Editing Homeobox (section)

{{Short description|DNA pattern affecting anatomy development}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Infobox protein family
| Symbol = Homeodomain
| Name = Homeodomain
| image = Homeodomain-dna-1ahd.png
| width = 
| caption = The [[Antennapedia]] homeodomain protein from ''[[Drosophila melanogaster]]'' bound to a fragment of [[DNA]].<ref name="pmid7903398">{{PDB|1AHD}}; {{cite journal | vauthors = Billeter M, Qian YQ, Otting G, Müller M, Gehring W, Wüthrich K | title = Determination of the nuclear magnetic resonance solution structure of an Antennapedia homeodomain-DNA complex | journal = Journal of Molecular Biology | volume = 234 | issue = 4 | pages = 1084–93 | date = December 1993 | pmid = 7903398 | doi = 10.1006/jmbi.1993.1661 }}</ref> The recognition helix and unstructured N-terminus are bound in the major and minor grooves respectively.
| Pfam = PF00046
| Pfam_clan = CL0123
| InterPro = IPR001356
| SMART = SM00389
| PROSITE = PDOC00027
| SCOP = 1ahd
| TCDB = 
| OPM family = 
| OPM protein = 
| PDB = {{PDB2|1ahd}}, {{PDB2|1akh}}, {{PDB2|1apl}}, {{PDB2|1au7}}, {{PDB2|1b72}}, {{PDB2|1b8i}}, {{PDB2|1bw5}}, {{PDB2|1cqt}}, {{PDB2|1du0}}, {{PDB2|1du6}}, {{PDB2|1e3o}}, {{PDB2|1enh}}, {{PDB2|1f43}}, {{PDB2|1fjl}}, {{PDB2|1ftt}}, {{PDB2|1ftz}}, {{PDB2|1gt0}}, {{PDB2|1hdd}}, {{PDB2|1hdp}}, {{PDB2|1hf0}}, {{PDB2|1hom}}, {{PDB2|1ic8}}, {{PDB2|1ig7}}, {{PDB2|1jgg}}, {{PDB2|1k61}}, {{PDB2|1kz2}}, {{PDB2|1le8}}, {{PDB2|1lfb}}, {{PDB2|1lfu}}, {{PDB2|1mh3}}, {{PDB2|1mh4}}, {{PDB2|1mnm}}, {{PDB2|1nk2}}, {{PDB2|1nk3}}, {{PDB2|1o4x}}, {{PDB2|1ocp}}, {{PDB2|1oct}}, {{PDB2|1p7i}}, {{PDB2|1p7j}}, {{PDB2|1pog}}, {{PDB2|1puf}}, {{PDB2|1qry}}, {{PDB2|1s7e}}, {{PDB2|1san}}, {{PDB2|1uhs}}, {{PDB2|1vnd}}, {{PDB2|1wi3}}, {{PDB2|1x2m}}, {{PDB2|1x2n}}, {{PDB2|1yrn}}, {{PDB2|1yz8}}, {{PDB2|1zq3}}, {{PDB2|1ztr}}, {{PDB2|2cqx}}, {{PDB2|2cra}}, {{PDB2|2cue}}, {{PDB2|2cuf}}, {{PDB2|2dmq}}, {{PDB2|2e1o}}, {{PDB2|2ecb}}, {{PDB2|2ecc}}, {{PDB2|2h8r}}, {{PDB2|2hdd}}, {{PDB2|2hi3}}, {{PDB2|2hoa}}, {{PDB2|2jwt}}, {{PDB2|2lfb}}, {{PDB2|2p81}}, {{PDB2|2r5y}}, {{PDB2|2r5z}}, {{PDB2|3hdd}}, {{PDB2|9ant}}
}}

A '''homeobox''' is a [[Nucleic acid sequence|DNA sequence]], around 180 [[base pair]]s long, that regulates large-scale anatomical features in the early stages of embryonic development.  Mutations in a homeobox may change large-scale anatomical features of the full-grown organism.

Homeoboxes are found within [[gene]]s that are involved in the regulation of patterns of anatomical development ([[morphogenesis]]) in [[animal]]s, [[fungus|fungi]], [[plant]]s, and numerous single cell [[eukaryote]]s.<ref name="pmid26464018"/> Homeobox genes encode '''homeodomain''' [[protein]] products that are [[transcription factor]]s sharing a characteristic [[protein fold]] structure that binds [[DNA]] to regulate expression of target genes.<ref name="PUB00005390">{{cite journal | vauthors = Gehring WJ | title = The homeobox in perspective | journal = Trends in Biochemical Sciences | volume = 17 | issue = 8 | pages = 277–80 | date = August 1992 | pmid = 1357790 | doi = 10.1016/0968-0004(92)90434-B }}</ref><ref name="pmid7903947">{{cite journal | vauthors = Gehring WJ | title = Exploring the homeobox | journal = Gene | volume = 135 | issue = 1–2 | pages = 215–21 | date = December 1993 | pmid = 7903947 | doi = 10.1016/0378-1119(93)90068-E }}</ref><ref name="pmid26464018">{{cite journal | vauthors = Bürglin TR, Affolter M | title = Homeodomain proteins: an update | journal = Chromosoma | volume = 125 | issue = 3 | pages = 497–521 | date = June 2016 | pmid = 26464018 | pmc = 4901127 | doi = 10.1007/s00412-015-0543-8 }}</ref> Homeodomain proteins regulate gene expression and cell differentiation during early embryonic development, thus mutations in homeobox genes can cause developmental disorders.<ref>{{cite web |title=Homeoboxes |url= https://ghr.nlm.nih.gov/primer/genefamily/homeoboxes |work = Genetics Home Reference | publisher = U.S. National Library of Medicine |language=en |access-date=2019-11-20 |archive-date=2019-12-21 |archive-url=https://web.archive.org/web/20191221100103/https://ghr.nlm.nih.gov/primer/genefamily/homeoboxes |url-status=dead }}</ref> 

[[Homeosis]] is a term coined by [[William Bateson]] to describe the outright replacement of a discrete body part with another body part, e.g. [[antennapedia]]—replacement of the antenna on the head of a fruit fly with legs.<ref>Materials for the study of variation, treated with especial regard to discontinuity in the origin of species William Bateson 1861–1926. London : Macmillan 1894 xv, 598 p</ref> The "homeo-" prefix in the words "homeobox" and "homeodomain" stems from this [[mutation|mutational phenotype]], which is observed when some of these genes are mutated in [[animals]]. The homeobox domain was first identified in a number of ''Drosophila'' [[Homeosis|homeotic]] and segmentation proteins, but is now known to be well-conserved in many other animals, including [[vertebrate]]s.<ref name="PUB00005390" /><ref name="PUB00005540">{{cite journal|author=Schofield PN|year=1987|title=Patterns, puzzles and paradigms - The riddle of the homeobox|journal=Trends Neurosci.|volume=10|pages=3–6|doi=10.1016/0166-2236(87)90113-5|s2cid=53188259}}</ref><ref name="PUB00000591">{{cite journal | vauthors = Scott MP, Tamkun JW, Hartzell GW | title = The structure and function of the homeodomain | journal = Biochimica et Biophysica Acta (BBA) - Reviews on Cancer | volume = 989 | issue = 1 | pages = 25–48 | date = July 1989 | pmid = 2568852 | doi = 10.1016/0304-419x(89)90033-4 }}</ref>