Transcriptional Regulation of Aromatase in Placenta and Ovary

Our goal is to define the cellular and molecular mechanisms for tissue- and cell-specific, developmental and hormonal regulation of the human CYP19 (aromatase P450/P450arom) gene in estrogen-producing cells. In this article, we review studies using transgenic mice and transfected cells to identify genomic regions and response elements that mediate CYP19 expression in placenta and ovary, as well as to define the molecular mechanisms for O2 regulation of differentiation and CYP19 gene expression in human trophoblast cells in culture. We also highlight recent findings regarding LRH-1 versus SF-1 mRNA expression and cellular localization in the mouse ovary during the estrous cycle and various stages of pregnancy. Spatial and temporal expression patterns of mRNAs encoding these orphan nuclear receptors in comparison to those of P450arom and 17alpha-hydroxylase/17,20-lyase mRNAs, suggest an important role of LRH-1 together with SF-1 in ovarian steroidogenesis.