Characterization of a cis‐acting regulatory element involved in human‐aromatase P‐450 gene expression

Abstract

The characteristics of a cis‐acting regulatory region involved in the human‐aromatase P‐450 gene have been examined by transient expression analysis. The region spans from −242 –−166 relative to the cap site of the gene. A fragment containing the region excised from the gene enhances heterologous promoter activity as well as its own promoter activity in a position‐independent and orientation‐independent manner. The fragment exerts its enhancer activity in human BeWo choriocarcinoma cells in which the aromatase P‐450 gene is expressed, but not in other cell lines tested. Deletion of 38 bp from the 3′ end of the fragment results in a complete loss of enhancer activity. A gel‐retardation assay with nuclear extracts from BeWo cells suggests the existence of a nuclear factor(s) which interacts with the fragment. These results suggest that the regulatory element in the fragment is involved in efficient transcription of the human‐aromatase P‐450 gene.