THAP3 (THAP domain-containing protein 3) is a 239 amino acid protein that contains one THAP-type zinc finger and exists as three alternatively spliced isoforms. The gene that encodes THAP3 contains roughly 10,721 bases and maps to human chromosome 1p36.31. Spanning about 260 million base pairs and comprising nearly 8% of the human genome, chromosome 1 is the largest human chromosome.