Homeo Domain
Grouping transcription factors (TFs) by structural domain has been extremely useful. In some instances the DNA-binding domain provides clues to their function. Homeodomain-containing TFs (>250 discovered) are often associated with developmental processes, and those in the interferon regulatory factor family are generally associated with triggering immune responses against viral infections The homeodomain in DNA is defined by a 180 bp homeobox region encoding a helix–turn–helix DNA-binding[1]. Nkx2.5 is an important member of the family of homeobox-containing TFs. This transcription factor functions in heart formation and development. Mutations in this gene cause atrial septal defect with atrioventricular conduction defect, and also tetralogy of Fallot, which are both heart malformation diseases[2].
[1] S. Banerjee-Basu et al. Molecular evolution of the homeodomain family of transcription factors. Nucleic Acids Res. 2001 August 1; 29(15): 3258–3269.
[2] Y. Zhang et al. GATA and Nkx factors synergistically regulate tissue-specific gene expression and development in vivo. Development. 2007 Jan;134(1):189-98.