Department of Oral Anatomy, Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 500-757, Republic of Korea.
J Mol Histol. 2024 Apr;55(2):149-157. doi: 10.1007/s10735-024-10182-9. Epub 2024 Feb 26.
Cytodifferentiation of odontogenic cells, a late stage event in odontogenesis is based on gene regulation. However, studies on the identification of the involved genes are scarce. The present study aimed to search for molecules for the cytodifferentiation of ameloblastic cells in rats. Differential display-PCR revealed a differentially expressed gene between cap/early bell stage and hard tissue formation stage in molars. This gene was identified as N-myc Downregulated Gene 1 (Ndrg1), which is the first report in tooth development. Real time PCR and western blotting confirmed that the mRNA level of Ndrg1 was higher during enamel formation than the cap stage. Ndrg1 expression was upregulated in the early bell, crown, and root stages in a time-dependent manner. These patterns of expression were similar in Ndrg2, but Ndrg3 and Ndrg4 levels did not change during the developmental stages. Immunofluorescence revealed that strong immunoreactivity against Ndrg1 were detected in differentiated ameloblasts only, not inner enamel epithelium, odontoblasts and ameloblastic cells in defected enamel regions. Alkaline phosphatase and alizarin red s stains along with real time PCR, revealed that Ndrg1 and Ndrg2 were involved in cytodifferentiation and enamel matrix mineralization by selectively regulating amelogenin and ameloblastin genes in SF2 ameloblastic cells. These results suggest that Ndrg may play a crucial functional role in the cytodifferentiation of ameloblasts for amelogenesis.
牙源性细胞的细胞分化是牙发生的晚期事件，基于基因调控。然而，关于涉及基因的研究很少。本研究旨在寻找大鼠成釉细胞细胞分化的分子。差异显示-PCR 显示在磨牙的帽状/早期钟状期和硬组织形成期之间存在差异表达的基因。该基因被鉴定为 N-myc 下调基因 1（Ndrg1），这是在牙齿发育中的首次报道。实时 PCR 和 Western blot 证实，在釉质形成期间，Ndrg1 的 mRNA 水平高于帽状期。Ndrg1 的表达在早期钟状期、冠部和根部呈时间依赖性上调。Ndrg2 的表达模式相似，但 Ndrg3 和 Ndrg4 的水平在发育阶段没有变化。免疫荧光显示，Ndrg1 的强免疫反应性仅在分化的成釉细胞中检测到，而在内釉上皮细胞、成牙本质细胞和成釉细胞缺陷区域中未检测到。碱性磷酸酶和茜素红 S 染色以及实时 PCR 显示，Ndrg1 和 Ndrg2 通过选择性调节 SF2 成釉细胞中的釉原蛋白和釉基质蛋白基因参与细胞分化和釉基质矿化。这些结果表明，Ndrg 可能在成釉细胞的细胞分化中发挥关键功能作用，从而参与釉质形成。
