Fig. 4.

Deletion of BMP4 in odontoblasts suppresses expression of dentin matrix and dentinal tubule genes: Collagen type I (Col1a1) (B), Osteocalcin (F) and DMP1 (H) in 12–18 day old BMP4 cKO (B, F, H) mice compared to the control (A, E, G). An example in situ hybridization data are shown from various sections from the same set of control and BMP4 cKO animals. All hybridizations have been repeated in independent set of animals with similar results. Here we show quantitation of signal level from this example and shown in Figure 4I. In situ hybridization expression (blue color), in odontoblasts of BMP4 cKO mice, of Col1a1 mRNA (B), Osteocalcin mRNA (F) and DMP1 (H) was reduced by 47%, 68% and 90% as compared to control mice (A, E, G), respectively (I). We noted a 97% reduced mRNA expression in BMP4 cKO mice of DMP1 in cementoblasts (H-cb, red arrows) and of Col1a1 in periodontal osteoblasts (D-ob, orange arrow) compared to the controls (G-cb, purple arrows and C-ob, brown arrows). On the left side of (A through H) surrounded with yellow frame is the smaller magnification of each picture which contains the smaller boxed area representing positions and origins of higher magnifications shown on the right side. d - dentin; od - odontoblasts; pdl - periodontium; p - dental pulp; pdl - periodontium; b - bone; oc - alveolar bone osteocytes; ob - periodontal osteoblasts; cb - cementoblasts.