Fig. 1.

Sox2 expression during incisor morphogenesis. (A) Illustration of mouse incisor development, representing the morphological steps from placode stage to adult. At E14, the dental lingual epithelium gives rise to the lingual cervical loop (liCL), while the labial side originates a larger structure: the labial cervical loop (laCL). The adult laCL is composed of the stellate reticulum (SR), the outer enamel epithelium (OEE) and inner enamel epithelium (IEE). The latter gives rise to the stem cell early progeny, namely the transient-amplifying cells (TA), the stratum intermedium (SI) and the ameloblasts. (B) Sox2 expression (red) is present throughout the entire dental epithelium at E13.5, at highest levels in the lingual side. (C) At P3, Sox2 expression is more sparse, and restricted to the laCL. (D,D′) In adult mice (P60), Sox2 is expressed in the laCL (SR, IEE, OEE and TA cells), as well as in the pre-ameloblasts, ameloblasts (green arrowhead) and SI (red arrowhead). The boxed region in D is magnified in D′. Scale bars: B-D, 100 µm; D′, 50 µm.