Estrogen receptor‐alpha (ER‐α) suppresses expression of its variant ER‐α36

Abstract

Recently, we identified and cloned a membrane-based estrogen receptor (ER), ER-alpha 36, which is transcribed from a previously unidentified promoter in the first intron of the original ER-alpha gene. We cloned the 5' flanking region of ER-alpha 36 and found the cloned DNA sequence possessed strong promoter activity. A single transcription initiation site was mapped and a number of putative regulatory elements for various transcription factors such as the Wilms' tumor suppressor, WT1 and estrogen receptor (ER) were identified in this region. Transient co-transfection experiments further demonstrated that ER-alpha suppresses ER-alpha 36 promoter activity in an estrogen-independent manner, which can be released by ER-alpha 36 itself.