Cloning and characterization of the functional promoter of mouse estrogen receptor beta gene

The recently discovered estrogen receptor beta (ERbeta) exhibits some properties distinct from those of the classical estrogen receptor, ERalpha. To elucidate the mechanism underlying the regulation of ERbeta gene expression, we cloned and characterized the 5'-flanking (promoter) region of the mouse ERbeta (mERbeta) gene. A TATA-like motif was found in the 5'-flanking region, and transcription initiation sites were mapped 24 bp and 27 bp downstream from the motif by primer extension analysis and 5'-rapid amplification of cDNA ends. The mERbeta promoter contains several putative cis-acting elements, many of which are also found in the mouse ERalpha promoter. Therefore, the expression of both ERs may be partially regulated by a common mechanism. Luciferase assays revealed that the mERbeta promoter activity paralleled the endogenous expression levels of mERbeta in several cell lines. Successive 5'-deletion analyses showed that element(s) critical for its basal activity and negative regulatory element(s) are located in the sequences -90/+33 and -505/-372, respectively. The characterization of the mERbeta promoter will allow further studies to investigate the transcriptional regulation of mERbeta.