Ameloblastin

AMBN
Identifiers
Aliases	AMBN, AI1F, Sheathlin, ameloblastin
External IDs	OMIM: 601259 MGI: 104655 HomoloGene: 7625 GeneCards: AMBN
Gene location (Human) Chr. Chromosome 4 (human) Band 4q13.3 Start 70,592,256 bp End 70,607,288 bp
Gene location (Mouse) Chr. Chromosome 5 (mouse) Band 5 E1|5 43.63 cM Start 88,603,850 bp End 88,616,390 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in putamen caudate nucleus nucleus accumbens islet of Langerhans prefrontal cortex mesencephalon hypothalamus substantia nigra spleen lymphatic system Top expressed in molar membranous bone maxilla human mandible sexually immature organism fossa incisor dermis condyle olfactory epithelium More reference expression data BioGPS n/a
Gene ontology Molecular function structural constituent of tooth enamel growth factor activity protein binding Cellular component extracellular region endoplasmic reticulum lumen Biological process odontogenesis of dentin-containing tooth biomineral tissue development cell adhesion cell population proliferation post-translational protein modification regulation of signaling receptor activity regulation of cell population proliferation signal transduction Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 258 11698 Ensembl ENSG00000178522 ENSMUSG00000029288 UniProt Q9NP70 O55189 RefSeq (mRNA) NM_016519 NM_009664 NM_001303431 RefSeq (protein) NP_057603 NP_001290360 NP_033794 Location (UCSC) Chr 4: 70.59 – 70.61 Mb Chr 5: 88.6 – 88.62 Mb PubMed search
Wikidata
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Ameloblastin (abbreviated AMBN and also known as sheathlin or amelin) is an enamel matrix protein that in humans is encoded by the AMBN gene.

Function

Ameloblastin is a specific protein found in tooth enamel. Although less than 5% of enamel consists of protein, ameloblastins constitute 5–10% of all enamel protein, making it the second most abundant enamel matrix protein. This protein is formed by ameloblasts during the early secretory to late maturation stages of amelogenesis. Although not completely understood, the function of ameloblastins is believed to be in controlling the elongation of enamel crystals and generally directing enamel mineralization during tooth development. Ameloblastin helps in the growth of a crystalline enameloid layer consisting of randomly oriented short enamel crystals. Ameloblastin cleavage products are found in the sheath space between rod and interrod enamel, while intact ameloblastin accumulates on the enamel rods. This difference in localization is thought to maintain the boundary between rod and interrod enamel.

Ameloblastin is generally implicated in enamel development, but may also have a role in root development. Other possible actions include bone remodeling and repair, although this function has yet to be definitively proven.

Other significant proteins in enamel are amelogenins, enamelins, and tuftelins.

Clinical significance

Mutations in AMBN cause amelogenesis imperfecta, a disease characterized by abnormal enamel formation resulting in discolored, pitted, or spotted enamel. These mutations are rare, and follow an autosomal recessive pattern of inheritance.

References

• This article incorporates text from the United States National Library of Medicine, which is in the public domain.

Further reading

• Bartlett JD, Simmer JP (1999). "Proteinases in developing dental enamel". Critical Reviews in Oral Biology and Medicine. 10 (4): 425–441. doi:10.1177/10454411990100040101. PMID 10634581.
• MacDougall M, DuPont BR, Simmons D, Reus B, Krebsbach P, Kärrman C, et al. (April 1997). "Ameloblastin gene (AMBN) maps within the critical region for autosomal dominant amelogenesis imperfecta at chromosome 4q21". Genomics. 41 (1): 115–118. doi:10.1006/geno.1997.4643. PMID 9126491.
• Kuroda S, Wazen R, Sellin K, Tanaka E, Moffatt P, Nanci A (July 2011). "Ameloblastin is not implicated in bone remodelling and repair". European Cells & Materials. 22: 56–66, discussion 66–7. doi:10.22203/eCM.v022a05. PMID 21761392.
• Perdigão PF, Carvalho VM, DE Marco L, Gomez RS (August 2009). "Mutation of ameloblastin gene in calcifying epithelial odontogenic tumor". Anticancer Research. 29 (8): 3065–3067. PMID 19661317.
• Tamburstuen MV, Reseland JE, Spahr A, Brookes SJ, Kvalheim G, Slaby I, et al. (February 2011). "Ameloblastin expression and putative autoregulation in mesenchymal cells suggest a role in early bone formation and repair". Bone. 48 (2): 406–413. doi:10.1016/j.bone.2010.09.007. PMC 4469498. PMID 20854943.
• Toyosawa S, Fujiwara T, Ooshima T, Shintani S, Sato A, Ogawa Y, et al. (October 2000). "Cloning and characterization of the human ameloblastin gene". Gene. 256 (1–2): 1–11. doi:10.1016/s0378-1119(00)00379-6. PMID 11054529.
• Patir A, Seymen F, Yildirim M, Deeley K, Cooper ME, Marazita ML, Vieira AR (2008). "Enamel formation genes are associated with high caries experience in Turkish children". Caries Research. 42 (5): 394–400. doi:10.1159/000154785. PMC 2820320. PMID 18781068.
• Lee SK, Krebsbach PH, Matsuki Y, Nanci A, Yamada KM, Yamada Y (December 1996). "Ameloblastin expression in rat incisors and human tooth germs". The International Journal of Developmental Biology. 40 (6): 1141–1150. PMID 9032019.
• Niu CH, Li TJ (November 2006). "[Mutation and polymorphism of the ameloblastin gene in ameloblastomas]". Zhonghua Kou Qiang Yi Xue Za Zhi = Zhonghua Kouqiang Yixue Zazhi = Chinese Journal of Stomatology (in Chinese). 41 (11): 678–681. PMID 17331365.

External links

• Human AMBN genome location and AMBN gene details page in the UCSC Genome Browser.