Long-range transcriptional control of progesterone receptor gene expression.

Estrogen receptor alpha (ERalpha) binds to specific target DNA sequences, estrogen response elements (EREs), to regulate estrogen-responsive gene expression. The progesterone receptor (PR) gene has been used extensively as a marker of estrogen responsiveness. Although we previously identified cis elements within 1 kb of the PR-B transcription start site that are associated with ERalpha and help to confer estrogen responsiveness, the identification of ERalpha binding sites far removed from the transcription start site suggested that long-range regulation of this gene may occur.