent cryptic glucocorticoid response element. Coimmunoprecipitation and chemical cross-linking experiments show physical interaction between GR and Ets2 proteins. Mutational analyses show synergistic effects of Ets2 and GR in dexamethasone-mediated activation of the cytochrome P-450c27 promoter. The DNA-binding domain of GR, lacking the transcription activation and ligand-binding domains, was fully active in synergistic activation of the promoter with intact Ets2. The DNA-binding domain of Ets2 lacking the transcription activation domain showed a dominant negative effect on the transcription activity. Finally, a fusion protein consisting of the GR DNA-binding domain and the transcription activation domain of Ets2 fully supported the transcription activity, suggesting a novel synergy between the two proteins, which does not require the transactivation domain of GR. Our results also provide new insights on the role of putative weak consensus Ets sites in transcription activation, possibly through synergistic interaction with other gene-specific transcription activators.
Mullick
J
J
Department of Animal Biology, Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Anandatheerthavarada
H K
HK
Amuthan
G
G
Bhagwat
S V
SV
Biswas
G
G
Camasamudram
V
V
Bhat
N K
NK
Reddy
S E
SE
Rao
V
V
Avadhani
N G
NG
D016475:3T3 Cells; D000818:Animals; D053493:Cholestanetriol 26-Monooxygenase; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins; D051379:Mice; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins; D015398:Signal Transduction / Q000235:genetics; D013250:Steroid Hydroxylases / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; C107465:ERF protein, human; C494070:Ets2 protein, mouse; C494071:Ets2 protein, rat; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins; D011965:Receptors, Glucocorticoid; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; C506832:Cyp27a1 protein, mouse