Roles of estrogen receptor α (ERα) in the regulation of the human Müllerian inhibitory substance (MIS) promoter

Sex differentiation consists of multi-step pathway that involves expression of many different genes. Müllerian duct inhibitory substance (MIS) has a key role for regression of the Müllerian duct during male sex differentiation. Recently, endocrine disruptors (EDs), which often have estrogen-like activities, have caused concern over worldwide. It has been reported that estrogen regulates the MIS expression. Therefore, we tested whether ERαand ERβinfluence the MIS promoter activity in the NT2/D1 cell line which expresses many sex differentiation related genes such as SRY, SOX9, and DAX-1. RT-PCR analysis revealed that the NT2/D1 cells express bother ERβ in addition to MIS. Under the low concentration of 17β-estradiol (E2), the over-expression of exogenous ERα increased the MIS promoter activity 3.3-fold compared with the control. However, as E2 concentration was increased, the MIS promoter activity was decreased. For ERβ, we could not observe alterations of the MIS promoter activity. Furthermore, the over-expression of the exogenous SF-1 inhibited the activation of the MIS promoter with ERα. Although it remains unclear whether the effects of ERαon the MIS promoter are mediated through the genomic or the no-genomic actions, the present results suggest that ERα upregulates the MIS promoter activity in the NT2/D1 cells under low concentrations of E2, and that the two ERs may work in different manners for the MIS promoter activation. The present findings may be useful to understand the molecular mechanisms by which EDs or estrogens affect the MIS expression.