Identification of NR5A1 (SF-1/AD4BP) gene expression modulators by large-scale gain and loss of function studies

Nuclear receptor subfamily 5, group A, member 1 (NR5A1 previously known as SF-1/AD4BP) is a transcription factor involved in the development of adrenal/gonadal tissues and steroidogenic linage cell differentiation in adult somatic stem cells. To understand the cellular signaling network that regulates NR5A 1 gene expression, loss of function screening with an siRNA kinome library, and gain of function screening with an addressable full-length cDNA library representing one quarter of the human genome was carried out. The NR5A1 gene expression was activated in mesenchymal stem cells by siRNA directed against protein kinase C (PKC)-o, erb-B3, RhoGAP (ARHGAP26), and hexokinase 2, none of which were previously known to be involved in the NR5A1 gene expression. Among these, we identified crosstalk between erb-B3 and PKC-5 signaling cascades. In addition, the gain of function studies indicated that sex-determining region Y (SRY)-box 15 (SOX15), TEA domain family member 4, KIAA1257 (a gene of unknown function), ADAM metallopeptidase with thrombospondin type 1 motif 6, Josephin domain containing 1, centromere protein, TATA box-binding protein-associated factor 5-like RNA polymerase, and inducible T-cell co-stimulator activate NR5A 1 gene expression. These results provide new insights into the molecular mechanisms of NR5A 1 gene expression.