Tooth-type specific expression of dHAND/Hand2: possible involvement in murine lower incisor morphogenesis

Cell Tissue Res. 2002 Nov;310(2):201-12. doi: 10.1007/s00441-002-0611-2. Epub 2002 Sep 14.


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.

MeSH terms

  • Ameloblasts / drug effects
  • Animals
  • Apoptosis / drug effects
  • Basic Helix-Loop-Helix Transcription Factors
  • Cell Differentiation / drug effects
  • Cell Division / drug effects
  • Cells, Cultured
  • DNA-Binding Proteins / drug effects
  • DNA-Binding Proteins / metabolism*
  • Dental Enamel / drug effects
  • Dental Enamel / metabolism
  • Dentin / drug effects
  • Dentin / metabolism
  • Female
  • Fibroblast Growth Factor 2 / pharmacology
  • Gene Expression Regulation, Developmental*
  • Incisor / embryology*
  • Incisor / metabolism*
  • Mandible / embryology
  • Mesoderm / metabolism
  • Mice
  • Mice, Inbred ICR
  • Morphogenesis
  • Odontoblasts / drug effects
  • Odontogenesis / genetics
  • Oligonucleotides, Antisense / pharmacology
  • Pregnancy
  • Sensitivity and Specificity
  • Tooth Germ / drug effects
  • Tooth Germ / embryology
  • Tooth Germ / metabolism
  • Transcription Factors / drug effects
  • Transcription Factors / metabolism*
  • Zebrafish Proteins


  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Hand2 protein, mouse
  • Oligonucleotides, Antisense
  • Transcription Factors
  • Zebrafish Proteins
  • hand2 protein, zebrafish
  • Fibroblast Growth Factor 2