AMELX explained

Amelogenin, X isoform is a protein that in humans is encoded by the AMELX gene.^[1] AMELX is located on the X chromosome and encodes a set of isoforms of amelogenin by alternative splicing.^{[2] [3]} Amelogenin is an extracellular matrix protein involved in the process of amelogenesis, the formation of enamel on teeth.

Function

AMELX is involved in biomineralization during tooth enamel development.^[4] The AMELX gene encodes for the structural modeling protein, amelogenin, which works with other amelogenesis-related proteins to direct the mineralisation of enamel. This process involves the organization of enamel rods, the basic unit of tooth enamel, as well as the inclusion and growth of hydroxyapatite crystals.

Clinical significance

Mutations in AMELX result in amelogenesis imperfecta.^[5] It has been shown that mice with a knocked-out AMELX gene will present disorganized and hypoplastic enamel.^[6]

See also

• AMELY

Further reading

• Zhu L, Tanimoto K, Le T, DenBesten PK, Li W . Functional roles of prolines at amelogenin C terminal during tooth enamel formation . Cells Tissues Organs . 189 . 1–4 . 203–6 . 2009 . 18701806 . 2824197 . 10.1159/000151376 .
• Lee SK, Seymen F, Kang HY, Lee KE, Gencay K, Tuna B, Kim JW . MMP20 hemopexin domain mutation in amelogenesis imperfecta . Journal of Dental Research . 89 . 1 . 46–50 . Jan 2010 . 19966041 . 3318044 . 10.1177/0022034509352844 .
• Sufliarska S, Minarik G, Horakova J, Bodova I, Bojtarova E, Czako B, Mistrik M, Drgona L, Demitrovicova M, Lakota J, Krivosikova M, Kovacs L . Establishing the method of chimerism monitoring after allogeneic stem cell transplantation using multiplex polymerase chain reaction amplification of short tandem repeat markers and Amelogenin . Neoplasma . 54 . 5 . 424–30 . 2007 . 17688372 .
• Tarasevich BJ, Lea S, Bernt W, Engelhard MH, Shaw WJ . Changes in the quaternary structure of amelogenin when adsorbed onto surfaces . Biopolymers . 91 . 2 . 103–7 . Feb 2009 . 19025992 . 2655232 . 10.1002/bip.21095 .
• Chen AP, Chen Y, Wang HP, Chen WH, Chen H, Chen LX, Sun HY . [Types and frequencies of variants in Amelogenin gene in Chinese population] . Zhonghua Yi Xue Yi Chuan Xue Za Zhi = Zhonghua Yixue Yichuanxue Zazhi = Chinese Journal of Medical Genetics . 24 . 6 . 615–9 . Dec 2007 . 18067069 .
• Barbe L, Lundberg E, Oksvold P, Stenius A, Lewin E, Björling E, Asplund A, Pontén F, Brismar H, Uhlén M, Andersson-Svahn H . Toward a confocal subcellular atlas of the human proteome . Molecular & Cellular Proteomics . 7 . 3 . 499–508 . Mar 2008 . 18029348 . 10.1074/mcp.M700325-MCP200 . free .
• Deeley K, Letra A, Rose EK, Brandon CA, Resick JM, Marazita ML, Vieira AR . Possible association of amelogenin to high caries experience in a Guatemalan-Mayan population . Caries Research . 42 . 1 . 8–13 . 2008 . 18042988 . 2814012 . 10.1159/000111744 .
• Kim JW, Simmer JP, Hu YY, Lin BP, Boyd C, Wright JT, Yamada CJ, Rayes SK, Feigal RJ, Hu JC . Amelogenin p.M1T and p.W4S mutations underlying hypoplastic X-linked amelogenesis imperfecta . Journal of Dental Research . 83 . 5 . 378–83 . May 2004 . 15111628 . 10.1177/154405910408300505 . 30444755 .
• Wright JT, Hart TC, Hart PS, Simmons D, Suggs C, Daley B, Simmer J, Hu J, Bartlett JD, Li Y, Yuan ZA, Seow WK, Gibson CW . Human and mouse enamel phenotypes resulting from mutation or altered expression of AMEL, ENAM, MMP20 and KLK4 . Cells Tissues Organs . 189 . 1–4 . 224–9 . 2009 . 18714142 . 2754863 . 10.1159/000151378 .
• Richard B, Delgado S, Gorry P, Sire JY . A study of polymorphism in human AMELX . Archives of Oral Biology . 52 . 11 . 1026–31 . Nov 2007 . 17645864 . 10.1016/j.archoralbio.2007.06.001 .
• Patir A, Seymen F, Yildirim M, Deeley K, Cooper ME, Marazita ML, Vieira AR . Enamel formation genes are associated with high caries experience in Turkish children . Caries Research . 42 . 5 . 394–400 . 2008 . 18781068 . 2820320 . 10.1159/000154785 .
• Veis A . Amelogenin gene splice products: potential signaling molecules . Cellular and Molecular Life Sciences . 60 . 1 . 38–55 . Jan 2003 . 12613657 . 10.1007/s000180300003 . 34174000 . 11138844 .
• Tanimoto K, Le T, Zhu L, Witkowska HE, Robinson S, Hall S, Hwang P, Denbesten P, Li W . Reduced amelogenin-MMP20 interactions in amelogenesis imperfecta . Journal of Dental Research . 87 . 5 . 451–5 . May 2008 . 18434575 . 10.1177/154405910808700516 . 3677966 .
• Hart PS, Aldred MJ, Crawford PJ, Wright NJ, Hart TC, Wright JT . Amelogenesis imperfecta phenotype-genotype correlations with two amelogenin gene mutations . Archives of Oral Biology . 47 . 4 . 261–5 . Apr 2002 . 11922869 . 10.1016/S0003-9969(02)00003-1 .
• Tomas C, Stangegaard M, Børsting C, Hansen AJ, Morling N . Typing of 48 autosomal SNPs and amelogenin with GenPlex SNP genotyping system in forensic genetics . Forensic Science International: Genetics . 3 . 1 . 1–6 . Dec 2008 . 19083859 . 10.1016/j.fsigen.2008.06.007 .
• Hart PS, Hart TC, Simmer JP, Wright JT . A nomenclature for X-linked amelogenesis imperfecta . Archives of Oral Biology . 47 . 4 . 255–60 . Apr 2002 . 11922868 . 10.1016/S0003-9969(02)00005-5 .
• Deutsch D, Haze-Filderman A, Blumenfeld A, Dafni L, Leiser Y, Shay B, Gruenbaum-Cohen Y, Rosenfeld E, Fermon E, Zimmermann B, Haegewald S, Bernimoulin JP, Taylor AL . Amelogenin, a major structural protein in mineralizing enamel, is also expressed in soft tissues: brain and cells of the hematopoietic system . European Journal of Oral Sciences . 114 . 183–9; discussion 201–2, 381 . May 2006 . Suppl 1 . 16674683 . 10.1111/j.1600-0722.2006.00301.x .

