Short hairpin RNA expression for enhancing the resistance of <i>Bombyx mori (Bm)</i> to nucleopolyhedrovirus <i>in vitro</i> and <i>in vivo</i>

Abstract

A new paradigm of RNAi technology has been studied for enhancing the resistance to virus in plants and animals. Previous studies have shown that the Bombyx mori (Bm) U6 promoter based shRNA is an effective tool for inducing RNAi in Bombyx mori cell line. However, widespread knockdown and induction of phenotypes in Bm larvae have not been fully demonstrated. In this study, we examined Bm U6 promoter based shRNA expression for suppressing Bm nucleopolyhedrovirus (NPV) in the Bm cell line and silkworm larvae. We measured the relative expression level of replication genes of BmNPV in hemolymph of silkworm larvae and BmN cells transfected with recombinant targeting shRNA by quantitative real time polymerase chain reaction (PCR). These results indicated that the recombinant shRNA expression system was a useful tool for resistance to BmNPV in vivo and in vitro. The approach opens the door of RNAi technology as a wide range of strategies that offer a technically simpler, cheaper, and quicker gene-knockdown by recombinant shRNA for future genetics in silkworm Bm and other related species.

Key words: RNA interference (RNAi), Silkworm Bombyx mori (Bm) cell line, short hairpin RNA (shRNA), Bm nucleopolyhedrovirus (BmNPV), quantitative real time polymerase chain reaction, Bm U6 promoter.