Baba Otto, Qin Chunlin, Brunn Jan C, Wygant James N, McIntyre Bradley W, Butler William T
Department of Endodontics and Periodontics, The University of Texas-Houston Health Science Center Dental Branch, 6516 M.D. Anderson Boulevard, DBB Rm 375, Houston, TX 77030, USA.
Matrix Biol. 2004 Oct;23(6):371-9. doi: 10.1016/j.matbio.2004.07.008.
Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) are acidic proteins found in the extracellular matrices of bones and teeth. Recent data from gene knockouts, along with those of gene mutations, indicate that these two phosphoproteins are critical for bone and tooth development and/or maintenance. However, the precise functions of the two proteins have not been elucidated. In order to gain insights into their functions in tooth formation, we performed systematic, comparative investigations on the immunolocalization of DMP1 and dentin sialoprotein (DSP, a cleaved fragment of DSPP), using the rat first molar at different developmental stages as a model. Immunohistochemistry (IHC) was performed with specific, monoclonal antibodies against the COOH-terminal fragments of DMP1 and against DSP. In 1-day- and 1-week-old rats, weak immunoreactions for DMP1 were observed in dentinal tubules while stronger reactions for DSP were seen in the tubules and predentin. In rats older than 2 weeks, immunoreactions for DMP1 were found in dentinal tubules, predentin and odontoblasts. In 5-week- and 8-week-old rats, strong immunoreactions for DMP1 were widely distributed in odontoblasts and predentin. The distribution pattern of DSP was strikingly similar to that of DMP1 after 2 weeks and the localization of each was distinctly different from that of bone sialoprotein (BSP). The unique colocalization of DMP1 and DSPP in tooth development suggests that the two proteins play complementary and/or synergistic roles in formation and maintenance of healthy teeth.
牙本质基质蛋白1（DMP1）和牙本质涎磷蛋白（DSPP）是在骨骼和牙齿的细胞外基质中发现的酸性蛋白。来自基因敲除以及基因突变的最新数据表明，这两种磷蛋白对于骨骼和牙齿的发育及/或维持至关重要。然而，这两种蛋白的确切功能尚未阐明。为了深入了解它们在牙齿形成中的功能，我们以大鼠第一磨牙在不同发育阶段为模型，对DMP1和牙本质涎蛋白（DSP，DSPP的裂解片段）的免疫定位进行了系统的比较研究。使用针对DMP1的COOH末端片段和DSP的特异性单克隆抗体进行免疫组织化学（IHC）检测。在1日龄和1周龄的大鼠中，在牙本质小管中观察到DMP1的弱免疫反应，而在小管和前期牙本质中观察到DSP的较强反应。在2周龄以上的大鼠中，在牙本质小管、前期牙本质和成牙本质细胞中发现了DMP1的免疫反应。在5周龄和8周龄的大鼠中，DMP1的强免疫反应广泛分布于成牙本质细胞和前期牙本质中。2周后DSP的分布模式与DMP1的极为相似，且二者的定位均与骨涎蛋白（BSP）明显不同。DMP1和DSPP在牙齿发育中的独特共定位表明，这两种蛋白在健康牙齿的形成和维持中发挥互补和/或协同作用。
