Analyses of cell recognition mechanisms by genetic manipulation

我们得到了以下结果：1.我们搜索小说。并鉴定了R-钙粘蛋白。这种钙粘附素主要在神经系统表达，但它的表达比Ncadherin出现在发育后期。这些钙粘附素的分布模式也不同。2.以脑mRNA为模板，通过聚合酶链式反应获得了其他新的钙粘蛋白CDNA片段。我们克隆了其中的两个，并测定了它们的序列。这些cDNA编码的钙粘附素显示出一些独特的特征，使它们有别于经典的钙粘附素。这些结果表明，钙粘蛋白家族应该被划分。变成了亚家族。3.尝试用聚合酶链式反应对果蝇钙粘附素进行鉴定，获得了可分为四组的CDNA片段。此外，我们还可以克隆一种脊椎动物的果蝇同源物(x-catenin。4.为了研究钙粘蛋白在胚胎形态发生中的作用，我们将N-钙粘蛋白基因注入非洲爪哇2-细胞期胚胎。N-钙粘附素在胚胎中的过表达导致多种形态异常，包括表皮增厚和细胞团分离。N-钙粘附素的异位表达也影响了一些形态发生运动。这些发现证实了。钙粘附素在形态发生中的调控表达。5.我们证明了连环蛋白是钙粘蛋白相关蛋白，对钙粘蛋白的功能起着至关重要的作用。我们还克隆了cc-catenin，发现它与vinculin相似。

We obtained the following results : 1. We searched for novel. cadherins, and identified R-cadherin. This cadherin was mainly expressed in the nervous system, but its expression occured at later developmental stages than Ncadherin. The distribution patterns of these cadherins were also distinct. 2. By PCR using brain MRNA as template, we obtained other novel cadherin CDNA fragments. We cloned two of them and determined their sequences. Cadherins encoded by these cDNAs showed some unique features which demarcate them from classical cadherins. These results suggest that the cadherin family should be divided. into subfamilies. 3. We attempted to identify Drosophila cadherins using PCR', and could obtain CDNA fragments which can be divided into four groups. Also, we could clone -a Drosophila homologue of vertebrate (x-catenin. 4. To investigate the morphogenetic role of cadherins, we injected N-cadherin mRNA into Xenopus 2-cell stage embryos. The overexpression of N-cadherin in embryos induced various morphological abnormalities, including thickening of epidermis and separation of cell masses. The ectopic expression of N-cadherin also affected some morphogenetic movements. These findings confirmed the importance of. regulated expression of cadherins in morphogenesis. 5. We demonstrated that catenins, cadherin-associated proteins, are crucial for cadherin function. We also cloned cc-catenin, and found that it is similar to vinculin.