Kaltner Herbert, Seyrek Kamel, Heck Andrea, Sinowatz Fred, Gabius Hans-Joachim
Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität, Veterinärstr. 13, 80539 Munich, Germany.
Cell Tissue Res. 2002 Jan;307(1):35-46. doi: 10.1007/s004410100457. Epub 2001 Nov 7.
Histochemical monitoring of developmental processes is presently centered on protein-protein interactions. However, oligosaccharides have the potential to store and transmit biological information. Carbohydrate chains of cellular glycoconjugates present determinants for binding of endogenous lectins. This interaction can be relevant for developmental processes. In fact, beta-galactosides and their derivatives serve as ligands for members of the lectin family of galectins. Since it is unclear to what extent functions of different galectins differ or overlap, hereby introducing redundancy into this system, monitoring of galectin presence during tissue maturation should include more than one type of galectin (galectin fingerprinting). Here, we focus on the two most frequently described ones, namely the homodimeric prototype galectin-1 and the chimera-type galectin-3, the latter one so far not characterized from bovine tissue. In the first step, we have detected its presence biochemically in addition to the abundant galectin-1 in bovine respiratory and digestive tracts during development. Evidently, diversification of the primitive foregut will not lead to an alteration of this property. Immunohistochemistry revealed clear differences in the galectins' localization profiles. Galectin-1 expression is strong in mesenchymal cells, especially smooth muscle cells, while epithelial lining harbors galectin-3. A gradual increase in staining intensity with development is especially observed in the case of galectin-3. Notably, this change is accompanied by a shift from primarily nuclear localization to the cytoplasm, an alteration not seen for galectin-1. However, nuclear presence of galectin-1 is encountered. Thus, the delineation of differences in expression of galectin-1 and -3 with respect to cell types and in the developmental course of subcellular localization argues in favor of mediation of nonoverlapping functions by these two homologous, endogenous lectins.
目前，发育过程的组织化学监测主要集中在蛋白质 - 蛋白质相互作用上。然而，寡糖具有存储和传递生物信息的潜力。细胞糖缀合物的碳水化合物链呈现出内源性凝集素结合的决定因素。这种相互作用可能与发育过程相关。事实上，β - 半乳糖苷及其衍生物作为半乳糖凝集素家族成员的配体。由于尚不清楚不同半乳糖凝集素的功能在何种程度上存在差异或重叠，从而在这个系统中引入了冗余，因此在组织成熟过程中对半乳糖凝集素存在情况的监测应包括不止一种类型的半乳糖凝集素（半乳糖凝集素指纹图谱）。在这里，我们聚焦于两种最常被描述的半乳糖凝集素，即同二聚体原型半乳糖凝集素 -1 和嵌合型半乳糖凝集素 -3，后者迄今为止尚未在牛组织中得到表征。第一步，我们除了在发育过程中的牛呼吸道和消化道中检测到大量的半乳糖凝集素 -1 外，还通过生化方法检测到了它的存在。显然，原始前肠的分化不会导致这种特性的改变。免疫组织化学揭示了半乳糖凝集素在定位模式上的明显差异。半乳糖凝集素 -1 在间充质细胞，尤其是平滑肌细胞中表达强烈，而上皮衬里含有半乳糖凝集素 -3。尤其在半乳糖凝集素 -3 的情况下，随着发育染色强度逐渐增加。值得注意的是，这种变化伴随着从主要核定位向细胞质的转变，而半乳糖凝集素 -1 未见这种改变。然而，也发现了半乳糖凝集素 -1 的核内存在。因此，关于半乳糖凝集素 -1 和 -3 在细胞类型以及亚细胞定位发育过程中的表达差异的描述，支持了这两种同源内源性凝集素介导非重叠功能的观点。
