Proteolysis on maturing enamel surface, as shown by gel-coating methods
Proteolysis on maturing enamel surface, as shown by gel-coating methods
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DOI：
10.1111/j.1600-0722.2006.00295.x
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发表时间：
2006-05-01
影响因子：
1.9
通讯作者：
Terashima, Tatsuo
中科院分区：
文献类型：
--
作者：
Takano, Yoshiro;Nakano, Yukiko;Terashima, Tatsuo
釉质基质蛋白的降解及其在早期成熟过程中的去除对釉质成熟过程中大釉质晶体的生长至关重要。在这项研究中，我们试图用体内酶谱法来证明成熟珐琅质中蛋白质水解的确切位点及其与上盖成釉细胞的关系。对大鼠和牛门牙成熟的牙釉质表面进行暴露，用预暴露的放射自显像乳剂或密集荧光素共轭（DQ）明胶涂漆。几个小时后，乳剂的照相显影显示成熟的牙釉质表面上黑白相间的条纹图案。DQ明胶也显示出类似的荧光区和非荧光区条带模式。乳剂的白色粉状区域和DQ明胶的荧光带都与褶边端成釉细胞的区域相对应，至少在牙釉质成熟的中期是如此，这表明褶边端成釉细胞在牙釉质基质蛋白的降解中起着主要作用。在牛和大鼠门牙成熟后期，乳剂中的粉状白色带从褶边端转移到光滑端成釉细胞区域，并且不受蛋白酶抑制剂或热失活的影响，暗示非酶相互作用。事实上，DQ明胶在这种末端光滑的成釉细胞区域没有产生任何荧光。
Degradation of enamel matrix proteins, and their removal during early maturation, is critical for the growth of large enamel crystals in the subsequent processes of enamel maturation. In this study, we sought to demonstrate, using in vivo zymography, the exact sites of proteolysis in maturing enamel and its relationship to the overlying ameloblasts. The maturing enamel surfaces of rat and bovine incisors were exposed and painted either with pre-exposed autoradiographic emulsion or with densely fluorescein-conjugated (DQ) gelatin. After a few hours, photographic development of the emulsion revealed alternate black and white banding patterns over the maturing enamel surface. DQ gelatin also revealed similar banding patterns of fluorescent and non-fluorescent regions. White, powdery areas of emulsion and fluorescent bands of DQ gelatin both corresponded to the areas of ruffle-ended ameloblasts, at least up to the mid stages of enamel maturation, implicating a predominant contribution of ruffle-ended ameloblasts in the degradation of enamel matrix proteins. Powdery white bands in autoradiographic emulsion shifted from the areas of ruffle-ended to smooth-ended ameloblasts in late maturation in both bovine and rat incisors and were not influenced by proteinase inhibitors or heat inactivation, implicating non-enzymatic interactions. DQ gelatin, in fact, did not generate any fluorescence in such smooth-ended ameloblast regions.