PROSITE documentation PDOC50803
OAR domain profile


This 14 amino acid motif has been identified within the C-terminal region of several Paired-like homeodomain (HD) (see <PDOC00027>) containing proteins [1,2]. It was named OAR domain after the initials of otp, aristaless, and rax [3].

Although it has been proposed that this domain could be important for transactivation and be involved in protein-protein interactions or DNA binding [3,4], its function is not yet known.

Some proteins known to contain an OAR domain are listed below:

  • Human RIEG. Defects in this protein are the cause of Rieger syndrome, an autosomal dominant disorder that includes anomalies of the anterior chamber of the eye, dental hypoplasia and a protuberant umbilicus [1].
  • Mammalian OG12X. The function of these proteins is not yet known [2].
  • Vertebrate Rax, encoded by the retina and anterior neural fold homeobox gene. This protein plays a role in the proliferation and/or differentiation of retinal cell [3].
  • Drosophila DRX. It could be a homolog of vertebrate Rax. It appears to be important in brain development [5].
  • Human SHOX, encoded by the short stature homeobox-containing gene. Defects or lack of this protein are the cause of short stature associated with the Turner syndrome [4].
  • Mammalian PITX3. This protein appears to be involved in normal eye anterior-chamber and lens development [6,7]. In human, defects in PITX3 are associated with anterior segment mesenchymal dysgenesis (ASMD) and autosomal-dominant congenital cataracts (ADCC) [7].
  • Vertebrate Pax3 and Pax7, transcription factors that play fundamental roles in the development of multi-cellular animals (Metazoa) [8].
  • Vertebrate visual system homeobox 2 (VSX2) [8].
  • Vertebrate dorsal root ganglia homeobox protein (DRG11) [8].

The OAR domain has also been called paired-type homeodomain tail (PHT), paired tail or C-peptide domain [8].

The profile we developed covers the entire OAR domain.

Last update:

April 2015 / Profile revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

OAR, PS50803; OAR domain profile  (MATRIX)


1AuthorsSemina E.V. Reiter R. Leysens N.J. Alward W.L.M. Small K.W. Datson N.A. Siegel-Bartelt J. Bierke-Nelson D. Bitoun P. Zabel B.U. Carey J.C. Murray J.C.
TitleCloning and characterization of a novel bicoid-related homeobox transcription factor gene, RIEG, involved in Rieger syndrome.
SourceNat. Genet. 14:392-399(1996).
PubMed ID8944018

2AuthorsSemina E.V. Reiter R.S. Murray J.C.
TitleA new human homeobox gene OGI2X is a member of the most conserved homeobox gene family and is expressed during heart development in mouse.
SourceHum. Mol. Genet. 7:415-422(1998).
PubMed ID9466998

3AuthorsFurukawa T. Kozak C.A. Cepko C.L.
Titlerax, a novel paired-type homeobox gene, shows expression in the anterior neural fold and developing retina.
SourceProc. Natl. Acad. Sci. U.S.A. 94:3088-3093(1997).
PubMed ID9096350

4AuthorsRao E. Weiss B. Fukami M. Rump A. Niesler B. Mertz A. Muroya K. Binder G. Kirsch S. Winkelmann M. Nordsiek G. Heinrich U. Breuning M.H. Ranke M.B. Rosenthal A. Ogata T. Rappold G.A.
TitlePseudoautosomal deletions encompassing a novel homeobox gene cause growth failure in idiopathic short stature and Turner syndrome.
SourceNat. Genet. 16:54-63(1997).
PubMed ID9140395

5AuthorsEggert T. Hauck B. Hildebrandt N. Gehring W.J. Walldorf U.
TitleIsolation of a Drosophila homolog of the vertebrate homeobox gene Rx and its possible role in brain and eye development.
SourceProc. Natl. Acad. Sci. U.S.A. 95:2343-2348(1998).
PubMed ID9482887

6AuthorsSemina E.V. Reiter R.S. Murray J.C.
TitleIsolation of a new homeobox gene belonging to the Pitx/Rieg family: expression during lens development and mapping to the aphakia region on mouse chromosome 19.
SourceHum. Mol. Genet. 6:2109-2116(1997).
PubMed ID9328475

7AuthorsSemina E.V. Ferrell R.E. Mintz-Hittner H.A. Bitoun P. Alward W.L.M. Reiter R.S. Funkhauser C. Daack-Hirsch S. Murray J.C.
TitleA novel homeobox gene PITX3 is mutated in families with autosomal-dominant cataracts and ASMD.
SourceNat. Genet. 19:167-170(1998).
PubMed ID9620774

8AuthorsVorobyov E. Horst J.
TitleGetting the proto-Pax by the tail.
SourceJ. Mol. Evol. 63:153-164(2006).
PubMed ID16830101

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