Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan.
Sci Rep. 2020 Mar 20;10(1):5132. doi: 10.1038/s41598-020-61950-y.
The transforming growth factor β (TGF-β) signaling pathway is evolutionarily conserved and widely used in the animal kingdom to regulate diverse developmental processes. Prior studies have shown that Baboon (Babo), a Drosophila type I TGF-β receptor, plays essential roles in brain development and neural circuit formation. However, the expression pattern for Babo in the developing brain has not been previously reported. We generated a knock-in fly with a human influenza hemagglutinin (HA) tag at the C-terminus of Babo and assessed its localization. Babo::HA was primarily expressed in brain structures enriched with neurites, including the mushroom body lobe and neuropils of the optic lobe, where Babo has been shown to instruct neuronal morphogenesis. Since the babo 3' untranslated region contains a predicted microRNA-34 (miR-34) target sequence, we further tested whether Babo::HA expression was affected by modulating the level of miR-34. We found that Babo was upregulated by mir-34 deletion and downregulated by miR-34 overexpression, confirming that it is indeed a miR-34 target gene. Taken together, our results demonstrate that the babo fly permits accurate visualization of endogenous Babo expression during brain development and the construction of functional neural circuits.
转化生长因子β（TGF-β）信号通路在进化上是保守的，广泛用于调节动物王国中的各种发育过程。先前的研究表明，狒狒（Babo），一种果蝇 I 型 TGF-β受体，在大脑发育和神经回路形成中发挥着重要作用。然而，Babo 在发育中的大脑中的表达模式尚未被报道。我们生成了一种带有人类流感血凝素（HA）标签的 knock-in 果蝇，位于 Babo 的 C 末端，并评估了其定位。Babo::HA 主要在富含神经突的脑结构中表达，包括蘑菇体叶和视神经叶的神经网，在这些结构中，Babo 被证明指导神经元形态发生。由于 babo 3'非翻译区包含一个预测的 microRNA-34（miR-34）靶序列，我们进一步测试了调节 miR-34 水平是否会影响 Babo::HA 的表达。我们发现，mir-34 缺失可上调 Babo::HA 的表达，而 miR-34 过表达则下调其表达，证实它确实是 miR-34 的靶基因。总之，我们的结果表明， babo 蝇允许在大脑发育和功能神经回路的构建过程中准确地可视化内源性 Babo 的表达。
