Ready-to-use ELISA kits are available for the detection of trans-acting transcription factor 3, an alias of the protein, Sp3 transcription factor. The official gene symbol is SP3. The protein, with a mass of 81.9 kDa and length of 781 residues, is reported to be nuclear. It is a member of the Sp1 C2H2-type zinc-finger protein family and may be known by other names, including: SPR2, specificity protein 3, GC-binding transcription factor Sp3, and transcription factor Sp3.