Homeobox genes are a class of developmental regulatory genes that encode homeoproteins. Homeoproteins function as transcription factors to regulate downstream targets, turning on (activating) or turning off (repressing) other genes that in turn regulate developmental processes. Aberrant expression of homeobox genes has been implicated as causal factors in leukemia and solid tumors.
Homeobox genes are often referred to as master control genes. They are active during embryonic development and regulate important processes such as morphogenesis and cellular differentiation. They were first identified in Drosophila as the homeotic cluster (HOM-C) genes and were later found to have homologues in many species. They are now known to be highly evolutionarily conserved and are present in animals, plants, and fungi.
Homeobox genes share a common sequence motif (the homeobox), which is 180 nucleotides in length and encodes a 60 amino acid region (the homeodomain). The...