Steroids act via nuclear receptors which interact with DNA through

Binding of transcription regulatory proteins to DNA is regulated by several motifs : Helix turn helix Leucine zipper Zinc finger Binding motif for steroid receptor family & thyroid (nuclear) receptor family is a zinc finger. In proteins with zinc - finger motif, the binding site is repeated 2-9 times. Proteins with helix-turn-helix and leucine zipper motifs form symmetrical palindromes and their DNA binding sites are symmetrical palindromes. In leucine - zipper motif, there is a periodic repeat of a leucine residue at every 7th position