DUAL ADHESION MECHANISMS IN EMBRYONIC CHICK TISSUE

优先细胞联合在很大程度上是由以下差异引起的： 细胞粘附特性，结果是， 原则上，属性可以指导细胞的组织， 解剖学上的“正确”结构。 由此推论，这种监管的错误 可能至少部分是恶性肿瘤的转移行为的基础， 细胞和形态发生畸变导致特定的出生缺陷。 对产生细胞的分子机制的详细了解 因此，粘合剂性能对于我们理解各种 形态发生现象 在这方面，这项工作建议 研究前面描述的双重粘附机制的作用， 组织小鸡的视觉系统。 最近生成的单克隆抗体 抑制视网膜Ca++依赖性（CD）聚集的抗体将是 用于识别和分离视网膜CD粘连的成分 机制 如此鉴定的分子将通过分子生物学方法表征。 重量、pI和碳水化合物组成及其与已 鉴定的CD分子（即，CaT，连接素）测定。 在探索 该机制的监管潜力，将努力阐明 Ca++依赖性活性（细胞-细胞结合）的分子基础， 保护蛋白质水解。 为了补充这条线索 还将进行实验，以确定除了 N-CAM有助于视网膜Ca++非依赖性（CI）粘附。 的阵列 抗CD和CI的单克隆和单特异性多克隆抗体 （非CAM）粘附分子然后将用于1）可视化 这些分子在视网膜和其他鸡胚中的分布 2）探索功能性组织之间的结构关系 不同组织中相似的粘附分子，3）研究 CI和CD分子在产生已知的粘附梯度中的作用 视网膜和顶盖，最后4）测试这些在 指导视网膜-顶盖映射。 细胞增殖（速率、选择性） 将使用细胞单层和聚集测定法进行检测。 其他工作 将使用各种电泳技术、蛋白质 印迹、肽图谱、亲和层析、免疫化学和 荧光显微镜

Preferential cell associations arise in large part from differences in cellular adhesive properties with the result that regulation of those properties can in principle guide the organization of cells into anatomically "correct" structures. By corollary, errors in such regulation probably underlie at least in part the metastatic behavior of malignant cells and the morphogenetic aberrations leading to specific birth defects. A detailed knowledge of the molecular mechanisms generating cellular adhesive properties is thus essential to our understanding of diverse morphogenetic phenomena. In that context, this work proposes to investigate the role of the dual adhesion mechanisms described earlier in organizing the chick visual system. Recently generated monoclonals antibodies inhibitory of retinal Ca++ dependent (CD) aggregation will be used to identify and isolate components of the retinal CD adhesion mechanism. The molecules so identified will be characterized by molecular weight, pI and carbohydrate composition and their relationship to already identified CD molecules (ie., CaT, ligatin) determined. In exploring the regulatory potential of this mechanism, efforts will be made to elucidate the molecular basis for Ca++ dependent activity (cell-cell bonding) and protection from proteolysis. To complement this line of investigation experiments will also be performed to determine if molecules other than N-CAM contribute to retinal Ca++ independent (CI) adhesion. An array of monoclonal and monospecific polyclonal antibodies against CD and CI (non-CAM) adhesion molecules will then be used to 1) visualize the distribution of those molecules in the retina and other embryonic chick tissues, 2) to explore the structural relationship between functionally similar adhesion molecules from different tissues, 3) to investigate the role of CI and CD molecules in generating known adhesive gradients across the retina and tectum, and finally 4) to test the role of those in directing retino-tectal mapping. Cellular adhesiveness (rate, selectivity) will be tested using cell monolayer and aggregometer assays. Other work will be performed using various electrophoretic techniques, protein blotting, peptide mapping, affinity chromatography, immunochemistry and fluorescence microscopy.