title: Dental enamel structure is altered by expression of dominant negative RhoA in ameloblasts.
abstract: Using in vitrotooth germ cultures and analysis by confocal microscopy, ameloblasts treated with sodium fluoride were found to have elevated amounts of filamentous actin. Because this response is reduced by inhibitors of the Rho/ROCK signaling pathway, we generated mice that express dominant negative RhoA (RhoA(DN)) in ameloblasts for in vivo analysis. Expression of the EGFP-RhoA(DN) fusion protein was evaluated by RT-PCR and immunohistochemistry, and teeth were analyzed by scanning electron microscopy. The 3 strains expressed at either low (TgEGFP-RhoA(DN)-8), intermediate (TgEGFP-RhoA(DN)-2), or high (TgEGFP-RhoA(DN)-13) levels, and the molar teeth from the 3 strains had enamel hypoplasia and surface defects. We conclude that RhoA(DN) expressed in ameloblasts interferes with normal enamel development through the pathway that is induced by sodium fluoride.
authors.affiliation: Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pa., USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Megan K
authors.initials: MK
authors.lastname: Pugach
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Kuehl
authors.forename: Li
authors.initials: L
authors.lastname: Peng
authors.forename: Jessica
authors.initials: J
authors.lastname: Bouchard
authors.forename: Soon Y
authors.initials: SY
authors.lastname: Hwang
authors.forename: Carolyn W
authors.initials: CW
authors.lastname: Gibson
mesh_terms: D000565:Ameloblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D003743:Dental Enamel / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology* / Q000648:ultrastructure; D005799:Genes, Dominant / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D008963:Molar / Q000187:drug effects / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D014083:Tooth Germ / Q000187:drug effects / Q000473:pathology; D019076:Transgenes / Q000235:genetics; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D020742:rhoA GTP-Binding Protein