The BTB (Broad-Complex, Tramtrack and Bric a brac) domain, also known as the POZ (POxvirus and Zinc finger) domain, is an N-terminal homodimerization domain that contains multiple copies of kelch repeats and/or C2H2-type zinc fingers. Proteins that contain BTB domains are thought to be involved in transcriptional regulation via control of chromatin structure and function. ZBTB3 (zinc finger and BTB domain containing 3) is a 574 amino acid protein that contains one BTB (POZ) domain and two C2H2-type zinc fingers. Localized to the nucleus, ZBTB3 is thought to play a role in transcriptional regulation events. The gene encoding ZBTB3 maps to human chromosome 11, which houses over 1,400 genes and comprises nearly 4% of the human genome.