Transcription factor that binds preferentially to the octamer motif (5'-ATGTTAAT-3'). May exert a regulatory function in meiotic events that are required for terminal differentiation of male germ cell (By similarity). Expressed in skeletal and cardiac muscles, brain, heart and lung. Little or no detectable expression found in pancreas, kidney, liver or placenta. Belongs to the POU transcription factor family. Class-5 subfamily.