Fukae M, Tanabe T, Nagano T, Ando H, Yamakoshi Y, Yamada M, Simmer J P, Oida S
Department of Biochemistry, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan.
J Dent Res. 2002 Oct;81(10):668-72. doi: 10.1177/154405910208101003.
The temporal expression patterns and activity distributions of enamelysin and EMSP1, which are the major proteinases in immature enamel, were characterized. Extracellular matrix fractions from developing porcine incisors, individually comprised of predentin, dentin, and four secretory-stage enamel samples, including the highly mineralized enamel (HME) at the enamel-dentin junction (EDJ), were isolated, and their resident proteinases were identified by zymography. Soft-tissue fractions, which included cells from the extension site of enamel formation (ESEF), secretory- and maturation-stage ameloblasts, and odontoblasts, were characterized histologically and by RT-PCR for their expression of enamelysin and EMSP1. A significant finding was that EMSP1, expressed by odontoblasts, concentrates in the HME, but is not detected in predentin or dentin. We conclude that odontoblasts deposit EMSP1 via their cell processes into the deepest enamel layer, which facilitates the hardening of this layer and contributes significantly to the functional properties of the EDJ.
对牙釉质溶解素和EMSP1（未成熟牙釉质中的主要蛋白酶）的时间表达模式和活性分布进行了表征。从发育中的猪切牙中分离出细胞外基质部分，分别由前期牙本质、牙本质以及四个分泌阶段的牙釉质样本组成，包括牙釉质-牙本质交界处（EDJ）的高度矿化牙釉质（HME），并通过酶谱法鉴定其驻留蛋白酶。对软组织部分进行了组织学表征，并通过RT-PCR分析其牙釉质溶解素和EMSP1的表达，软组织部分包括牙釉质形成延伸部位（ESEF）的细胞、分泌期和成长期的成釉细胞以及成牙本质细胞。一个重要发现是，成牙本质细胞表达的EMSP1集中在HME中，但在前牙本质或牙本质中未检测到。我们得出结论，成牙本质细胞通过其细胞突起将EMSP1沉积到最深的牙釉质层中，这有助于该层的硬化，并对EDJ的功能特性有显著贡献。
