Division in Anatomy and Developmental Biology, Department of Oral Biology, Taste Research Center, Oral Science Research Center, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul, Korea.
NGeneS Inc., Ansan-si, Korea.
J Dent Res. 2023 Jul;102(7):825-834. doi: 10.1177/00220345231167769. Epub 2023 May 29.
The enamel knot (EK), located at the center of cap stage tooth germs, is a transitory cluster of nondividing epithelial cells. The EK acts as a signaling center that provides positional information for tooth morphogenesis and regulates the growth of tooth cusps. To identify species-specific cuspal patterns, this study analyzed the cellular mechanisms in the EK that were related to bone morphogenetic protein (Bmp), which plays a crucial role in cell proliferation and apoptosis. To understand the cellular mechanisms in the EK, the differences between 2 species showing different cuspal patterning, mouse (pointy bunodont cusp) and gerbil (flat lophodont cusp), were analyzed with quantitative reverse transcriptase polymerase chain reaction and immunofluorescent staining. Based on these, we performed protein-soaked bead implantation on tooth germs of the 2 different EK regions and compared the cellular behavior in the EKs of the 2 species. Many genes related with cell cycle, cell apoptosis, and cell proliferation were involved in BMP signaling in the EK during tooth development. A comparison of the cell proliferation and apoptosis associated with Bmp revealed distinctive patterns of the cellular mechanisms. Our findings indicate that the cellular mechanisms, such as cell proliferation and apoptosis, in the EK are related to Bmp4 and play an important role in tooth morphogenesis.
釉结（EK）位于帽状期牙胚的中心，是一群暂不分裂的上皮细胞。EK 充当信号中心，为牙齿形态发生提供位置信息，并调节牙尖的生长。为了确定具有物种特异性的牙尖模式，本研究分析了与骨形态发生蛋白（Bmp）相关的 EK 中的细胞机制，Bmp 在细胞增殖和细胞凋亡中发挥着关键作用。为了了解 EK 中的细胞机制，我们分析了表现出不同牙尖模式的两种物种（小鼠（尖形布龙都尖）和沙鼠（平形骆马尖））之间 EK 的差异，使用定量逆转录聚合酶链反应和免疫荧光染色。在此基础上，我们对两种不同 EK 区域的牙胚进行了蛋白浸泡珠植入，并比较了两种物种 EK 中的细胞行为。许多与细胞周期、细胞凋亡和细胞增殖相关的基因都参与了牙发育过程中 EK 中的 BMP 信号转导。对与 Bmp 相关的细胞增殖和凋亡的比较揭示了细胞机制的独特模式。我们的研究结果表明，EK 中的细胞机制，如细胞增殖和凋亡，与 Bmp4 有关，在牙齿形态发生中发挥着重要作用。
