DNA-binding by Ig-fold proteins

Recent structures of the Runx1-CBF beta 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. Variation in the loop regions accounts for the diversity of DNA sequences recognized by Ig-fold proteins, but there are recurring themes in the interactions made by specific loop regions and how these interactions are regulated.