Haegel H, Larue L, Ohsugi M, Fedorov L, Herrenknecht K, Kemler R
Max-Planck-Institut für Immunbiologie, Freiburg, Germany.
Development. 1995 Nov;121(11):3529-37. doi: 10.1242/dev.121.11.3529.
Molecular analysis of the cadherin-catenin complex elucidated the central role of beta-catenin in this adhesion complex, as it binds to the cytoplasmic domain of E-cadherin and to alpha-catenin. beta-Catenin may also function in signalling pathways, given its homology to the gene product of the Drosophila segment polarity gene armadillo, which is known to be involved in the wingless signalling cascade. To study the function of beta-catenin during mouse development, gene knock-out experiments were performed in embryonic stem cells and transgenic mice were generated. beta-Catenin null-mutant embryos formed blastocysts, implanted and developed into egg-cylinder-stage embryos. At day 7 post coitum, the development of the embryonic ectoderm was affected in mutant embryos. Cells detached from the ectodermal cell layer and were dispersed into the proamniotic cavity. No mesoderm formation was observed in mutant embryos. The development of extraembryonic structures appeared less dramatically or not at all affected. Our results demonstrate that, although beta-catenin is expressed rather ubiquitously, it is specifically required in the ectodermal cell layer.
钙黏蛋白 - 连环蛋白复合体的分子分析阐明了β - 连环蛋白在这种黏附复合体中的核心作用，因为它与E - 钙黏蛋白的胞质结构域以及α - 连环蛋白结合。鉴于β - 连环蛋白与果蝇节段极性基因犰狳的基因产物具有同源性，而后者已知参与无翅信号级联反应，所以β - 连环蛋白也可能在信号通路中发挥作用。为了研究β - 连环蛋白在小鼠发育过程中的功能，在胚胎干细胞中进行了基因敲除实验并培育出了转基因小鼠。β - 连环蛋白基因敲除突变体胚胎形成了囊胚，着床并发育成卵圆柱期胚胎。在交配后第7天，突变体胚胎的胚胎外胚层发育受到影响。细胞从外胚层细胞层脱离并分散到羊膜腔中。在突变体胚胎中未观察到中胚层形成。胚外结构的发育受影响程度较小或根本未受影响。我们的结果表明，尽管β - 连环蛋白的表达相当普遍，但它在外胚层细胞层中是特异性必需的。
