[Expression of homeobox gene Msx-1, Msx-2 and Dlx-2 during murine mandibular first molar development].
OBJECTIVE
To observe the expression of homeobox gene Msx-1, Msx-2 and Dlx-2 during murine mandibular first molar development.


METHODS
The murine heads or mandibles on embryonic days 11-18 (E11-18) and postnatal day 1-3 (P1-3) were removed, fixed and embedded, 5 micro m serial sections were cut in the coronal plane. Msx-1, Msx-2 and Dlx-2 RNA probes were synthesized by in vitro transcription and labeled with digoxigenin. Msx-1, Msx-2 and Dlx-2 mRNA expression was observed after in situ hybridization.


RESULTS
During molar development Msx-1 transcripts appeared only in mesenchymal cells, not in epithelial cells. Msx-2 and Dlx-2 both expressed in the epithelial and mesenchymal cells. At the initiation stage of the molar development Msx-2 and Dlx-2 had similar expression. At the bud stage (E13-14) Msx-2 mRNA signaling was intensive in the enamel organ and slight in the dental mesenchyme; Dlx-2 signaling was stronger in the dental papilla. At cap stage (E15-16) Msx-2 showed prominent mRNA signaling in enamel knot and Dlx-2 was maximal in the dental papilla. At the late bell stage (P2-3) Msx-2 transcripts were observed in odontoblasts but not labeled in ameloblasts, and Dlx-2 transcripts appeared in ameloblasts but no labeling was seen in odontoblasts.


CONCLUSIONS
Msx-1, Msx-2 and Dlx-2 are expressed in various patterns during murine mandibular first molar development, suggesting they possibly play a role in the interaction between the epithelium and mesenchyme during the molar development.
Ma
Li
L
Department of Pediatric Dentistry, School of Stomatology, Wuhan University, Wuhan 430079, China.
Chen
Zhi
Z
Song
Guang-tai
GT
Fan
Ming-wen
MW
Zhang
Qi
Q
Wang
Zhi-feng
ZF
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics*; D051957:MSX1 Transcription Factor; D008297:Male; D008334:Mandible / Q000196:embryology*; D051379:Mice; D008963:Molar / Q000196:embryology*; D012333:RNA, Messenger / Q000032:analysis; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; C088334:Distal-less homeobox proteins; D018398:Homeodomain Proteins; D051957:MSX1 Transcription Factor; C084119:MSX2 protein; D012333:RNA, Messenger; D014157:Transcription Factors