Fig. 4.

Unaltered expression of enamel matrix proteins and proteases in Dlx3^K14–cKO mice. (A) Schematics illustrating the dissection and isolation of RNA from the enamel organs of continuously growing incisors from mandibles of Dlx3^WT and Dlx3^K14–cKO mice at P10. Arrowheads at the tip of the mandibles point at the just erupted mandibular incisor and mark a stage where all phases of ameloblast differentiation are represented. Lower panel shows visualization of RNA-seq coverage data confirming complete deletion of Dlx3 exons 2 and 3 in the enamel organ in Dlx3^K14–cKO mice. (B) Heat map showing log(RPKM) levels of Dlx3 and major enamel differentiation markers that have been associated with amelogenesis imperfecta, in enamel organs from Dlx3^WT and Dlx3^K14–cKO mice. Except for Dlx3, none of the fold-changes indicated are significant. (C) Western blot analysis of AMELX and MMP20 protein levels in the enamel organ of Dlx3^WT and Dlx3^K14–cKO mice at P10. (D) Immunohistochemical detection of AMELX (green) in mandibular incisor sections from Dlx3^WT and Dlx3^K14–cKO mice. White arrowheads point at ameloblasts, asterisks mark the enamel space. Scale bar: 100 μm. (E) ChIP-seq analysis of DLX3 and H3K4me3 DNA binding domains in enamel organ dissected from rat mandibular incisors (continuously growing), showing DLX3 binding near the proximal promoter (arrowhead marks transcription start site) of Ambn and Mmp20. DM = dental mesenchyme.