Location: Biological Control of Insects ResearchTitle: MicroRNA-281 regulates the expression of ecdysone receptor (EcR) isoform B in the silkworm, Bombyx mori Author
Submitted to: Insect Biochemistry and Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2013
Publication Date: 8/1/2013
Citation: Jiang, J., Ge, X., Li, Z., Wang, Y., Song, Q., Stanley, D.W., Tan, A., Huang, Y. 2013. MicroRNA-281 regulates the expression of ecdysone receptor (EcR) isoform B in the silkworm, Bombyx mori. Insect Biochemistry and Molecular Biology. 43(8):692-700. Interpretive Summary: Use of classical insecticides has introduced severe problems in agricultural and environmental sustainability. Two of the most pressing problems are the ability of pest insects to resist classical insecticides and the negative influence of insecticides on ecosystems. One approach to reduce the environmental insecticide load is based on the concept of disrupting insect hormone systems to cripple insect development. This idea grew from discovery that chemicals that naturally occur in a few plant species block insect development. Although this modern approach to insect control is feasible, direct application is problematic. The concept of disrupting insect development is limited by lack of detailed knowledge of insect hormone systems. To help solve this problem, we are investigating how one of the insect hormones influences development. In this paper we report on identification of a specific regulator of hormone effects. We demonstrate the regulation of a specific gene required for development. This new research will be directly useful to scientists who are working to improve the usefulness of disrupting insect development. The ensuing improved methods will benefit a wide range of agricultural producers, and people who rely on agricultural products, by supporting the long-term sustainability of agriculture.
Technical Abstract: Hundreds of Bombyx mori miRNAs had been identified in recent years, but their function in vivo remains poorly understood. The silkworm EcR gene (BmEcR) has three transcriptional isoforms, A, B1 and B2. Isoform sequences are different in the 3’UTR region of the gene, which is the case only in insects. Here we report a conserved miRNA, miR-281, that regulates the BmEcR-B isoforms in vivo with no affect on BmEcR-A. miR-281 is expressed in high levels in Malpighian tubules, silk gland and midgut. Expression of miR-281 decreased from a peak during the L4 molt to a low level in pupae. BmEcR-B transcription and translation level was down regulated by injecting miR-281 mimics. On the other hand, BmEcR-B was up regulated after injection of a miR-281 inhibitor. miR-281 was suppressed by 20E injection but not affected by JH treatments. By these findings, we concluded that miR-281 regulates the BmEcR-B isoforms, but not the BmEcR-A isoform in vivo.