<p><b>A-B. </b><i>In situ</i> hybridization was performed using AMELX oligonucleotidic probes. <b>B.</b> WT mouse shows strong AMELX mRNA level in ameloblasts (Ambl) and odontoblasts (Odb). AMELX mRNA is also detected in bone-lining cells (red arrows) and, with an apparent lower level, in dental follicle (DF) area. <b>C–D.</b> Immunohistodetection was performed using anti-AMELX antibody. <b>D.</b> AMELX protein expression in WT mouse was detected in ameloblasts, odontoblasts and bone-lining cells (red arrows). Strong and diffuse protein signal was also observed in dental follicle. <b>B–D.</b> No AMELX RNA and protein signal is detected in striated muscle (Myo), a negative control tissue (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0099626#pone-0099626-t001" target="_blank">Table 1</a>). <b>A–C.</b> Neither AMELX mRNA nor protein expression is detected in AMELX KO mice.</p
