Main content area

MicroRNA-14 regulates larval development time in Bombyx mori

Liu, Zulian, Ling, Lin, Xu, Jun, Zeng, Baosheng, Huang, Yongping, Shang, Peng, Tan, Anjiang
Insect biochemistry and molecular biology 2018 v.93 pp. 57-65
Bombyx mori, body size, cell lines, ecdysone, ecdysone receptor, gene overexpression, genetic engineering, homeostasis, hormone receptors, invertebrates, larval development, mammals, metamorphosis, microRNA, prediction, pupae, signal transduction, silkworms, transcription (genetics), transgenic animals
MicroRNAs (miRNA) regulate multiple physiological processes including development and metamorphosis in insects. In the current study, we demonstrate that a conserved invertebrate miRNA-14 (miR-14) plays an important role in ecdysteroid regulated development in the silkworm Bombyx mori, a lepidopteran model insect. Ubiquitous transgenic overexpression of miR-14 using the GAL4/UAS system resulted in delayed silkworm larval development and smaller body size of larva and pupa with decrease in ecdysteriod titers. On the contrary, miR-14 disruption using the transgenic CRISPR/Cas9 system led to a precocious wandering stage with increase in ecdysteriod titers. We identified that the hormone receptor E75 (E75) and the ecdysone receptor isoform B (ECR-B), which both serve as essential mediators in the ecdysone signaling pathway, as putative target genes of miR-14 by in silico target prediction. Dual-luciferase reporter assays confirmed the binding of miR-14 to the 3′UTRs of E75 and ECR-B in a mammalian HEK293T cell line. Furthermore, transcription levels of E75 and ECR-B were significantly affected in both miR-14 overexpression and knockout transgenic animals. Taken together, our data suggested that the canonical invertebrate miR-14 is a general regulator in maintaining ecdysone homeostasis for normal development and metamorphosis in B. mori.