Expression of the gonadal p450 aromatase gene of Xenopus and characterization of the 5′-flanking region of the aromatase gene

Investigation by RQ-RT-PCR revealed that transcription of the p450 aromatase gene is activated at stage 50, when sex determination of the female begins, and that aromatase gene expression is also activated by exogenously administrated estradiol. In order to determine the molecular basis underlying the specific activation of aromatase gene expression during sex differentiation and in response to exogenous estradiol, we isolated the 5′-flanking fragment of the gene and characterized the promoter sequence. We demonstrated binding sequences to a specific trans-activating factor upstream of the p450 aromatase promoter II, the cAMP response element binding protein/activating transcription factor family, and steroidogenic factor-1. An estrogen response element half-site sequence that recognize an estrogen receptors, was also found.