title: Dual odontogenic origins develop at the early stage of rat maxillary incisor development.
abstract: Developmental process of rat maxillary incisor has been studied through histological analysis and investigation of tooth-related gene expression patterns at initial tooth development. The tooth-related genes studied here are fibroblast growth factor-8 (Fgf-8), pituitary homeobox gene-2 (Pitx-2), sonic hedgehog (Shh), muscle segment homeobox-1 (Msx-1), paired box-9 (Pax-9) and bone morphogenetic protein-4 (Bmp-4). The genes are expressed in oral epithelium and/or ectomesenchyme at the stage of epithelial thickening to the early bud stage of tooth development. Both the histological observation and tooth-related gene expression patterns during early stage of maxillary incisor development demonstrate that dual odontogenic origins aligned medio-laterally in the medial nasal process develop, subsequently only single functional maxillary incisor dental placode forms. The cascade of tooth-related gene expression patterns in rat maxillary incisor studied here is quite similar to those of the previous studies in mouse mandibular molar, even though the origins of oral epithelium and ectomesenchyme involved in development of maxillary incisor and mandibular molar are different. Thus, we conclude that maxillary incisor and mandibular molar share a similar signaling control of Fgf-8, Pitx-2, Shh, Msx-1, Pax-9 and Bmp-4 genes at the stage of oral epithelial thickening to the early bud stage of tooth development.
authors.affiliation: Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Henri-Dunant Road, 10330, Bangkok, Thailand.
authors.forename: Rungarun
authors.initials: R
authors.lastname: Kriangkrai
authors.forename: Sachiko
authors.initials: S
authors.lastname: Iseki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Eto
authors.forename: Suconta
authors.initials: S
authors.lastname: Chareonvit
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D051524:Fibroblast Growth Factor 8 / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007180:Incisor / Q000196:embryology* / Q000378:metabolism; D051957:MSX1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D008437:Maxilla / Q000196:embryology*; D009805:Odontogenesis / Q000235:genetics*; D051764:PAX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000097577:Homeobox Protein PITX2
chemical_list: D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D051524:Fibroblast Growth Factor 8; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D051957:MSX1 Transcription Factor; D051764:PAX9 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2; C525810:Bmp4 protein, mouse; C525811:Bmp4 protein, rat; C497998:Msx1 protein, rat