Buffering variability in morphogen distribution is essential for reproducible patterning. A theoretically proposed class of mechanisms, termed "distal pinning," achieves robustness by combining local sensing of morphogen levels with global modulation of gradient spread. Here, we demonstrate a critical role for morphogen sensing by a gene enhancer, which ultimately determines the final global distribution of the morphogen and enables reproducible patterning. Specifically, we show that, while the pattern of Toll activation in the early Drosophila embryo is robust to gene dosage of its locally produced regulator, WntD, it is sensitive to a single-nucleotide change in the wntD enhancer. Thus, enhancer properties of locally produced WntD directly impinge on the global morphogen profile.

中文翻译：

---

Toll激活的整体形状由wntD增强子属性决定。

形态发生分布中的缓冲变异性对于可重复的图案形成至关重要。从理论上讲，一类机制被称为“远距钉扎”，它通过将形态发生子水平的局部感测与梯度扩展的整体调制相结合来实现鲁棒性。在这里，我们展示了通过基因增强子对形态发生素感测的关键作用，它最终决定了形态发生素的最终全局分布并实现了可再现的模式。具体来说，我们显示，虽然果蝇早期胚胎中Toll激活的模式对其本地产生的调节子WntD的基因剂量具有鲁棒性，但它对wntD增强子中的单核苷酸变化敏感。因此，局部产生的WntD的增强子特性直接影响全局形态发生子谱。