Henan Key Laboratory of Insect Biology in Funiu Mountain, Henan International Joint Laboratory of Insect Biology, College of Life Science and Agricultural Engineering, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, China.
School of Life Science and Technology, Henan Institute of Science and Technology, 90 East of Hualan Avenue, Xinxiang, Henan 453003, China.
J Insect Sci. 2022 May 1;22(3). doi: 10.1093/jisesa/ieac028.
A number of long noncoding RNAs (lncRNAs) have been identified in silkworm, but little is known about their functions. Recent study showed that the let-7 miRNA cluster (contains let-7, miR-2795, and miR-100) was transcribed from the last exon of lncRNA lncR17454 in silkworm. To investigate the functional role of lncR17454, dsRNAs of lncR17454 were injected into the hemolymph of 1-d-old third-instar larvae of Bombyx mori, repression of lncR17454 led to molting arrestment during the larval-larval and larval-pupal transition of silkworm, which was consistent to the result as let-7 knockdown in other studies. The expression level of mature let-7, miR-100, and miR-2795 decreased 40%, 36%, and 40%, respectively, while the mRNA level of two predicted target genes of let-7, the Broad Complex isoform 2 (BR-C-Z2) and the BTB-Zinc finger transcription repression factor gene Abrupt (Ab), increased significantly after lncR17454 knockdown. In contrast, when adding the 20-Hydroxyecdysone (20E) to silkworm BmN4 cell lines, the expression level of lncR17454 and let-7 cluster all increased significantly, but the expression of Abrupt, the predicted target gene of let-7, was repressed. Dual-luciferase reporter assays confirmed Abrupt was the real target of let-7. Here we found that the lncRNA lncR17454 can play regulator roles in the metamorphosis of silkworm through let-7 miRNA cluster and the ecdysone signaling pathway, which will provide new clues for lepidopteran pest control.
一些长链非编码 RNA（lncRNAs）在蚕中已被鉴定，但它们的功能知之甚少。最近的研究表明，let-7 miRNA 簇（包含 let-7、miR-2795 和 miR-100）是从蚕的长链非编码 RNA lncR17454 的最后一个外显子转录而来的。为了研究 lncR17454 的功能作用，将 lncR17454 的 dsRNA 注入到 1 龄 3 龄幼虫的血淋巴中，lncR17454 的抑制导致蚕幼虫-蛹转变过程中的蜕皮停滞，这与其他研究中 let-7 敲低的结果一致。成熟的 let-7、miR-100 和 miR-2795 的表达水平分别下降了 40%、36%和 40%，而 let-7 的两个预测靶基因 Broad Complex isoform 2 (BR-C-Z2) 和 BTB-Zinc finger transcription repression factor gene Abrupt (Ab) 的 mRNA 水平则显著增加。相反，当向蚕 BmN4 细胞系中添加 20-羟基蜕皮激素（20E）时，lncR17454 和 let-7 簇的表达水平均显著增加，但 let-7 的预测靶基因 Abrupt 的表达受到抑制。双荧光素酶报告基因实验证实 Abrupt 是 let-7 的真正靶基因。在这里，我们发现长链非编码 RNA lncR17454 可以通过 let-7 miRNA 簇和蜕皮激素信号通路在蚕的变态中发挥调节作用，这将为鳞翅目害虫的防治提供新的线索。
