Figure 5: Localization of NUMB in odontogenic tissues at postnatal day 5: NUMB expression can be detected in the ameloblasts and odontoblasts. Notice that in (a1), NUMB is positively stained in some ameloblasts but negatively stained in the adjacent cells (indicated by arrows). Scale bar represents 100 μm for (a); 50 μm for (b); 20 μm for (a1), (a2), and (b1), (b2), respectively.