Forkhead Box Protein D1 (FOXD1)

The forkhead genes are transcription factors distinguished by a characteristic 100-amino acid motif that was originally identified in Drosophila . Northern blot analysis revealed that the FREAC4, or FKHL8, gene is expressed as a 2.1-kb mRNA exclusively in testis and kidney.The intronless gene predicts a protein of 465 amino acids with a hyperacidic N-terminal end, a DNA-binding forkhead domain, and a proline- and alanine-rich C-terminal end. The putative promoter region was active as a reporter fusion in the kidney-derived cell lines 293 and COS-7. Cotransfections with plasmids expressing WT1, WTAR (a mutated form of WT1), p53, and a mutated form of p53 revealed a complex pattern of regulation, suggesting that FREAC4 may be regulated by these gene products.