Transcription factor which controls spermatogenesis and sperm cell fate by regulation of sperm gene expression. Localized along the length of most but not all of the autosomal pachytene chromosomes; not detected on X chromosome. Expressed in larval stage L3 male and hermaphrodite germlines, coinciding with sperm fate specification (at protein level) (PubMed:22570621). Expression persists throughout adulthood in males, but is absent in adult hermaphrodites that are undergoing oogenesis (at protein level) (PubMed:22570621).