人牙髓干细胞是牙髓组织中间充质来源的干细胞，在收到刺激后分化为成牙本质细胞样细胞，形成修复性牙本质保护牙髓。这一过程受多种信号分子及通路调控，其具体机制尚不清楚。申请人前期研究分离并鉴定了人牙髓干细胞，并发现RNA结合蛋白Quaking（QKI）可以促进人牙髓干细胞向成牙本质细胞样细胞分化。免疫沉淀实验显示QKI蛋白可以与DSPP结合。因此我们提出QKI可以通过调控DSPP基因的可变剪接来促进分化过程。本课题拟利用RNA-seq检测人牙髓干细胞分化前后差异表达的基因谱，分析其存在的可变剪接行为。将可变剪接的基因与QKI结合位点对照，获得QKI调控的可变剪接基因谱。进一步证实在分化过程中存在QKI对DSPP基因的可变剪接调控，并在细胞及动物水平探索QKI及该通路对人牙髓干细胞分化的作用。本项目研究成果将对阐明人牙髓干细胞分化具有重要意义，为研究成牙本质细胞分化的机制提供新思路和新方向。

Human dental pulp stem cells (hDPSCs) are mesenchymal stem cells in dental pulp. The odontoblastic differentiation of hDPSCs is essential for the formation of reparative dentin after dental caries or injury, which is regulated by multiples of molecular mechanisms in different expression levels. However, the exact mechanism remains unknown. Our previous study found that the RNA-binding protein QKI was up-regulated during the odontoblastic differentiation of hDPSCs. Knockdown of QKI was able to inhibit the differentiation, which illustrated that QKI was able to promote odontoblastic differentiation. The RIP experiments implied that QKI could bind on DSPP. Thus, we raise that QKI can modulate this process by regulating the alternative splicing of DSPP. This project is proposed to detect functions of QKI in the odontoblastic differentiation of hDPSCs. RNA-seq is used to detect the differentially expressed genes, analyzing the possible alternative splicing events that exist during differentiation. The functional analysis is drawn and DSPP regulated by QKI-reduced alternative splicing is found. More experiments will be performed in odontoblastic differentiation to verify the alternative splicing in cells and its functions. The results of this project will be of great significance to elucidate the differentiation mechanism of hDPSCs and provide new sights and directions for the study of the mechanism of odontoblastic differentiation.