Lecuit T, Cohen S M
European Molecular Biology Laboratory, Meyerhofstr. 1, Germany.
Development. 1998 Dec;125(24):4901-7. doi: 10.1242/dev.125.24.4901.
Axis formation in the Drosophila wing depends on the localized expression of the secreted signaling molecule Decapentaplegic (Dpp). Dpp acts directly at a distance to specify discrete spatial domains, suggesting that it functions as a morphogen. Expression levels of the Dpp receptor thick veins (tkv) are not uniform along the anterior-posterior axis of the wing imaginal disc. Receptor levels are low where Dpp induces its targets Spalt and Omb in the wing pouch. Receptor levels increase in cells farther from the source of Dpp in the lateral regions of the disc. We present evidence that Dpp signaling negatively regulates tkv expression and that the level of receptor influences the effective range of the Dpp gradient. High levels of tkv sensitize cells to low levels of Dpp and also appear to limit the movement of Dpp outside the wing pouch. Thus receptor levels help to shape the Dpp gradient.
果蝇翅膀中的轴形成依赖于分泌型信号分子“五体不全”（Dpp）的局部表达。Dpp直接在一定距离外起作用，以指定离散的空间域，这表明它作为一种形态发生素发挥作用。Dpp受体“粗脉”（tkv）的表达水平在翅成虫盘的前后轴上并不均匀。在翅囊中，当Dpp诱导其靶标“条纹”（Spalt）和“眼缺失”（Omb）时，受体水平较低。在成虫盘外侧区域，离Dpp源较远的细胞中，受体水平升高。我们提供的证据表明，Dpp信号传导对tkv表达具有负调控作用，并且受体水平影响Dpp梯度的有效范围。高水平的tkv使细胞对低水平的Dpp敏感，并且似乎还限制了Dpp在翅囊外的移动。因此，受体水平有助于塑造Dpp梯度。
