Expression and role of Lhx8 in murine tooth development.
We examined the expression and possible functions of Lhx8, a member of the LIM-homeobox gene family, during tooth morphogenesis of the mouse. Lhx8 was expressed in the dental mesenchyme between the bud and early bell stage of the molar tooth germ. Tooth germ explants from embryonic day 12.5 mice treated for 5 to 7 days with antisense-oligodeoxynucleotides (AS-ODN) against Lhx8 showed a marked decrease in the number of mesenchymal cells. The explants treated with AS-ODN for 11 to 14 days were filled with a large number of undifferentiated epithelial cells and a limited number of undifferentiated mesenchymal cells, but did not contain a tooth germ. Treatment of explants with AS-ODN for 7 days suppressed the proliferation of dental mesenchymal cells and induced apoptosis; the latter was confirmed by histochemical and ultrastructural examinations. Moreover, the expression of Lhx6, Msx1, Msx2, Bmp4 and Gsc, which are also known to be involved in tooth morphogenesis, were suppressed after the application of AS-ODN against Lhx8 for 7 days. The present results suggest that Lhx8 plays an important role in the survival of mesenchymal cells of the tooth germ during development.
Shibaguchi
Tatsuya
T
Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
Kato
Joji
J
Abe
Makoto
M
Tamamura
Yoshihiro
Y
Tabata
Makoto J
MJ
Liu
Ji-Guang
JG
Iwamoto
Masahiro
M
Wakisaka
Satoshi
S
Wanaka
Akio
A
Kurisu
Kojiro
K
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002455:Cell Division; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism*; D060850:LIM-Homeodomain Proteins; D008648:Mesoderm / Q000502:physiology; D051379:Mice; D008813:Mice, Inbred ICR; D008854:Microscopy, Electron; D008963:Molar / Q000196:embryology / Q000502:physiology; D016376:Oligonucleotides, Antisense; D009924:Organ Culture Techniques; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014083:Tooth Germ / Q000196:embryology* / Q000502:physiology* / Q000648:ultrastructure; D014157:Transcription Factors
D018398:Homeodomain Proteins; C112960:LIM homeobox protein 8; D060850:LIM-Homeodomain Proteins; D016376:Oligonucleotides, Antisense; D014157:Transcription Factors