Transcriptional activity of testis-determining factor SRY is modulated by the Wilms’ tumor 1 gene product, WT1

The Wilms' tumor 1 (WT1) and sex-determining region of the Y chromosome (SRY) genes are essential for development of the mammalian gonads and mutations in these genes are associated with gonadal dysgenesis in humans. The SRY gene encodes a transcription factor with one high-mobility group (HMG) box as a DNA-binding domain. WT1 encodes a transcription factor that contains four contiguous C2H2-type zinc-finger motifs as a DNA/RNA binding or protein–protein interaction domain. Here we report that WT1 binds to and acts synergistically with SRY to activate transcription from a promoter containing SRY-binding sites. This interaction is mediated by the WT1 zinc-finger domain and the SRY HMG box. WT1 mutants associated with Denys–Drash syndrome (DDS), which is characterized by Wilms’ tumor, pseudohermaphroditism, and nephropathy, fail to interact with SRY. Wildtype WT1 is recruited to SRY-binding sites in an SRY-dependent manner, whereas DDS mutants are not recruited as efficiently. These results suggest that WT1 forms a complex with SRY to regulate transcription and that this WT1-SRY interaction is important in testis development.