The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

Irx4  -  Iroquois related homeobox 4 (Drosophila)

Mus musculus

Synonyms: Homeodomain protein IRXA3, Iroquois homeobox protein 4, Iroquois-class homeodomain protein IRX-4, Irxa3
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of Irx4


High impact information on Irx4

  • We conclude that Irx4 is not sufficient for ventricular chamber formation but is required for the establishment of some components of a ventricle-specific gene expression program [1].
  • To define the role of Irx4, a member of the Iroquois family of homeobox transcription factors in mammalian heart development and function, we disrupted the murine Irx4 gene [1].
  • Cardiac morphology in Irx4-deficient mice (designated Irx4(Delta ex2/Delta ex2)) was normal during embryogenesis and in early postnatal life [1].
  • Our molecular analyses also revealed the cooperative regulation of the homeodomain protein, Irx4, by Nkx2.5 and dHAND [2].
  • Throughout all subsequent stages in which the chambers of the heart become morphologically distinct (E8.5-11) and into adulthood, cardiac Irx4 expression is found exclusively in the ventricular myocardium [3].

Anatomical context of Irx4

  • Irx4 expression was observed in a segment of the linear heart tube and the atrioventricular canal and ventricular myocardium including the inner curvature after looping, resembling the pattern of MLC2V [4].
  • In mice at embryonic day (E) 7.5, Irx4 transcripts are found in the chorion and at low levels in a discrete anterior domain of the cardiac primordia [3].
  • Irx4 is expressed in a subset of cells in the neural retina and the developing hindbrain and also, specifically, in the ventricle of the heart [5].

Analytical, diagnostic and therapeutic context of Irx4

  • All six murine Irx genes are expressed in the developing heart, suggesting that they might possess distinct functions during heart development, and a role for Irx4 in normal heart development has been recently demonstrated by gene-targeting experiments [6].


  1. Cardiomyopathy in Irx4-deficient mice is preceded by abnormal ventricular gene expression. Bruneau, B.G., Bao, Z.Z., Fatkin, D., Xavier-Neto, J., Georgakopoulos, D., Maguire, C.T., Berul, C.I., Kass, D.A., Kuroski-de Bold, M.L., de Bold, A.J., Conner, D.A., Rosenthal, N., Cepko, C.L., Seidman, C.E., Seidman, J.G. Mol. Cell. Biol. (2001) [Pubmed]
  2. The combinatorial activities of Nkx2.5 and dHAND are essential for cardiac ventricle formation. Yamagishi, H., Yamagishi, C., Nakagawa, O., Harvey, R.P., Olson, E.N., Srivastava, D. Dev. Biol. (2001) [Pubmed]
  3. Cardiac expression of the ventricle-specific homeobox gene Irx4 is modulated by Nkx2-5 and dHand. Bruneau, B.G., Bao, Z.Z., Tanaka, M., Schott, J.J., Izumo, S., Cepko, C.L., Seidman, J.G., Seidman, C.E. Dev. Biol. (2000) [Pubmed]
  4. Patterning the embryonic heart: identification of five mouse Iroquois homeobox genes in the developing heart. Christoffels, V.M., Keijser, A.G., Houweling, A.C., Clout, D.E., Moorman, A.F. Dev. Biol. (2000) [Pubmed]
  5. Developmental expression of the Xenopus Iroquois-family homeobox genes, Irx4 and Irx5. Garriock, R.J., Vokes, S.A., Small, E.M., Larson, R., Krieg, P.A. Dev. Genes Evol. (2001) [Pubmed]
  6. The Iroquois homeobox gene Irx2 is not essential for normal development of the heart and midbrain-hindbrain boundary in mice. Lebel, M., Agarwal, P., Cheng, C.W., Kabir, M.G., Chan, T.Y., Thanabalasingham, V., Zhang, X., Cohen, D.R., Husain, M., Cheng, S.H., Bruneau, B.G., Hui, C.C. Mol. Cell. Biol. (2003) [Pubmed]
WikiGenes - Universities