Homeobox protein aristaless-like 4 is a protein that in humans is encoded by the ALX4gene. Alx4 belongs to the group-1 aristaless-related genes, a majority of which are linked to the development of the craniofacial and/or appendicular skeleton, along with PRRX1, SHOX, ALX3, and CART1. The Alx4 protein acts as a transcriptional activator and is predominantly expressed in the mesenchyme of the developing embryonic limb buds. Transcripts of this gene are detectable in the lateral plate mesoderm just prior to limb induction. Alx4 expression plays a major role in the determination of spatial orientation of the growing limb bud by aiding in the establishment of anteroposterior polarity of the limb. It does this by working in conjunction with Gli3 and dHand to restrict the expression of Sonic Hedgehog (SHh) to the posterior mesenchyme, which will eventually give rise to the Zone of Polarizing Activity (ZPA). This gene has been proven to be allelic with mutations and deletions giving rise to a host of craniofacial dismorphologies and several forms of polydactyly in mammalian development. A mouse-model knockout of this gene, dubbed Strong’s luxoid, was originally created by Forstheofel in the 1960s and has been extensively studied to understand the partial and complete loss-of-function properties of this gene.
^ abPanman L, Drenth T, Tewelscher P, Zuniga A, Zeller R (2004-07-01). "Genetic interaction of Gli3 and Alx4 during limb development". The International Journal of Developmental Biology. 49 (4): 443–8. doi:10.1387/ijdb.051984lp. PMID15968591.
^ abKuijper S, Feitsma H, Sheth R, Korving J, Reijnen M, Meijlink F (September 2005). "Function and regulation of Alx4 in limb development: complex genetic interactions with Gli3 and Shh". Developmental Biology. 285 (2): 533–44. doi:10.1016/j.ydbio.2005.06.017. PMID16039644.
^ abNiswander L (2002). "Interplay between the molecular signals that control vertebrate limb development". The International Journal of Developmental Biology. 46 (7): 877–81. PMID12455624.
^ abKayserili H, Uz E, Niessen C, Vargel I, Alanay Y, Tuncbilek G, Yigit G, Uyguner O, Candan S, Okur H, Kaygin S, Balci S, Mavili E, Alikasifoglu M, Haase I, Wollnik B, Akarsu NA (November 2009). "ALX4 dysfunction disrupts craniofacial and epidermal development". Human Molecular Genetics. 18 (22): 4357–66. doi:10.1093/hmg/ddp391. PMID19692347.
^Forsthoefel PF (November 1963). "The embryological development of the effects of Strong's luxoid gene in the mouse". Journal of Morphology. 113 (3): 427–51. doi:10.1002/jmor.1051130307. PMID14079603.
Mavrogiannis LA, Antonopoulou I, Baxová A, Kutílek S, Kim CA, Sugayama SM, Salamanca A, Wall SA, Morriss-Kay GM, Wilkie AO (January 2001). "Haploinsufficiency of the human homeobox gene ALX4 causes skull ossification defects". Nature Genetics. 27 (1): 17–8. doi:10.1038/83703. PMID11137991.
Nagase T, Nakayama M, Nakajima D, Kikuno R, Ohara O (April 2001). "Prediction of the coding sequences of unidentified human genes. XX. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro". DNA Research. 8 (2): 85–95. doi:10.1093/dnares/8.2.85. PMID11347906.
Boras K, Hamel PA (January 2002). "Alx4 binding to LEF-1 regulates N-CAM promoter activity". The Journal of Biological Chemistry. 277 (2): 1120–7. doi:10.1074/jbc.M109912200. PMID11696550.
Wakui K, Gregato G, Ballif BC, Glotzbach CD, Bailey KA, Kuo PL, Sue WC, Sheffield LJ, Irons M, Gomez EG, Hecht JT, Potocki L, Shaffer LG (May 2005). "Construction of a natural panel of 11p11.2 deletions and further delineation of the critical region involved in Potocki-Shaffer syndrome". European Journal of Human Genetics. 13 (5): 528–40. doi:10.1038/sj.ejhg.5201366. PMID15852040.