Binds to GT and GC boxes promoters elements. Probable transcriptional activator. Required for normal male reproductive behavior. Expressed in many tissues. Highly expressed in embryos in the developing central nervous system (CNS). Expression is seen as early as day 9 of development, where transcripts are abundant in the posterior neuropore. Expression in later embryos is detected throughout the CNS as well as in other structures. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors. In SP4, the motif is inactive. Belongs to the Sp1 C2H2-type zinc-finger protein family.