Amelogenin, X isoform is a protein that in humans is encoded by the ''AMELX''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
AMELX is located on the
X chromosome
The X chromosome is one of the two sex-determining chromosomes (allosomes) in many organisms, including mammals (the other is the Y chromosome), and is found in both males and females. It is a part of the XY sex-determination system and XO sex ...
and encodes a set of isoforms of
amelogenin
Amelogenins are a group of protein isoforms produced by alternative splicing or proteolysis from the ''AMELX'' gene, on the X chromosome, and also the ''AMELY'' gene in males, on the Y chromosome. They are involved in amelogenesis, the developme ...
by
alternative splicing
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be i ...
.
Amelogenin is an
extracellular matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide s ...
protein involved in the process of
amelogenesis
Amelogenesis is the formation of enamel on teeth and begins when the crown is forming during the advanced bell stage of tooth development after dentinogenesis forms a first layer of dentin. Dentin must be present for enamel to be formed. Amelob ...
, the formation of
enamel on teeth.
Function
AMELX is involved in
biomineralization
Biomineralization, also written biomineralisation, is the process by which living organisms produce minerals, often to harden or stiffen existing tissues. Such tissues are called mineralized tissues. It is an extremely widespread phenomenon; ...
during
tooth enamel
Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, ...
development.
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
Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. ...
crystals.
Clinical significance
Mutations in ''AMELX'' result in
amelogenesis imperfecta
Amelogenesis imperfecta (AI) is a congenital disorder which presents with a rare abnormal formation of the enamel or external layer of the crown of teeth, unrelated to any systemic or generalized conditions. Enamel is composed mostly of mineral, ...
.
It has been shown that mice with a
knocked-out ''AMELX'' gene will present disorganized and hypoplastic enamel.
See also
*
AMELY
Amely was an American rock band from Orlando, Florida, United States, formed in 2008. The band comprised four members; Petie Pizarro (Vocals/Guitar), Brandon Walden (Guitar), Patrick Ridgen (Bass) and Nate Parsell (Drums). The sound of the band ...
References
External links
*
Further reading
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
Genes on human chromosome X
Genetics
{{Gene-X-stub