title: Over- and ectopic expression of Wnt3 causes progressive loss of ameloblasts in postnatal mouse incisor teeth.
abstract: Intercellular signaling is essential for the development of teeth during embryogenesis and in maintenance of the continuously growing incisor teeth in postnatal rodents. WNT intercellular signaling molecules have been implicated in the regulation of tooth development, and the Wnt3 gene shows specific expression in the enamel knot at the cap stage. We demonstrate here that Wnt3 also is expressed in specific epithelial cell layers in postnatal incisor teeth. To begin to delineate the functions of Wnt3 in developing and postnatal teeth, we determined the effects of over- and ectopic expression of Wnt3 in the tooth epithelium of mice carrying a keratin 14-Wnt3 transgene. Expression of the transgene caused a progressive loss of ameloblasts from postnatal lower incisor teeth. Loss of ameloblasts may be due to defective proliferation or differentiation of ameloblast precursors, progressive apoptosis of ameloblasts, or loss of ameloblast stem cells.
authors.affiliation: Department of Dermatology and Cell and Developmental Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. millars@mail.med.upenn.edu
authors.forename: S E
authors.initials: SE
authors.lastname: Millar
authors.forename: E
authors.initials: E
authors.lastname: Koyama
authors.forename: S T
authors.initials: ST
authors.lastname: Reddy
authors.forename: T
authors.initials: T
authors.lastname: Andl
authors.forename: T
authors.initials: T
authors.lastname: Gaddapara
authors.forename: R
authors.initials: R
authors.lastname: Piddington
authors.forename: C W
authors.initials: CW
authors.lastname: Gibson
mesh_terms: D000565:Ameloblasts / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D007180:Incisor / Q000002:abnormalities / Q000254:growth & development*; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D053564:Keratins, Hair-Specific; D051379:Mice; D008822:Mice, Transgenic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000378:metabolism / Q000473:pathology; D014071:Tooth Abnormalities / Q000235:genetics; D051153:Wnt Proteins; D000071818:Wnt-5a Protein
chemical_list: D007381:Intermediate Filament Proteins; D053564:Keratins, Hair-Specific; C115298:Krtap14 protein, mouse; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; C438615:Wnt5a protein, mouse