title: Nfic regulates tooth root patterning and growth.
abstract: Molecular interactions between epithelium and mesenchyme are important for root formation. Nuclear factor I-C (Nfic) has been identified as a key regulator of root formation. However, the mechanisms of root formation and their interactions between Hertwig's epithelial root sheath (HERS) and mesenchyme remain unclear. In this study, we investigated the role of Nfic in root patterning and growth during molar root development. The molars of Nfic knockout mice exhibited an enlarged pulp chamber and apical displacement of the pulpal floor, characteristic features of taurodontism, due to delayed furcation formation. In developing molar roots of mutant mice at P14, BrdU positive cells decreased in the apical mesenchyme of the elongation region whereas those cells increased in the dental papilla of the furcation region. Whereas cytokeratin 14 and laminin were localized in HERS cells of mutant molars, Smoothened (Smo) and Gli1 were downregulated in preodontoblasts. In contrast, cytokeratin 14 and Smo were localized in the cells of the furcation region of mutant molars. These results indicate that Nfic regulates cell proliferation in the dental mesenchyme and affects the fate of HERS cells in a site-specific manner. From the results, it is suggested that Nfic is required for root patterning and growth during root morphogenesis.
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Tak-Heun
authors.initials: TH
authors.lastname: Kim
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Cheol-Hyeon
authors.initials: CH
authors.lastname: Bae
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Siqin
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Oral Histology-Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Joo-Cheol
authors.initials: JC
authors.lastname: Park
authors.affiliation: Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences, School of Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Eui-Sic
authors.initials: ES
authors.lastname: Cho
keywords: Cell proliferation; HERS; Nfic; Root patterning; Taurodontism