Partanen A M, Thesleff I
Differentiation. 1987;34(1):18-24. doi: 10.1111/j.1432-0436.1987.tb00046.x.
The iron-transporting serum glycoprotein, transferrin, is necessary for the cell proliferation, morphogenesis, and differentiation of mouse embryonic teeth and kidneys in organ culture. The stimulatory effect of transferrin is mediated by the binding of transferrin to its specific cell-surface receptor and by receptor-mediated endocytosis. Since, in both teeth and kidneys, the requirement for and responsiveness to transferrin depend on the developmental stage of the organ, we studied the binding of transferrin at various stages of tooth and kidney development by incubating tissues with 125I-labeled transferrin. The amount of bound transferrin was determined by measuring the tissue-incorporated radioactivity, and the binding sites were localized by autoradiography. During tooth development in vitro, the requirement for exogenous transferrin is lost as the teeth proceed from the early cap stage to the bell stage. The level of transferrin binding was found to decrease simultaneously, and in bell-stage teeth, the transferrin receptors were concentrated in the areas of most active cell proliferation. In kidneys, the number of transferrin receptors was highest at the stage during which the undifferentiated kidney mesenchyme becomes responsive to transferrin. These receptors were located in both the ureter epithelium and the metanephric mesenchyme, and they dramatically decreased in number with advancing kidney differentiation. The results of the present study indicate that, during the embryonic development of teeth and kidneys, the amount and localization of transferrin binding are correlated with cell proliferation. The number of transferrin receptors is highest during the developmental stages when cell proliferation is most active, and decreases with advancing differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)
铁转运血清糖蛋白转铁蛋白对于器官培养中小鼠胚胎牙齿和肾脏的细胞增殖、形态发生及分化是必需的。转铁蛋白的刺激作用是通过其与特定细胞表面受体的结合以及受体介导的内吞作用来介导的。由于在牙齿和肾脏中，对转铁蛋白的需求和反应性均取决于器官的发育阶段，因此我们通过用¹²⁵I标记的转铁蛋白孵育组织，研究了牙齿和肾脏发育各阶段中转铁蛋白的结合情况。通过测量组织摄取的放射性来确定结合的转铁蛋白量，并通过放射自显影确定结合位点的位置。在体外牙齿发育过程中，随着牙齿从早期帽状期进入钟状期，对外源转铁蛋白的需求消失。发现转铁蛋白结合水平同时降低，在钟状期牙齿中，转铁蛋白受体集中在细胞增殖最活跃的区域。在肾脏中，转铁蛋白受体数量在未分化的肾间充质开始对转铁蛋白产生反应的阶段最高。这些受体位于输尿管上皮和后肾间充质中，随着肾脏分化的推进，其数量显著减少。本研究结果表明，在牙齿和肾脏的胚胎发育过程中，转铁蛋白结合的量和定位与细胞增殖相关。转铁蛋白受体数量在细胞增殖最活跃的发育阶段最高，并随着分化的推进而减少。（摘要截短于250词）
