The retinoid X receptor response element in the human aldehyde dehydrogenase 2 promoter is antagonized by the chicken ovalbumin upstream promoter family of orphan receptors

Two tandem sites in the aldehyde dehydrogenase 2 promoter (designated FP330 -5' and FP330-3') that bind members of the nuclear receptor superfamily mer e recently identified. Antibodies against apolipoprotein regulatory protein (ARP-1) altered DNA-protein interactions in electrophoretic mobility shift assays using oligonucleotides representing either promoter site and rat li ver or cultured cell nuclear extracts. In vitro-translated chicken ovalbumi n upstream promoter transcription factor (COUP-TFI), ARP-1, or EfbA-related protein 2 (Ear2) bound both sites. In addition, ARP-1/RXR, COUP-TFI/RXR, a nd ARP-1/COUP-TFI heterodimers bound the FP330-3' site. Mutagenesis of the FP330-3' site indicated that a DR-1 element was the preferred binding site for these factors. Transfected expression plasmids for these factors suppre ssed basal expression of reporter constructs containing the FP330-3' sites and the induction of the reporter by RXR alpha plus retinoic acid. Mutation of the two sites increased activity of a construct driven by 600 bp of the ALDH2 promoter in cell lines expressing COUP-TFs. The ALDH2 FP330-3' site appears to represent a complex nuclear receptor response element that is ac tivated by RXRs and HNF-4 but repressed by members of the COUP-TF family. ( C) 2000 Academic Press.