The Core Binding Factors (CBFs) are a family of heterodimeric transcription factors which contain one of three different DNA binding α-subunits (Runx1-3) and a common-β-subunit, CBF. The α-subunits share a conserved region of 128 amino acids, known as the Runt domain, that mediates both DNA binding and heterodimerization to the β-subunit.
The heterodimeric complex between AML1 and CBF has an essential role in hematopoiesis and is the most frequent target for chromosomal rearrangements in acute human leukaemias. The structure of the AML1-CBFβ-DNA ternary complex has been determined . The structure explains the molecular basis for the loss of DNA binding function of the Runt domain-CBF β complex as a consequence of the human disease-associated mutations in leukaemogenesis.