Widmann Thomas J, Dahmann Christian
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
Dev Biol. 2009 Oct 1;334(1):161-73. doi: 10.1016/j.ydbio.2009.07.013. Epub 2009 Jul 21.
The control of cell morphology is important for shaping animals during development. Here we address the role of the Wnt/Wingless signal transduction pathway and two of its target genes, vestigial and shotgun (encoding E-cadherin), in controlling the columnar shape of Drosophila wing disc cells. We show that clones of cells mutant for arrow (encoding an essential component of the Wingless signal transduction pathway), vestigial or shotgun undergo profound cell shape changes and are extruded towards the basal side of the epithelium. Compartment-wide expression of a dominant-negative form of the Wingless transducer T-cell factor (TCF/Pangolin), or double-stranded RNA targeting vestigial or shotgun, leads to abnormally short cells throughout this region, indicating that these genes act cell autonomously to maintain normal columnar cell shape. Conversely, overexpression of Wingless, a constitutively-active form of the Wingless transducer beta-catenin/Armadillo, or Vestigial, results in precocious cell elongation. Co-expression of Vestigial partially suppresses the abnormal cell shape induced by dominant-negative TCF. We conclude that Wingless signal transduction plays a cell-autonomous role in promoting and maintaining the columnar shape of wing disc cells. Furthermore, our data suggest that Wingless controls cell shape, in part, through maintaining vestigial expression.
细胞形态的控制对于动物发育过程中的形态塑造至关重要。在此，我们探讨Wnt/Wingless信号转导通路及其两个靶基因——残翅基因（vestigial）和枪虾基因（shotgun，编码E-钙黏蛋白）在控制果蝇翅盘细胞柱状形态方面的作用。我们发现，箭头基因（arrow，编码Wingless信号转导通路的一个必需组分）、残翅基因或枪虾基因发生突变的细胞克隆会经历深刻的细胞形态变化，并被挤压向上皮细胞的基底侧。在整个区域广泛表达无翅信号转导蛋白T细胞因子（TCF/穿山甲）的显性负性形式，或靶向残翅基因或枪虾基因的双链RNA，会导致该区域细胞异常短小，这表明这些基因在细胞自主发挥作用以维持正常的柱状细胞形态。相反，无翅蛋白（Wingless）、无翅信号转导蛋白β-连环蛋白/犰狳（Armadillo）的组成型活性形式或残翅蛋白的过表达会导致细胞过早伸长。残翅蛋白的共表达部分抑制了显性负性TCF诱导的异常细胞形态。我们得出结论，Wingless信号转导在促进和维持翅盘细胞的柱状形态中发挥细胞自主作用。此外，我们的数据表明，Wingless部分通过维持残翅基因的表达来控制细胞形态。
