Transcription factor which plays a key role in limb development. Positively regulates FGF8 expression in the apical ectodermal ridge (AER) and contributes to limb outgrowth in embryos. Detected in the forebrain, prospective midbrain/hindbrain boundary, tail bud, and neural keel and neural tube in the somitogenesis stages. Expressed in the pectoral fin bud, and the signal is restricted to the apical fold. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors. Belongs to the Sp1 C2H2-type zinc-finger protein family.