Abstract
The biological responses to steroid hormones are mediated by a family of ligand-inducible intracellular receptors that activate or repress transcription of target genes. Protein-protein interactions arc common among other transcriptional activators and may have important consequences for gene regulation by steroid hormone receptors. Using the mobility shift assay we have identified a factor that enhances specific DNA binding of truncated rat androgen (AR) and glucocorticoid (GR) receptors by 25-fold and 6-fold, respectively, through the formation of heteromeric complexes. This factor, designated receptor accessory factor, or RAF, also potentiates DNA binding of full-length human GR. RAF is temperature and trypsin sensitive and is present in a variety of cultured mammalian cells. By gel filtration RAF has a predicted molecular mass of 130 kDa. RAF enhancement of AR-DNA binding requires androgen response clement DNA. RAF appears to interact directly with AR because deoxycholate, which interferes with protein-protein but not protein-DNA interactions, prevents RAF-AR-DNA complex formation. Furthermore, RAF activity is recovered from an androgen response element DNA affinity column only in the presence of AR. Mutagenesis of truncated AR fragments indicates that a region in the NH2-terminal domain is required for RAF to enhance AR-DNA binding. The interaction of RAF with AR and GR suggests that RAF might influence the ability of these nuclear receptors to activate transcription.
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Kupfer, S., Marschke, K., Wilson, E. et al. RECEPTOR ACCESSORY FACTOR (RAF) ENHANCES SPECIFIC DNA BINDING OF ANDROGEN AND GLUCOCORTICOID RECEPTORS. Pediatr Res 33 (Suppl 5), S19 (1993). https://doi.org/10.1203/00006450-199305001-00097
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DOI: https://doi.org/10.1203/00006450-199305001-00097