title: Tooth-type specific expression of dHAND/Hand2: possible involvement in murine lower incisor morphogenesis.
abstract: dHAND/Hand2 is a basic helix-loop-helix transcription factor required for the development of the heart, pharyngeal arches, and vasculature and is expressed during embryogenesis. However, there are no reports on the involvement of the dHAND gene in tooth development. In the present study, the expression of dHAND was examined in developing tooth germs of mice. The dHAND gene was expressed in the mesenchyme of the presumptive incisor region of the lower jaw at an early stage and in the mesenchyme of the lower incisor tooth germ at a later stage. However, the dHAND gene was not expressed in the upper incisor region or the upper and lower molar regions during jaw development. Treatment of tooth germ explants of lower incisors with antisense oligodeoxinucleotide (ODN) against dHAND prevented the differentiation of tooth germ cells, including ameloblasts and odontoblasts, the formation of dentin and enamel, and the proliferation of tooth germ cells and increased the apoptosis of tooth germ cells, suggesting that dHAND is essential for these cells during development. On the other hand, the treatment of tooth germ explants of upper incisor and upper or lower molars did not induce severe effects on their development. Treatment of the explants with basic fibroblast growth factor in association with antisense ODN partially rescued them from the effects of antisense ODN. The present results suggest that the dHAND gene plays important roles in type-specific development of lower incisors, and that basic fibroblast growth factor is involved downstream of the dHAND pathway in tooth germ cells.
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita, Osaka 565-0871, Japan. makoto@dent.osaka-u.ac.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Abe
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tamamura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamagishi
authors.forename: Takashi
authors.initials: T
authors.lastname: Maeda
authors.forename: Joji
authors.initials: J
authors.lastname: Kato
authors.forename: Makoto J
authors.initials: MJ
authors.lastname: Tabata
authors.forename: Deepak
authors.initials: D
authors.lastname: Srivastava
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakisaka
authors.forename: Kojiro
authors.initials: K
authors.lastname: Kurisu
mesh_terms: D000565:Ameloblasts / Q000187:drug effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D003743:Dental Enamel / Q000187:drug effects / Q000378:metabolism; D003804:Dentin / Q000187:drug effects / Q000378:metabolism; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D007180:Incisor / Q000196:embryology* / Q000378:metabolism*; D008334:Mandible / Q000196:embryology; D008648:Mesoderm / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D009024:Morphogenesis; D009804:Odontoblasts / Q000187:drug effects; D009805:Odontogenesis / Q000235:genetics; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D011247:Pregnancy; D012680:Sensitivity and Specificity; D014083:Tooth Germ / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism*; D029961:Zebrafish Proteins
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D016222:Fibroblast Growth Factor 2; D016376:Oligonucleotides, Antisense; D014157:Transcription Factors; D029961:Zebrafish Proteins; C498766:Hand2 protein, mouse; C410915:hand2 protein, zebrafish