Histo- & cytochemical study of endogenous lectin

众所周知，凝集素是糖类结合蛋白或糖蛋白的非免疫来源。在组织化学和细胞化学中，标记凝集素已被广泛用作检测碳水化合物的探针。利用外源性给药凝集素，糖缀合物在发育、衰老、恶性转化和变性过程中的变化已经成功地原位可视化。凝集素结合模式的可视化不仅可以通过传统的光学显微镜和电子显微镜实现，还可以通过激光共聚焦扫描显微镜以及高压透射电镜和背散射扫描电子成像的结合来实现。近年来，除了上述所谓的“外源性凝集素”外，“内源性凝集素”，特别是动物凝集素也受到了很多关注，特别提到了它们的表达和可能的作用。在脊椎动物中，β-半乳糖结合凝集素已经从不同动物的多种组织中分离出来。例如，小鸡胚胎至少有两种不同的凝集素，14- kd和16-kD凝集素，它们属于动物金属独立凝集素家族或s型，存在于分化的小鸡皮肤中。克隆了这些凝集素的cDNA和基因组DNA，确定了其核苷酸序列和完整的氨基酸序列。免疫组化结果显示，这两种分离素在鸡胚胎跖骨皮肤的体内和体外发育过程中表皮和真皮的表达发生了变化。特别是在体外实验中，如视黄醇诱导的粘膜化生，14、16-kD凝集素之间的差异是明显的。这些隔离素的表达变化与原位杂交信号的变化是平行的。14- kd凝集素和16-kD凝集素在皮肤分化过程中都发挥着重要作用，并且这两种凝集素的基因表达是独立调控的。我们已经检测了内源性14-kD凝集素在正常人皮肤中的定位，以及16-kD和32-kD凝集素在发育中的秀丽隐杆线虫中的定位。此外，我们研究了巨噬细胞半乳糖/ n-乙酰半乳糖-特异性c型凝集素在正常小鼠组织中的表达，发现其在不同发育阶段的位置也有所不同。内源性动物凝集素及其补充糖被认为在细胞和组织中起着基本和关键的作用。结合外源性和内源性凝集素，凝集素的组织化学和细胞化学应该有助于原位阐明糖缀合物的功能和意义。少

As is well known, lectins are carbohydrate-binding proteins or glycoproteins of non-immune origin. In histochemistry and cytochemistry, labeled lectins have been widely used as a probe for the detection of carbohydrates. With the use of exogenously administered lectins, changes in glycoconjugates during the course of development, aging malignant transformation and degeneration have been successfully visualized in situ. Visualization of lectin binding pattern can be achieved not only by conventional light and electron microscopy but also by employing confocal laser scanning microscope and a combination of high voltage transmission electron microscopy and backscattered scanning electron imaging.Recently, in addition to so-called "exogenous lectins" as above, much attention has been paid to "endogenous lectins", in particular, animal lectins, with special reference to their expression and also possible roles.In vertebrates, β-galactoside-binding lectins, galectins, have been isolated from … More several tissues of different animals. Chick embryos, for example, have at least two different kinds of galectins, the 14- and 16-kD lectins, which belong to the family of animal metal-independent lectins or S-type, and exist in differentiating chick skin. Both cDNA and genomic DNA for these galectins were cloned, and the nucleotide sequence as well as the complete amino acid sequence were determined. Immunohistochemically these two isolectins revealed changes in expression in the epidermis and dermis of chick embryonic tarsometatarsal skin during the course of development both in vivo and in vitro. Differences between the 14, and 16-kD lectins were obvious particularly in in vitro experiments such as in retinol-induced mucous metaplasia. Changes in expression of these isolectins were in parallel with those in in situ hybridization signals. Both 14- and 16-kD galectins should play an important role in differentiation of the skin, and the gene expression of these two lectins is regulated independently.We already examined the localization of an endogenous 14-kD galectin in normal humall skin, and the 16-kD and the 32-kD galectins in the developing nematode Caenorhabditis elegans. Besides, we investigated expression of macrophage galactos/N-acetylgalactosamin-specific C-type lectin in normal mouse tissues and found that its location varied at different stages of development as well.Endogenous animal lectins and their complementary sugars have been round to be involved in fundamental and key roles playing in cells and tissues. In combination with both of the exogenous and endogenous lectins, the lectin histo- and cytochemistry should contribute much in elucidation in situ of function and significance or glycoconjugates. Less