Notes and References

1. Web site: Entrez Gene: amelogenin (amelogenesis imperfecta 1.
2. Web site: AceView: Gene:AMELX, a comprehensive annotation of human, mouse and worm genes with mRNAs or ESTsAceView . National Center for Biotechnology Information, United States National Institutes of Health .
3. Salido EC, Yen PH, Koprivnikar K, Yu LC, Shapiro LJ . The human enamel protein gene amelogenin is expressed from both the X and the Y chromosomes . American Journal of Human Genetics . 50 . 2 . 303–16 . Feb 1992 . 1734713 . 1682460 .
4. Gibson CW, Yuan ZA, Hall B, Longenecker G, Chen E, Thyagarajan T, Sreenath T, Wright JT, Decker S, Piddington R, Harrison G, Kulkarni AB . Amelogenin-deficient mice display an amelogenesis imperfecta phenotype . The Journal of Biological Chemistry . 276 . 34 . 31871–5 . Aug 2001 . 11406633 . 10.1074/jbc.M104624200 . free .
5. Wright JT . The molecular etiologies and associated phenotypes of amelogenesis imperfecta . American Journal of Medical Genetics Part A . 140 . 23 . 2547–55 . Dec 2006 . 16838342 . 1847600 . 10.1002/ajmg.a.31358 .
6. Li Y, Suggs C, Wright JT, Yuan ZA, Aragon M, Fong H, Simmons D, Daly B, Golub EE, Harrison G, Kulkarni AB, Gibson CW . Partial rescue of the amelogenin null dental enamel phenotype . The Journal of Biological Chemistry . 283 . 22 . 15056–15062 . May 2008 . 18390542 . 10.1074/jbc.M707992200 . 2397487. free .