The estrogen receptor-related receptorc (ERRc/ERR3/ NR3B3) is an orphan member of the nuclear receptor superfamily closely related to the estrogen receptors. To explore the DNA binding characteristics, the protein–DNA interaction was studied in electrophoretic mobility shift assays (EMSAs). In vitro translated ERRc binds as a homodimer to direct repeats (DR) without spacing of the nuclear receptor half-site 5¢-AGGTCA-3¢(DR-0), to exten-dedhalf-sites, and to the inverted estrogen response element