Cloning and characterization of the 5′-flanking region of the rat estrogen receptor β gene

In the rat, estrogen receptor (ER) P is preferentially expressed in the ovary and the prostate gland where it is transcriptionally regulated by testosterone. A single 5'-end of rERP cDNA was identified in these tissues by the Y-RACE analysis in the present study. The transcription starting site was predicted at -335 from the translation starting signal (ATG), and a 640 bp section of the 5'-flanking region of the gene was cloned. Luciferase reporter assays revealed this region to be responsible for cell-specific promoter activity and successive deletion analyses indicated that only 98 bp were sufficient for basic promoter activity as well as for testosterone-dependent transcription. The sequence of the determined region found to demonstrate high homology with the mouse ER beta promoter with more than 80% identity between positions -1 and -550. The rat region of -30/-110 also showed good homology with 69% identity to corresponding section of the human promoter. Putative cis-acting elements, USF/Arnt and AML1a, were found in common in the promoter regions of three species. The present study thus demonstrated the 5'-flanking region of the rERP gene to be a functional promoter. (c) 2004 Elsevier Ltd. All rights reserved.