Histo- & cytochemical study of endogenous lectin

众所周知，凝集素是非免疫性来源的碳水化合物结合蛋白或糖蛋白。在组织化学和细胞化学中，标记的凝集素已被广泛用作检测碳水化合物的探针。随着外源性凝集素的使用，糖结合物在发育、衰老、恶变和退化过程中的变化已经被成功地显示出来。凝集素结合模式的可视化不仅可以通过常规的光学和电子显微镜，而且可以通过激光共聚焦扫描显微镜和高压透射电子显微镜和背散射扫描电子成像相结合的方法来实现。最近，除了上面所说的外源凝集素之外，人们还关注内源性凝集素，特别是动物凝集素，特别是关于它们的表达和可能的作用。在脊椎动物中，β-半乳糖苷结合凝集素，Galectins，已经从…中分离出来更多不同动物的几个组织。例如，鸡胚胎至少有两种不同的半乳凝素，14-和16-kD的凝集素，属于动物金属非依赖性凝集素或S类型的家族，存在于分化的鸡皮中。克隆了半乳糖凝集素的cDNA和基因组DNA，并测定了其核苷酸序列和氨基酸全序列。免疫组织化学显示，在体内和体外发育过程中，这两种异凝素在鸡胚颧骨皮肤的表皮和真皮中的表达发生了变化。在体外实验中，14kD和16kD凝集素之间的差异尤其明显，例如在视黄醇诱导的粘液化生中。这些异凝素的表达变化与原位杂交信号的变化是平行的。14-kD和16-kD Galectins在皮肤分化过程中都起着重要作用，并且这两种凝集素的基因表达是独立调控的。我们已经研究了内源性14-kD Galectin在正常人皮肤中的定位，以及16-kD和32-kD Galectins在线虫发育中的定位。此外，我们还研究了巨噬细胞半乳糖/N-乙酰半乳糖胺特异的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不同。内源性动物凝集素及其互补糖在细胞和组织中发挥着基础和关键的作用。结合外源性和内源性凝集素，凝集素的组织和细胞化学在功能和意义的原位阐明或糖结合物方面将有很大的贡献。较少

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