Selective binding of the estrogen receptor to one strand of the estrogen responsive element.

The human estrogen receptor (hER) activates gene transcription by binding to cognate palindromic sequences called estrogen responsive elements (ERE). I used gel retardation assays and oligonucleotides containing the ERE from the Xenopus vitellogenin gene to study the interaction of the hER with the ERE. I observed that the hER bound to double-stranded ERE and to the single strand of the ERE that had T in the center with nearly equal affinity, but not to the strand which had A in the center. Interchanging the two central nucleotides changed the strand specificity. Binding of the hER to a single strand is extremely sensitive to temperature. Initial recognition of one of the two strands of the ERE may be involved in the binding of the hER to the ERE.