Alibardi L
Dipartimento di Biologia, University of Bologna, Italy.
Acta Histochem. 2000 Nov;102(4):453-73. doi: 10.1078/0065-1281-00572.
In the stratum granulosum of mammalian epidermis, keratohyalin contains the histidine-rich protein filagrin which determines the aggregation of keratin bundles in terminally differentiating keratinocytes. Among reptiles, the lizard epidermis possesses keratohyalin-like granules during a period preceding molting. Tritiated histidine is taken up at 3-22 h post-injection mainly in keratohyalin-like granules of the clear layer, and less intensely in oberhautchen cells, in pre-keratinizing cells of wound epidermis and in the alpha-layer. No labelling was observed in beta-cells and mesos cells. Single and double immunogold localization of filagrin and keratin, using mammalian antibodies, show that some filagrin-like immunoreactivity is localized in 0.15-0.40 microm diameter roundish keratohyalin-like granules in cells of wound epidermis, and lacunar and clear layers (soft alpha-layers). Pro-filagrin was not immuno-localized in these layers with the mammalian antibodies. The small granules merge with keratin bundles into mature keratinocytes where immunopositive keratin filaments predominate and the filagrin-like immunolabelling rapidly disappears. Little or no labelling is observed in the large keratohyaline-like granules of the clear layer. This may be due to lack of filagrin-like immunoreactivity but may also be due to epitope-masking or chemical degradation of filagrin-like molecules. No immunoreactivity is present in the beta-layer and mesos-layer but the immunolabelling reappears in the maturing alpha-layer and lacunar layer. This study suggests that histidin-rich protein with some filagrin-like immunoreactivity is initially present in those alpha-layers of lizard epidermis where keratohyalin-like granules are present, such as lacunar and clear cells, and that a filagrin-like molecule is degraded or altered in mature keratinocytes.
在哺乳动物表皮的颗粒层中，透明角质颗粒含有富含组氨酸的蛋白质丝聚合蛋白，它决定了终末分化角质形成细胞中角蛋白束的聚集。在爬行动物中，蜥蜴表皮在蜕皮前的一段时间内具有类透明角质颗粒。注射氚化组氨酸后3 - 22小时，主要在透明层的类透明角质颗粒中摄取，在角质形成前细胞、伤口表皮的前角质形成细胞和α层中摄取较少。在β细胞和中层细胞中未观察到标记。使用哺乳动物抗体对丝聚合蛋白和角蛋白进行单重和双重免疫金定位显示，一些类丝聚合蛋白免疫反应性定位于伤口表皮细胞以及腔隙层和透明层（软α层）中直径为0.15 - 0.40微米的圆形类透明角质颗粒中。前丝聚合蛋白在这些层中未被哺乳动物抗体免疫定位。小颗粒与角蛋白束融合形成成熟的角质形成细胞，其中免疫阳性的角蛋白丝占主导，类丝聚合蛋白免疫标记迅速消失。在透明层的大型类透明角质颗粒中观察到很少或没有标记。这可能是由于缺乏类丝聚合蛋白免疫反应性，但也可能是由于类丝聚合蛋白分子的表位掩盖或化学降解。β层和中层没有免疫反应性，但在成熟的α层和腔隙层中免疫标记重新出现。这项研究表明，具有一些类丝聚合蛋白免疫反应性的富含组氨酸的蛋白质最初存在于蜥蜴表皮的那些存在类透明角质颗粒的α层中，如腔隙细胞和透明细胞，并且类丝聚合蛋白分子在成熟的角质形成细胞中被降解或改变。
