Figure 1: Three-dimensional structure of the Runt domain and its interaction with the β subunit. Figure 4: Mapping of the β heterodimerization surface of the RD onto the three-dimensional structure.

Recent structures of the Runx1–CBFβ heterodimer bound to DNA brings to six the number of characterized eukaryotic transcription factor families that use an immunoglobulin (Ig) fold to bind to DNA.