Transcription factor that plays a key role in male sex determination and differentiation by controlling testis development and germ cell proliferation. Acts both as a transcription repressor and activator. Testis-specific. Localizes to Sertoli cells. Expression starts at the neurula stage and persists during embryogenesis and larval stages until adulthood. At hatching and 5 days after hatching, present in XY embryos, but not in XX embryos. Detected only in the somatic cells surrounding germ cells in XY embryos. Feminization of XY offsprings. Belongs to the DMRT family.