牙本质基质蛋白1（DMP1）是在骨基质中高表达的调节骨发育和矿化的重要细胞外基质蛋白。我们的前期研究证实，经过蛋白的体内翻译后修饰过程，DMP1的两个活化片段之一DMP1-N片段具有了蛋白聚糖（PG）的特性，既DMP1-PG。进一步研究发现，DMP1-PG这种蛋白聚糖主要表达在类骨质和矿化不良的骨基质中，而且在矿化缺陷/佝偻病小鼠骨基质内表达明显增加。为了阐述DMP1-PG的生物学功能，我们将从体外和体内两个角度进行分析：（1）观察DMP1-PG对前成骨细胞和骨髓间充质干细胞增殖分化的影响；（2）调节DMP1-PG表达是否影响上述细胞的成骨能力；（3）通过建立DMP1-PG糖基化位点S89突变的小鼠，体内阻断DMP1糖基化的进程，观察缺失DMP1-PG后，小鼠颌骨和长骨发育的变化，并探索其相关机制。通过上述研究，阐述DMP1-PG这种骨基质中新发现的蛋白聚糖在骨发育中的重要作用。

Dentin matrix protein 1 is one kind of highly expressed matrix protein during osteogenesis and bone mineralization.Based on our previous findings, one of DMP1 fragments is modified to be a proteoglycan after post translational modification.We named it as DMP1-PG. This protein fragment,DMP1-PG, is highly expressed in the matrix of newly formed bone and unmature bone matrix. It is interesting that it is extramly incressed in the bone of rickets mice. To explain the role of DMP1-PG in osteogenesis. We will analysis the functions of this proteins in vivo and in vitro:(1) Test the effects of DMP1 on the cell proliferation and differentiation of pre-osteoblast cells and bone marrow stem cells;(2) Whether adjusting the expression level of DMP1 could changing the cell ability of osteogenesis; (3)To block the glycosylation of DMP1, we will set up a mouse model with a PG-site-mutation, and DMP1-PG could not be identified in these mice.We will observe the phenotypic change of mandible and long bone of the mutant mice, and try to explain the mechanism. Based on above works, we will try explain the role of DMP1-PG in osteogenesis and bone mineralization.