The Drosophila melanogaster corpus allatum (CA) produces and releases three types of sesquiterpenoid hormones, including juvenile hormone III bisepoxide (JHB3), juvenile hormone III (JH III), and methyl farnesoate (MF). JH biosynthesis involves multiple discrete enzymatic reactions and is subjected to a comprehensive regulatory network including microRNAs (miRNAs). Using a high throughput sequencing approach, we have identified abundant miRNAs in the D. melanogaster ring gland, which consists of the CA, prothoracic gland, and corpus cardiaca. Genetic and qPCR screens were then performed in an attempt to uncover the full repertoire of CA miRNAs that are involved in regulating metamorphosis. miR-8 was identified as a potential candidate and further studied for its role in the CA. Overexpression of miR-8 in the CA increased cell size of the gland and expression of Jhamt (a gene coding for a key regulatory enzyme in JH biosynthesis), resulting in pupal lethality. By contrast, sponge-mediated reduction of miR-8 in the CA decreased cell size and Jhamt expression, but did not cause lethality. Further investigation revealed that miR-8 promotes cell growth independent of insulin/IGF signaling. Taken together, these experiments show that miR-8 is highly expressed in the CA and exerts its positive effects on cell growth and JH biosynthesis. The miRNAs data in the ring gland also provide a useful resource to study how miRNAs collaboratively regulate hormone synthesis in D. melanogaster.

在黑腹果蝇语料库allatum （CA）产生并释放三种类型的倍半萜类的激素，包括幼激素III双环氧化物（JHB3），保幼激素III（JH III）和金合欢酸甲酯（MF）。JH生物合成涉及多个离散的酶促反应，并受到包括 microRNA (miRNA) 在内的综合调控网络的影响。使用高通量测序方法，我们在D. melanogaster环腺中鉴定了丰富的 miRNA ，它由 CA、前胸腺组成，和心体。然后进行遗传和 qPCR 筛选，试图揭示参与调节变态的 CA miRNA 的全部库。miR-8 被确定为潜在的候选者，并进一步研究了它在 CA 中的作用。CA 中 miR-8 的过表达增加了腺体的细胞大小和Jhamt （一种编码 JH 生物合成中的关键调控酶的基因）的表达，导致蛹致死。相比之下，海绵介导的 CA 中 miR-8 的减少减少了细胞大小和Jhamt表达，但没有造成杀伤力。进一步的研究表明，miR-8 促进细胞生长，而不受胰岛素/IGF 信号的影响。总之，这些实验表明 miR-8 在 CA 中高度表达，并对细胞生长和 JH 生物合成发挥积极作用。环腺中的 miRNA 数据也为研究 miRNA 如何协同调节黑腹果蝇中的激素合成提供了有用的资源。