title: p27(kip1) deficiency accelerates dentin and alveolar bone formation.
abstract: To assess the role of p27(kip1) in regulating dental formation and alveolar bone development, we compared the teeth and mandible phenotypes of homozygous p27(kip1) -deficient (p27(-/-) ) mice with their wild-type littermates at 2 weeks of age. At 2 weeks of age, dental mineral density, dental volume and dentin sialoprotein-immunopositive areas were increased significantly, whereas the predentin area : total dentin area and biglycan-immunopositive area : dentin area ratios were decreased significantly in p27(-/-) mice compared with their wild-type (WT) littermates. Mandible mineral density, cortical thickness, alveolar bone volume, type I collagen and osterix-immunopositive areas, osteoblast number and activity and mRNA expression of Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteocalcin and bone morphogenetic protein (bmp2) were all significantly increased in the mandibles, as was the number and surface of tartrate-resistant acid phosphatase-positive osteoclasts in the alveolar bone of p27(-/-) mice compared with their WT littermates. Furthermore, the percentage of proliferating cell nuclear antigen-positive cells in Hertwig's epithelial root sheath and protein expression of cyclin E and cyclin-dependent kinase 2 were increased significantly in p27(-/-) mice relative to their WT littermates. The results from this study indicate that p27 plays a negative regulatory role in dentin formation and alveolar bone development.
authors.affiliation: Institute of Stomatology, Nanjing Medical University, Nanjing, China; State Key Laboratory of Reproductive Medicine, The Research Center for Bone and Stem Cells, Department of Anatomy Histology and Embryology, Nanjing Medical University, Nanjing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yin
authors.forename: Qun
authors.initials: Q
authors.lastname: Wang
authors.forename: Wen
authors.initials: W
authors.lastname: Sun
authors.forename: Yuli
authors.initials: Y
authors.lastname: Wang
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.forename: Dengshun
authors.initials: D
authors.lastname: Miao
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015519:Bone Density / Q000502:physiology; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000172:deficiency*; D003804:Dentin / Q000378:metabolism / Q000502:physiology*; D008334:Mandible / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000378:metabolism / Q000502:physiology; D015675:Osteocalcin / Q000378:metabolism; D010010:Osteoclasts / Q000378:metabolism / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology*
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; C493961:Cdkn1b protein, mouse; D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D019927:Cyclin E; C493716:Runx2 protein, mouse; D015675:Osteocalcin; D050760:Cyclin-Dependent Kinase Inhibitor p27; D051357:Cyclin-Dependent Kinase 2; D000469:Alkaline Phosphatase
keywords: development; mandible; p27; tooth