Homeobox gene

Homeodomain
The Antennapedia homeodomain protein from Drosophila melanogaster bound to a fragment of DNA. The recognition helix and unstructured N-terminus are bound in the major and minor grooves respectively.
Identifiers
Symbol	Homeodomain
Pfam	PF00046
Pfam clan	CL0123
InterPro	IPR001356
SMART	SM00389
PROSITE	PDOC00027
SCOP	1ahd
SUPERFAMILY	1ahd
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

A homeobox is a DNA sequence, around 180 base pairs long, found within genes that are involved in the regulation of patterns of anatomical development (morphogenesis) in animals, fungi and plants. These genes encode homeodomain protein products that are transcription factors sharing a characteristic protein fold structure that binds DNA. The "homeo-" prefix in the words "homeobox" and "homeodomain" stems from the mutational phenotype known as "homeosis", which is frequently observed when these genes are mutated in animals. Homeosis is a term coined by William Bateson to describe the outright replacement of a discrete body part with another body part. Homeobox genes are not only found in animals, but have also been found in fungi, for example the unicellular yeasts, in plants, and numerous single cell eukaryotes .

Homeoboxes were discovered independently in 1983 by , Michael Levine, and William McGinnis working in the lab of Walter Jakob Gehring at the University of Basel, Switzerland; and by Matthew P. Scott and Amy Weiner, who were then working with Thomas Kaufman at Indiana University in Bloomington. The existence of homeobox genes were first discovered in Drosophila, where mutations in homeobox genes caused the radical alterations known as "homeotic transformations". One of the most famous such mutation is antennapedia, in which legs grow from the head of a fly instead of the expected antennae.