Veis D J, Albinger T M, Clohisy J, Rahima M, Sabsay B, Veis A
J Exp Zool. 1986 Oct;240(1):35-46. doi: 10.1002/jez.1402400106.
The teeth of the sea urchin Lytechinus variegatus grow continuously. The mineral phase, a high magnesium calcite, grows into single crystals within numerous compartments bounded by an organic matrix deposited by the odontoblasts. Electron microscopic examination of glutaraldehyde-fixed Ethylene Diamine Tetra acetic acid (EDTA) demineralized teeth shows the compartment walls to be organized from multiple layers of cell membrane which might contain cytoplasmic protein inclusions. Proteins extracted during demineralization of unfixed teeth were examined by gel electrophoresis, high performance liquid chromatography, and amino acid analysis. The tooth proteins were acidic, they contained phosphoserine, and they were rich in aspartic acid. By contrast, the proteins of similarly extracted mineralized Aristotle's lantern skeletal elements were nonphosphorylated and were rich in glutamic acid. Vertebrate tooth and bone matrix proteins show similar differences. Surprisingly, an antibody to the principle rat incisor phosphoprotein showed a significant cross-reactivity with the urchin tooth protein, by dot-blot and enzyme-linked immunosorbent assay procedures. Thus, the urchin tooth proteins contain epitope regions similar to those which are phenotypic markers of vertebrate odontoblasts. Whether this is an expression of convergent or divergent evolutionary processes, it is likely that the matrix proteins play a similar role in matrix mineralization. The sea urchin tooth may thus be an excellent model for the study of odontoblast-mediated mineral-matrix relationships.
多斑刺冠海胆的牙齿持续生长。其矿物相为高镁方解石，在由成牙本质细胞沉积的有机基质界定的众多小室中生长为单晶。对经戊二醛固定、乙二胺四乙酸（EDTA）脱矿的牙齿进行电子显微镜检查，结果显示小室壁由多层细胞膜组成，这些细胞膜可能含有细胞质蛋白内含物。通过凝胶电泳、高效液相色谱和氨基酸分析对未固定牙齿脱矿过程中提取的蛋白质进行了检测。牙齿蛋白质呈酸性，含有磷酸丝氨酸，且富含天冬氨酸。相比之下，类似提取的矿化亚氏提灯骨骼成分的蛋白质未磷酸化，且富含谷氨酸。脊椎动物的牙齿和骨基质蛋白也表现出类似的差异。令人惊讶的是，通过斑点印迹和酶联免疫吸附测定法，针对大鼠门牙主要磷蛋白的抗体与海胆牙齿蛋白表现出显著的交叉反应性。因此，海胆牙齿蛋白含有与脊椎动物成牙本质细胞的表型标记相似的表位区域。无论这是趋同还是趋异进化过程的表现，基质蛋白在基质矿化中可能发挥类似的作用。因此，海胆牙齿可能是研究成牙本质细胞介导的矿物 - 基质关系的极佳模型。
