Expression pattern of Sox2 during mouse tooth development.

The transcription factor Sox2 plays important roles in maintaining the pluripotency of embryonic stem cells and adult progenitors. However, whether Sox2 is involved in odontogenesis has not been reported. In this study, we examined the expression pattern of Sox2 during mouse incisor and molar development using real-time PCR, in situ hybridization and immunohistochemistry. Sox2 mRNA was expressed in the dental epithelium and mesenchyme while Sox2 protein was mainly detected in the epithelium from embryonic day (E) 11.5 to postnatal (PN) day 20. In the case of incisor, Sox2 mRNA and protein were expressed in most of dental epithelial cells from E11.5 to E14.5, and they were both highly expressed in the labial cervical loop area from E16.5 to PN20. During molar development, we observed an asymmetrical distribution of Sox2 protein in the epithelium from E13.5 to E16.5, with stronger signals in the lingual side. From E18.5 to PN2, Sox2 was expressed within the cervical loop area, and the stellate intermediate layer. From PN6 to PN14, Sox2 expression was confined mainly to the apical end of hertwig's epithelium root sheath (HERS) cells. Sox2 was also detected within the perivascular region of the dental pulp at PN14 and PN20. Our results suggested that: (1) Sox2 was involved in mouse odontogenesis, and (2) it might participate in maintaining the pluripotency of the epithelial stem cells of labial cervical loop in mouse incisor development and the epithelium progenitors during molar development, (3) Sox2 might be regulated at post-transcription level during mouse odontogenesis.