PMID- 19090534
OWN - NLM
STAT- MEDLINE
DCOM- 20090729
LR  - 20181201
IS  - 1552-5015 (Electronic)
IS  - 1552-5007 (Linking)
VI  - 312B
IP  - 5
DP  - 2009 Jul 15
TI  - Reduction of Egf signaling decides transition from crown to root in the 
      development of mouse molars.
PG  - 486-94
LID - 10.1002/jez.b.21268 [doi]
AB  - Mouse, rat, and human molars begin to form their roots after the completion of 
      crown morphogenesis. Though several signaling pathways and transcription factors 
      have been implicated in the regulation of molar crown development, relatively 
      little is known about the regulatory mechanisms involved in the transition from 
      crown to root development. Tooth root formation is initiated by the development 
      of Hertwig's epithelial root sheath (HERS) from the cervical loop in the enamel 
      organ. In this study we examined the change in epidermal growth factor (Egf) 
      signaling during this transition process. Immunohistochemical studies showed that 
      the expression of Egf receptors in the enamel organ disappear gradually in the 
      process and are not observed in HERS. Here, to examine the effect of Egf on the 
      transition, we used the organ culture method to examine the root development. In 
      the presence of Egf, stellate reticulum (SR) cells between the inner and outer 
      epithelial layers in the enamel organ actively proliferated and maintained the 
      enamel organ, and the formation of HERS was not observed. On the other hand, in 
      either the absence of Egf or the presence of the inhibitor of Egf receptors, the 
      SR cells disappeared and HERS formation started. Subsequently, root formation 
      proceeded in the culture period. Therefore, disappearance of SR area may be a key 
      event that controls the timing of onset of HERS formation, and Egf may be one of 
      regulatory factors involved in the change from cervical loop epithelium to HERS 
      during root development.
CI  - (c) 2008 Wiley-Liss, Inc.
FAU - Fujiwara, Naoki
AU  - Fujiwara N
AD  - Department of Oral Anatomy II, School of Dentistry, Iwate Medical University, 
      Morioka, Iwate, Japan.
FAU - Akimoto, Tadashi
AU  - Akimoto T
FAU - Otsu, Keishi
AU  - Otsu K
FAU - Kagiya, Tadayoshi
AU  - Kagiya T
FAU - Ishizeki, Kiyoto
AU  - Ishizeki K
FAU - Harada, Hidemitsu
AU  - Harada H
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Exp Zool B Mol Dev Evol
JT  - Journal of experimental zoology. Part B, Molecular and developmental evolution
JID - 101168228
RN  - 62229-50-9 (Epidermal Growth Factor)
RN  - EC 2.7.10.1 (ErbB Receptors)
SB  - IM
MH  - Aging/physiology
MH  - Animals
MH  - Animals, Newborn
MH  - Cell Differentiation
MH  - Cell Division
MH  - Epidermal Growth Factor/*genetics/physiology
MH  - ErbB Receptors/genetics
MH  - Gene Expression Regulation
MH  - Immunohistochemistry
MH  - Mice
MH  - Molar/cytology/*growth & development
MH  - *Signal Transduction
MH  - Tooth Crown/cytology/*physiology
MH  - Tooth Root/cytology/*physiology
EDAT- 2008/12/19 09:00
MHDA- 2009/07/30 09:00
CRDT- 2008/12/19 09:00
PHST- 2008/12/19 09:00 [entrez]
PHST- 2008/12/19 09:00 [pubmed]
PHST- 2009/07/30 09:00 [medline]
AID - 10.1002/jez.b.21268 [doi]
PST - ppublish
SO  - J Exp Zool B Mol Dev Evol. 2009 Jul 15;312B(5):486-94. doi: 10.1002/jez.b.21268.