title: Membranes, minerals, and proteins of developing vertebrate enamel.
abstract: Developing tooth enamel is formed as organized mineral in a specialized protein matrix. In order to analyze patterns of enamel mineralization and enamel protein expression in species representative of the main extant vertebrate lineages, we investigated developing teeth in a chondrichthyan, the horn shark, a teleost, the guppy, a urodele amphibian, the Mexican axolotl, an anuran amphibian, the leopard frog, two lepidosauria, a gecko and an iguana, and two mammals, a marsupial, the South American short-tailed gray opossum, and the house mouse. Electron microscopic analysis documented the presence of a distinct basal lamina in all species investigated. Subsequent stages of enamel biomineralization featured highly organized long and parallel enamel crystals in mammals, lepidosaurians, the frog, and the shark, while amorphous mineral deposits and/or randomly oriented crystals were observed in the guppy and the axolotl. In situ hybridization using a full-length mouse probe for amelogenin mRNA resulted in amelogenin specific signals in mouse, opossum, gecko, frog, axolotl, and shark. Using immunohistochemistry, amelogenin and tuftelin enamel proteins were detected in the enamel organ of many species investigated, but tuftelin epitopes were also found in other tissues. The anti-M179 antibody, however, did not react with the guppy and axolotl enameloid matrix. We conclude that basic features of vertebrate enamel/enameloid formation such as the presence of enamel proteins or the mineral deposition along the dentin-enamel junction were highly conserved in vertebrates. There were also differences in terms of enamel protein distribution and mineral organization between the vertebrates lineages. Our findings indicated a correlation between the presence of amelogenins and the presence of long and parallel hydroxyapatite crystals in tetrapods and shark.
authors.affiliation: Allan G. Brodie Laboratory for Craniofacial Genetics, University of Illinois at Chicago, Illinois, USA.
authors.forename: Thomas G H
authors.initials: TG
authors.lastname: Diekwisch
authors.forename: Brett J
authors.initials: BJ
authors.lastname: Berman
authors.forename: Xochitl
authors.initials: X
authors.lastname: Anderton
authors.forename: Brian
authors.initials: B
authors.lastname: Gurinsky
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Ortega
authors.forename: Paul G
authors.initials: PG
authors.lastname: Satchell
authors.forename: Mia
authors.initials: M
authors.lastname: Williams
authors.forename: Chithra
authors.initials: C
authors.lastname: Arumugham
authors.forename: Xianghong
authors.initials: X
authors.lastname: Luan
authors.forename: James E
authors.initials: JE
authors.lastname: McIntosh
authors.forename: Akira
authors.initials: A
authors.lastname: Yamane
authors.forename: David S
authors.initials: DS
authors.lastname: Carlson
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Sire
authors.forename: Charles F
authors.initials: CF
authors.lastname: Shuler
mesh_terms: D053523:Amelogenin; D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D005075:Biological Evolution; D003743:Dental Enamel / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure*; D003746:Dental Enamel Proteins / Q000032:analysis* / Q000235:genetics; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009805:Odontogenesis; D012333:RNA, Messenger / Q000032:analysis; D014074:Tooth Calcification; D014714:Vertebrates
chemical_list: D053523:Amelogenin; C507200:Amelx protein, mouse; D003746:Dental Enamel Proteins; D012333:RNA, Messenger; C038456:tuftelin