title: Amelotin gene expression is temporarily being upregulated at the initiation of apoptosis induced by TGFβ1 in mouse gingival epithelial cells.
abstract: Amelotin (AMTN) is expressed and secreted by ameloblasts in the maturation stage of amelogenesis and persist with low levels in the junctional epithelium (JE) of erupted teeth. The purpose of this study is to investigate the transcriptional regulation of the AMTN gene by transforming growth factor beta1 (TGFβ1) in gingival epithelial (GE1) cells in the apoptosis phase. Apoptosis was evaluated by the fragmentation of chromosomal DNA and TUNEL staining. A real-time PCR was carried out to examine the AMTN mRNA levels induced by TGFβ1 and Smad3 overexpression. Transient transfection analyses were completed using the various lengths of mouse AMTN gene promoter constructs with or without TGFβ1. Chromatin immunoprecipitation (ChIP) assays were performed to investigate the Smad3 bindings to the AMTN gene promoter by TGFβ1. TGFβ1-induced apoptosis in GE1 cells were detected at 24 and 48 h by DNA fragmentation and TUNEL staining. AMTN mRNA levels increased at 6 h and reached maximum at 24 h in GE1 cells. Luciferase activities of the mouse AMTN gene promoter constructs were induced by TGFβ1. The results of the ChIP assays showed that there was an increase in Smad3 binding to Smad-binding element (SBE)#1 and SBE#2 after stimulation by TGFβ1. Immunohistochemical localization of AMTN was detected in the JE, and the AMTN protein levels in Smad3-deficient mice were decreased compared with wild-type mice. AMTN mRNA levels were induced at the initiation of apoptosis by TGFβ1, which mediated through the Smad3 bindings to SBEs in the mouse AMTN gene promoter.
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan. nakayama.youhei@nihon-u.ac.jp.|Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, Japan. nakayama.youhei@nihon-u.ac.jp.
authors: Yohei
authors: Y
authors: Nakayama
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors: Sari
authors: S
authors: Matsui
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors: Keisuke
authors: K
authors: Noda
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors: Mizuho
authors: M
authors: Yamazaki
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors: Yasunobu
authors: Y
authors: Iwai
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors: Hiroyoshi
authors: H
authors: Matsumura
authors: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors: Takashi
authors: T
authors: Izawa
authors: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors: Eiji
authors: E
authors: Tanaka
authors: Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.
authors: Bernhard
authors: B
authors: Ganss
authors: Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, Japan. ogata.yorimasa@nihon-u.ac.jp.|Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, Japan. ogata.yorimasa@nihon-u.ac.jp.
authors: Yorimasa
authors: 0000-0002-2767-844X
authors: Y
authors: Ogata
mesh_terms: D000818:Animals; D017209:Apoptosis; D003746:Dental Enamel Proteins / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005881:Gingiva / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D011401:Promoter Regions, Genetic; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C507066:Amtn protein, mouse; D003746:Dental Enamel Proteins; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1
keywords: Amelotin; Apoptosis; Junctional epithelium; Smad3; TGFβ1