Objective      To investigate the interaction between hepatitis C virus (HCV) core protein and Dicer enzyme and determine the effect of the core protein on Dicer.       Methods      An eukaryotic recombinant plasmid encoding HCV core protein was constructed

and the expression of the protein in the HepG2 cells after transfection was confirmed by immunofluorescence staining and Western blot analysis. The interaction between HCV core protein and Dicer enzyme in the HepG2 cells was detected by co-immunoprecipitation. After dsRNA was synthesized in vitro

inhibitory test was used to determine the effect of core protein on the dicing function of recombinant Dicer e

nzyme to dsRNA.       Results      HCV core protein significantly rescued the expression of extrinsic luciferase gene that was silenced by shRNA compared with control (

P

0.05)

but had no antagonistic effect on siRNA-induced RNAi in vitro. In HepG2 cells

core protein had no significant effect on the expression of Dicer

and a combination of them was also detected. In vitro inhibitory test demonstrated that recombinant Dicer sufficiently cut dsRNA into siRNAs. However

the addition of core protein inhibited the cutting of dsRNA and the production of siRNAs.       Conclusion      Core protein combines with Dicer

and inhibits the dicing function of Dicer for dsRNA to suppress RNA interference.