腭裂是常见的先天发育缺陷，其分子致病机制尚未研究清楚。小鼠由于腭部发育模式与人类相似，常用于制作腭裂动物模型。研究发现，Osr2基因敲除小鼠因腭间充质细胞增殖减慢而导致腭裂，表明Osr2是调控腭部发育的关键基因。本项目前期构建了Osr2RFP/LacZ基因敲除小鼠，在完全破坏Osr2基因功能的基础上插入RFP标签。通过RNA-seq和ChIP-seq高通量测序发现，细胞粘附分子Cadm3在Osr2基因敲除小鼠的腭间充质细胞中表达量显著下降。体外腭突组织培养挽救实验发现，补偿Cadm3可以挽救Osr2缺失导致的腭裂表型。基于以上发现，本项目利用该小鼠模型，通过分析Osr2在Cadm3基因转录调控区域的结合位点，研究Osr2调控Cadm3基因表达的分子机制；通过分析Cadm3激活的下游分子信号通路，研究Osr2通过Cadm3调控腭间充质细胞增殖的分子机制，为完善腭部发育的分子调控网络奠定基础。

Cleft palate is a common congenital developmental defect in humans. The molecular etiology of the cleft palate remains unknown. The morphogenetic pattern and gene expression of palate is similar between mice and human, thus, it is often used to make the animal model of cleft palate. The knockout of Osr2 gene may lead to cleft palatal due to slow palatal mesenchymal cell proliferation, indicating that Osr2 transcription factor is a key intrinsic regulator of palatogenesis. We first isolated palatal mesenchyme cells from the Osr2RFP/LacZ mutant mouse embryos and performed whole transcriptome RNA-seq and ChIP-seq high-throughput sequencing analyses in the early stage of our project. We found that the expression of cell adhesion molecule Cadm3 in palatal mesenchymal cells of Osr2 knockout mice decreased significantly. In vitro palatal tissue culture rescue experiment confirmed that the compensation of Cadm3 could partially rescue the palatal developmental defects caused by Osr2 deficiency. In this study, we use Osr2RFP/LacZ mouse to study the molecular mechanism of Osr2 regulating Cadm3 expression by analyzing the binding sites of Osr2 in the transcription regulation region of Cadm3. We plan to investigate the downstream signaling pathway molecules activated by Cadm3 and the molecular mechanism of Osr2's regulation of palatal mesenchymal cell proliferation through Cadm3. This project provides a basis for elucidating the molecular regulatory network of palatogenesis.