Figure 2. Immunohistochemistry of the mouse dental cell lines with amelogenin exons 8 and 9 antibody. Panels A & B show low (A) and high (B) magnification of ameloblast cells MEOE-3M. Panel C shows low magnification of odontoblast cells MO6-G3. Panel D shows negative control in MO6-G3 cells. Bars: 62.5 µm (A); 31.25 µm (C); 15.625 µm (B, D). Immunohistochemistry of mouse developing tooth organs showed the developmental pattern of amelogenin exons 8 and 9 encoded peptide. Panels E-G show positive staining within the ameloblast (AM), odontoblasts (OD), and stratum intermedium cells (SI). Pre-odontoblasts (pOD; panel E) and mature odontoblasts (panels I-M) were devoid of staining. SI staining was down-regulated (panel G, black arrow) concomitant with the maturation stage of ameloblasts (G). Note the high expression of amelogenin in secretory ameloblasts (F), in contrast to the negative expression in maturation ameloblasts (I–M). Panels I-M show intense biphasic positive staining in the enamel (E). Enamel staining is mainly observed near the dentin-enamel junction and in the newly formed matrix (panel J, black arrows). Enamel staining is clearly diminished near the cemento-enamel junction (M; black arrow). No staining was seen within the dentin (D) or dental pulp cells (DP). Bars: 62.5 µm (I); 25 µm (H,L,M); 15.625 µm (E-G); 12.5 µm (J, K). Panel H shows negative control after primary antibody omission.