Résumé
Estrogen receptor-related receptor α (ERRα) is an orphan nuclear receptor closely related to the estrogen receptor (ER), whose expression covers various stages of embryonic development and persists in certain adult tissues. We show that ERRα binds as a homodimer on a specific target sequence, the SFRE (SF-1 response element), already known to respond to the orphan nuclear receptor SF-1. Target sequences that are related to the SFRE and that discriminate between ERRα and SF-1 were identified. We have also analyzed the transcriptional properties of the ERRα originating from various species. All ERRα orthologs act as potent transactivators through the consensus SFRE. ERRα activity depends on the putative AF2AD domain, as well as on a serum compound that is withdrawn by charcoal treatment, suggesting the existence of a critical regulating factor brought by serum.