【目的】研究gp64基因相对应的多个dsRNA对家蚕核型多角体病毒增殖的抑制效果。【方法】体外合成dsRNA，通过病毒滴度试验、实时定量RT-PCR法研究gp64基因的不同区域、不同长度与RNAi干扰效果的关系。【结果】供试的6个dsRNA的最大抑制效果相当（滴度TCID50的最大抑制差值为4.00左右）；经RNAi的不同时间点的gp64 mRNA 表达水平均明显下调(P<0.01)，其中48 h的gp64 mRNA的表达量约为对照的1/300。【结论】6个dsRNA均能有效地抑制病毒的基因表达和增殖；gp64 ORF第1 390～1 499位点（G3-3）是RNAi的较佳靶位点。

【Objective】To investigate the inhibitory effects of the different corresponding dsRNAs of gene gp64 on the replication and multiplication of Bombyx mori nuclear polyhedrosis virus(BmNPV).【Method】DsRNA are synthesized in vitro .Using the methods of measuring virus titer and real-time fluorescent quantitative RT-PCR, we test the interference effect of the different target domain, or length of gp64 gene.【Result】The maximum inhibitory effect of the three dsRNAs fragments (about 400bp) show no obvious difference (the maximum distinction of virus titer TCID50 is about 3.50).The inhibitory effect of dsRNA with about 100bp length is equal to those of with about 400bp length. At different period of RNA interference, the expression level of gp64 mRNA are downregulated (P<0.01). At 48 hpt, the expression amount of gp64 mRNA is about 1/300 of the control .【Conclusion】The six dsRNAs studied can inhibit the expression of viral gene and the multiplication of BmNPV. The best target site of RNAi is located at 1390~1499 in gp64 ORF.