SF-1, a nuclear receptor that regulates gene expression of the cytochrome P450 steroid hydroxylases, and ELP, an embryonal protein that suppresses expression of the Moloney murine leukemia virus LTR, are isoforms transcribed from the same gene by alternative promoter usage and splicing. This gene is the mammalian homolog of the Drosophila fushi-tarazu factor 1 (FTZ-F1) gene. We have mapped the mouse gene Ftzf1 to the proximal quarter of Chr 2 by a linkage analysis using interspecific backcross mice, and its human homolog FTZ1 to Chr 9q33 by fluorescence in situ hybridization. The mouse and human genes are located in the homologous regions of mouse Chr 2 and human Chr 9, respectively.
