Estrogen receptor binds to the salmon GnRH gene in a region with long palindromic sequences

Footprinting and gel shift assays demonstrated that the human estrogen receptor (hER) specifically binds to two estrogen response element (ERE)-like motifs in the gonadotropin releasing hormone (GnRH) gene promoter region of Atlantic salmon (Salmo salar). The two ER binding sites are situated approximately 1.5 kb upstream of the transcriptional start site of the GnRH gene and are localized 49 bp from each other. Each ERE-like motif is composed of two palindromic ERE half-sites interspaced by 8 and 9 nucleotides, respectively. The salmon GnRH gene promoter region contains an almost perfect 426-bp-long palindromic sequence that might form a cruciform structure.