title: Antagonistic actions of Msx1 and Osr2 pattern mammalian teeth into a single row.
abstract: Mammals have single-rowed dentitions, whereas many nonmammalian vertebrates have teeth in multiple rows. Neither the molecular mechanism regulating iterative tooth initiation nor that restricting mammalian tooth development in one row is known. We found that mice lacking the transcription factor odd-skipped related-2 (Osr2) develop supernumerary teeth lingual to their molars because of expansion of the odontogenic field. Osr2 was expressed in a lingual-to-buccal gradient and restricted expression of bone morphogenetic protein 4 (Bmp4), an essential odontogenic signal, in the developing tooth mesenchyme. Expansion of odontogenic field in Osr2-deficient mice required Msx1, a feedback activator of Bmp4 expression. These findings suggest that the Bmp4-Msx1 pathway propagates mesenchymal activation for sequential tooth induction and that spatial modulation of this pathway provides a mechanism for patterning vertebrate dentition.
authors.affiliation: Center for Oral Biology and Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors.forename: Zunyi
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Lan
authors.forename: Yang
authors.initials: Y
authors.lastname: Chai
authors.forename: Rulang
authors.initials: R
authors.lastname: Jiang
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000378:metabolism; D003817:Dentition; D004848:Epithelium / Q000196:embryology / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D051957:MSX1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D008648:Mesoderm / Q000196:embryology / Q000378:metabolism; D051379:Mice; D008963:Molar / Q000196:embryology; D009024:Morphogenesis; D009154:Mutation; D009805:Odontogenesis; D014083:Tooth Germ / Q000196:embryology / Q000378:metabolism; D014096:Tooth, Supernumerary / Q000196:embryology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D051957:MSX1 Transcription Factor; C484084:Msx1 protein, mouse; C438618:Osr2 protein, mouse; D014157:Transcription Factors