Fei Songa, Yong Huanga,c, Xin Wanga, Shunming Tanga, Xingjia Shena,b#

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aJiangsu University of Science and Technology, Zhenjiang Jiangsu 212018, China;
bThe Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang Jiangsu 212018, China;
cAnimal Science and Technology College, He Nan University of Science and Technology, Luoyang City, 471003, Henan Province, PR China

Received June 25, 2012; in final form July 10, 2012

Abstract: MicroRNAs (miRNAs) are a class of non-protein coding small RNAs of 18-24 nucleotides in length that regulate expression of genes at post-transcriptional levels and play multiple roles in biological processes. Bm-ase plays an important role in the course of nerve development of the silkworm, Bombyx mori. Bmo-miR-9a is a conservative miRNA. By using target prediction software RNA22 and RNAhybrid, we found a target site of Bmo-miR-9a in the 3’UTR of Bm-ase gene. To verify the regulation function of Bmo-miR-9a on the expression of Bm-ase gene, a Bmo-miR-9a over-expressing vector and Bm-ase 3’UTR fused firefly luciferase gene reporter plasmid were constructed, respectively. Then they were used to co-transfect the BmN cells. The result showed that luciferase activity in the co-transfected cells was suppressed compared with the control. A similar result was obtained when BmN cells were co-transfected with artificial synthetic Bmo-miR-9a mimics and Bm-ase 3’UTR fused luciferase reporter plasmid. These results suggest that Bmo-miR-9a can down regulate the expression of Bm-ase gene.

Keywords: Bombyx mori; MicroRNA; Bmo-miR-9a; Bm-ase; Post-transcriptional regulation