title: The dynamics of supernumerary tooth development are differentially regulated by Sprouty genes.
abstract: In mice, a toothless diastema separates the single incisor from the three molars in each dental quadrant. In the prospective diastema of the embryo, small rudimentary buds are found that are presumed to be rudiments of suppressed teeth. A supernumerary tooth occurs in the diastema of adult mice carrying mutations in either Spry2 or Spry4. In the case of Spry2 mutants, the origin of the supernumerary tooth involves the revitalization of a rudimentary tooth bud (called R2), whereas its origin in the Spry4 mutants is not known. In addition to R2, another rudimentary primordium (called MS) arises more anteriorly in the prospective diastema. We investigated the participation of both rudiments (MS and R2) in supernumerary tooth development in Spry2 and Spry4 mutants by comparing morphogenesis, proliferation, apoptosis, size and Shh expression in the dental epithelium of MS and R2 rudiments. Increased proliferation and decreased apoptosis were found in MS and R2 at embryonic day (ED) 12.5 and 13.5 in Spry2(-/-) embryos. Apoptosis was also decreased in both rudiments in Spry4(-/-) embryos, but the proliferation was lower (similar to WT mice), and supernumerary tooth development was accelerated, exhibiting a cap stage by ED13.5. Compared to Spry2(-/-) mice, a high number of Spry4(-/-) supernumerary tooth primordia degenerated after ED13.5, resulting in a low percentage of supernumerary teeth in adults. We propose that Sprouty genes were implicated during evolution in reduction of the cheek teeth in Muridae, and their deletion can reveal ancestral stages of murine dental evolution.
authors.affiliation: Department of Teratology, Institute of Experimental Medicine AS CR, Prague, Czech Republic. churava@biomed.cas.cz
authors.forename: Svatava
authors.initials: S
authors.lastname: Lagronova-Churava
authors.forename: Frantisek
authors.initials: F
authors.lastname: Spoutil
authors.forename: Simona
authors.initials: S
authors.lastname: Vojtechova
authors.forename: Herve
authors.initials: H
authors.lastname: Lesot
authors.forename: Miroslav
authors.initials: M
authors.lastname: Peterka
authors.forename: Ophir D
authors.initials: OD
authors.lastname: Klein
authors.forename: Renata
authors.initials: R
authors.lastname: Peterkova
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D005075:Biological Evolution; D004848:Epithelium / Q000254:growth & development*; D007180:Incisor / Q000254:growth & development / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008963:Molar / Q000254:growth & development / Q000378:metabolism; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009805:Odontogenesis; D017346:Protein Serine-Threonine Kinases; D015398:Signal Transduction; D014070:Tooth / Q000254:growth & development*; D014096:Tooth, Supernumerary / Q000473:pathology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C499037:Spry4 protein, mouse; D017346:Protein Serine-Threonine Kinases; C118389:Spry2 protein, mouse