Zalik S E, Didier E, Didier P, Ledsham I M, Bayle D, Sanders E J
Department of Zoology, University of Alberta, Canada.
Int J Dev Biol. 1994 Mar;38(1):55-68.
Early chick embryos contain two beta-galactoside-binding lectins of 16 kDa and 14 kDa. using several antisera to these proteins, we have studied lectin expression at embryonic stages when the segregation and early differentiation of organ primordia are taking place. With antisera to the 16 kDa lectin that display similar immunoreactivity in immunoblot analysis, we show that these antisera exhibit varying immunoreactivity in embryo sections. One antiserum reacts preferentially with a matrix form of lectin while another detects mainly a cellular form of this protein. During early development, galactoside-binding lectins of the matrix type are expressed in the vitelline membrane, the outer and inner limiting membranes of the neural tube, the surface of the notochord and the coelomic surface of the cardiac rudiments. The cellular form of the lectin occurs in the intracellular yolk of early embryos, in the primordial germ cells, the myocardium, in the early myotome, and in a cohort of cells which are presumed to belong to the neural crest. Our results indicate that, although all of the antisera recognize the intracellular lectin of the extraembryonic endoderm, some antisera to the 16 kDa lectin exhibit preferential reactivity with different lectin isoforms. The extracellular matrix form of lectin is transiently expressed during early development at the stages when the segregation of organ primordia is occurring. It's expression could be related to the acquisition of polarity in developing epithelia. Results also suggest that various versions of the same protein may perform distinct developmental roles in the embryo.
早期鸡胚含有两种分子量分别为16 kDa和14 kDa的β-半乳糖苷结合凝集素。我们使用针对这些蛋白质的几种抗血清，研究了在器官原基发生分离和早期分化的胚胎阶段凝集素的表达情况。对于在免疫印迹分析中显示出相似免疫反应性的针对16 kDa凝集素的抗血清，我们发现这些抗血清在胚胎切片中表现出不同的免疫反应性。一种抗血清优先与凝集素的基质形式发生反应，而另一种主要检测到这种蛋白质的细胞形式。在早期发育过程中，基质型半乳糖苷结合凝集素在卵黄膜、神经管的外、内界膜、脊索表面和心脏原基的体腔表面表达。凝集素的细胞形式存在于早期胚胎的细胞内卵黄、原始生殖细胞、心肌、早期肌节以及一群推测属于神经嵴的细胞中。我们的结果表明，尽管所有抗血清都能识别胚外内胚层的细胞内凝集素，但一些针对16 kDa凝集素的抗血清对不同的凝集素同工型表现出优先反应性。凝集素的细胞外基质形式在器官原基发生分离的早期发育阶段短暂表达。它的表达可能与发育中上皮细胞极性的获得有关。结果还表明，同一蛋白质的不同变体可能在胚胎中发挥不同的发育作用。
