[Optimization of RNA interference strategy for lef-11 gene of Bombyx mori nucleopolyhedrovirus].

Objective: Gene lef-11 is one of the high conservative late expression factors in Bombyx mori nucleopolyhedrovirus (BmNPV), and contributes to virus replication and proliferation. The effective RNA interference will increase the resistance of host cells to BmNPV.
Methods: Choosing two classical skeleton sh-RNA-loop and miRNA skeleton based on silkworm endogenous, we constructed targeted-lef-11 interference vectors: pIZ-shRNA1, pIZ-shRNA2 and pIZ-DsRed-amiR279 and optimized these vectors via different promoters.
Results: First, comparing the interference efficiency of shRNA-based and miRNA-based RNAi vectors on the same site, we found the interference efficiency of pIZ-DsRed-amiR279 on target gene was more than 90%, better than that of RNAi shRNA-based and could be applied for follow-up experiments. Second, we evaluated the antiviral effect of different interference vectors driven by A4, IE1, IE1-295, IE2, IE2-339, hr3A4 and hsp70 promoters and found that the most active promoter had less interference effect on the target gene and IE1 was the optimal screening seven promoters, which demonstrated that the accumulation of pre-miRNA was not contribute to interference.
Conclusion: The results showed that the interference effect on the target gene depended on kinds of factors, such as the interference skeleton, the activity of promoter and the function of target gene.