Watanabe M, Kobayashi H, Rutishauser U, Katar M, Alcala J, Maisel H
Department of Genetics, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
Dev Biol. 1989 Oct;135(2):414-23. doi: 10.1016/0012-1606(89)90190-5.
The role of the neural cell adhesion molecule (NCAM)2 in ocular lens differentiation was investigated in chicken embryos. Changes in expression of NCAM were documented by immunohistology of frozen sections. This analysis revealed that NCAM diminished during lens fiber differentiation, in contrast to the gap junction-associated protein MP26 which became more abundant. The form of NCAM expressed was determined by Western blot analysis of proteins extracted from the different regions of the Embryonic Day 6 lenses. All regions expressed NCAM with an apparent molecular weight of 140 kDa and relatively low levels of polysialylation. The function of NCAM in lens differentiation was investigated using antibodies that inhibit NCAM-mediated adhesion. Two parameters that change during maturation of the lens epithelial cells were monitored: the thickness of the tissue, indicating the length of lens cells, and the particle arrangement of gap junctions, reflecting the state of junctional differentiation. When epithelial cell explants of Embryonic Day 6 lenses were cultured for 5 days, the cells elongated and displayed an increase in the loose, random intramembranous particle arrangements characteristic of maturing lens fiber gap junctions. When the explants were cultured in the presence of anti-NCAM Fabs, the epithelia were thinner than in matched controls and had particle arrangements characteristic of a less mature state. The expression of NCAM during lens differentiation and the effects of attenuating NCAM function suggest that adhesion mediated by NCAM is an essential event in lens cell differentiation.
在鸡胚中研究了神经细胞黏附分子（NCAM）2在晶状体分化中的作用。通过冷冻切片的免疫组织学记录NCAM表达的变化。该分析显示，与缝隙连接相关蛋白MP26变得更加丰富相反，NCAM在晶状体纤维分化过程中减少。通过对胚胎第6天晶状体不同区域提取的蛋白质进行蛋白质印迹分析，确定了所表达的NCAM的形式。所有区域均表达表观分子量为140 kDa且多聚唾液酸化水平相对较低的NCAM。使用抑制NCAM介导的黏附的抗体研究了NCAM在晶状体分化中的功能。监测了晶状体上皮细胞成熟过程中发生变化的两个参数：组织厚度，表明晶状体细胞的长度；缝隙连接的颗粒排列，反映连接分化状态。当将胚胎第6天晶状体的上皮细胞外植体培养5天时，细胞伸长，并且成熟晶状体纤维缝隙连接特有的松散、随机的膜内颗粒排列增加。当外植体在抗NCAM Fabs存在下培养时，上皮比匹配的对照更薄，并且具有较不成熟状态特有的颗粒排列。NCAM在晶状体分化过程中的表达以及减弱NCAM功能的作用表明，NCAM介导的黏附是晶状体细胞分化中的一个重要事件。
