Decapentaplegic (Dpp), the Drosophila homolog of the vertebrate bone morphogenetic protein (BMP2/4), is crucial for patterning and growth in many developmental contexts. The Dpp pathway is regulated at many different levels to exquisitely control its activity. We show that bantam (ban), a microRNA, modulates Dpp signaling activity. Over expression of ban decreases phosphorylated Mothers against decapentaplegic (Mad) levels and negatively affects Dpp pathway transcriptional target genes, while null mutant clones of ban upregulate the pathway. We provide evidence that dpp upregulates ban in the wing imaginal disc, and attenuation of Dpp signaling results in a reduction of ban expression, showing that they function in a feedback loop. Furthermore, we show that this feedback loop is important for maintaining anterior-posterior compartment boundary stability in the wing disc through regulation of optomotor blind (omb), a known target of the pathway. Our results support a model that ban functions with dpp in a negative feedback loop.

十足瘫痪（Dpp）是脊椎动物骨骼形态发生蛋白（BMP2 / 4）的果蝇同源物，在许多发育环境中对于模式形成和生长至关重要。Dpp途径被调节在许多不同的水平上，以精确地控制其活性。我们显示矮脚鸡（ban），一种microRNA，可调节Dpp信号传导活性。禁令的过度表达降低了磷酸化母亲对抗十足瘫痪（Mad）的水平，并对Dpp途径的转录靶基因产生了负面影响，而禁令的无效突变体克隆则上调了该途径。我们提供的证据表明，dpp上调了机翼假想盘中的禁令，而Dpp信号的衰减导致Dpp信号减少。禁止表达，表明它们在反馈循环中发挥作用。此外，我们表明，该反馈回路对于通过调节光致盲（omb）（该途径的已知靶标）来维持翼片中前后舱室边界的稳定性很重要。我们的结果支持一个模型，该模型禁止在负反馈循环中使用dpp功能。