Cell type specific regulation of COUP-TF II promoter activity

COUP-TF family orphan receptors regulate activity of ligand-activated nuclear hormone receptors or function independently in the regulation of gene expression. COUP-TF II has a complex expression pattern suggesting that different mechanisms are involved in the regulation of its expression. We isolated the 5' regulatory region of the mouse COUP-TF II gene and demonstrated that the basal promoter is localized in a -200 bp region 5' from the transcription start site. All-trans retinoic acid and dibutyryl cyclic AMP have cell type specific effects on COUP-TF II promoter activity. The effect of cyclic AMP is mediated by the cyclic AMP response element that is localized 74 nucleotides upstream from the major transcriptional start. In vitro promoter analyses also demonstrated that the effect of all-trans RA is not directly mediated by the binding of RARs or RXRs to the promoter sequence.