Rodents have a toothless diastema between the incisor and the first molar, which may contain rudimentary tooth germs. In the lower diastema region of mice at E13, the rudimentary tooth germs, which developed into the bud stage before its removal by apoptosis, was found. The immunoreactivity to tenascin was observed in the condensed mesenchyme around the normal tooth bud and was detected in only the basement membrane in the diastema bud. This result shows that the relationship between mesenchymal condensation and tooth development. The similar patterns of Msx-1 and Msx-2 expression between the tooth bud and the diastema bud show that the diastema bud may have some other genetic mechanism in the developmental arrest of the rudimentary tooth germs rather than the Msx-1 and Msx-2 expression. Strikingly, the induction of the tooth formation was possible using tissue recombination between the oral epithelium of the diastema bud and the dental mesenchyme of the molar tooth bud, which indicates the potential capability of the diastema in the tooth formation. In conclusion, it is suggested that the condensed mesenchyme may be the key to tooth development.
Bibliographical noteFunding Information:
We gratefully acknowledge Dr. Y-P Chen for kind provision of Msx-1 and Msx-2 plasmids. This work supported by grants from Korean Health 21 R&D Project, Ministry of Health and Welfare, Republic of Korea (HMP-01-PJ1-PG1-01CH11-0003), Grant-in-Aid for 2003-Multidisciplinary Research Projects from MEXT, Grant-in-Aid for Scientific Research form Japan Society for Promotion of Science (No. 16591840) and Nihon University Individual Research Grant for (2004) (No. 04-125).
All Science Journal Classification (ASJC) codes
- Cell Biology