title: Expression patterns of BMPRs in the developing mouse molar.
abstract: During development, Bone Morphogenetic Proteins (BMPs) can induce apoptosis, cell growth or differentiation. These different effects are mediated by dimers of two types of BMP-receptors (BMPRs). To identify the responding cells during tooth development and search for possible tissue-or stage-specificities in the receptors involved, the distribution patterns of BMPR-IA, -IB and -II were investigated in the mouse molar, from bud to bell stage. At the bud stage, BMP-2 was suggested to be involved in the formation of an epithelial signaling center, the primary enamel knot (PEK), while BMP-4 would mediate the condensation of the mesenchyme. Immunostaining showed the presence of BMPR-IA and -II in the epithelium instead of BMPR-IB and -II in the mesenchyme. At the cap stage, BMPR-IB was detected in the epithelium but not BMPR-II, suggesting the existence of another type II receptor to form a functional dimer. At the late cap stage in the epithelium, BMP-4, BMPR-IA and -II were restricted to the internal part of the PEK and the stalk: two apoptotic areas. The three proteins were detected in the mesenchyme, showing a strong staining where cusps were about to form. At the late bell stage, BMP-2 or -4 may induce cell differentiation. BMPR-IB and -II were detected in odontoblasts instead of BMPR-IA and -II in ameloblasts. These results provide the first evidence of multiple type I and type II BMP-receptors, expressed in the dental epithelium and mesenchyme at different stages of development, to signal different cellular activities in a time- and tissue-specific way.
authors.affiliation: INSERM UMR S595, Faculté de Chirurgie Dentaire, Université Louis Pasteur, 67085, Strasbourg, France. amal.nadiri@odonto-ulp.u-strasbg.fr
authors.forename: A
authors.initials: A
authors.lastname: Nadiri
authors.forename: S
authors.initials: S
authors.lastname: Kuchler-Bopp
authors.forename: F
authors.initials: F
authors.lastname: Perrin-Schmitt
authors.forename: H
authors.initials: H
authors.lastname: Lesot
mesh_terms: D000818:Animals; D052004:Bone Morphogenetic Protein Receptors / Q000378:metabolism*; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000378:metabolism; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008813:Mice, Inbred ICR; D008963:Molar / Q000196:embryology* / Q000378:metabolism*
chemical_list: D052004:Bone Morphogenetic Protein Receptors; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II