Kim Hyun-Jin, Kim Young-Ju, Kang Jee-Hae, Jung Ji-Yeon, Kim Min-Seok, Kim Won-Jae, Oh Won-Man, Hwang Yun-Chan, Hwang In-Nam, Choi Nam-Ki, Lee Eun-Ju, Kim Sun-Hun
Department of Oral Anatomy, School of Dentistry, Wonkwang University, Iksan, South Korea.
Eur J Oral Sci. 2008 Oct;116(5):418-23. doi: 10.1111/j.1600-0722.2008.00554.x.
Tooth development occurs through a complex and intricate set of gene-expression cascades. Although its early events have been examined extensively, there are fewer reports on the late events, such as dental hard-tissue formation. This study searched for genes involved in the late stages of tooth development. Differential display-polymerase chain reaction revealed myelin basic protein (MBP) mRNA to be expressed differentially in the second molar root stage germs compared with the third molar cap/early bell stage germs. The MBP expressed during hard tissue formation was confirmed to be a 21.5 kDa molecule by Western blotting. Immunoreactivity of MBP in the third molar (cap/early bell stage) germs was barely detectable in the dental papilla and inner enamel epithelia, whereas strong reactivity was noted in the differentiating and differentiated ameloblasts and odontoblasts in a temporospatial pattern. However, after complete formation of the full-thickness enamel, no reactivity was observed in the maturation-stage and protection stage ameloblasts. Myelin basic protein immunoreactive nerve fibers were also observed near the developing molar germs. This is the first report showing the presence of MBP in dental hard tissue cells, and its functional implications should be studied further.
牙齿发育通过一系列复杂且精细的基因表达级联反应发生。尽管其早期事件已得到广泛研究，但关于后期事件，如牙齿硬组织形成的报道较少。本研究寻找参与牙齿发育后期阶段的基因。差异显示聚合酶链反应表明，与第三磨牙帽状/早期钟状期牙胚相比，髓磷脂碱性蛋白（MBP）mRNA在第二磨牙牙根期牙胚中差异表达。通过蛋白质印迹法证实，在硬组织形成过程中表达的MBP是一个21.5 kDa的分子。在第三磨牙（帽状/早期钟状期）牙胚中，MBP在牙乳头和内釉上皮中的免疫反应性几乎检测不到，而在分化和已分化的成釉细胞及成牙本质细胞中观察到强烈的反应性，且呈时空模式。然而，在全层釉质完全形成后，在成熟阶段和保护阶段的成釉细胞中未观察到反应性。在发育中的磨牙牙胚附近也观察到了髓磷脂碱性蛋白免疫反应性神经纤维。这是首次报道在牙齿硬组织细胞中存在MBP，其功能意义有待进一步研究。
