OBJECTIVETo study the mechanism of hepatitis C virus (HCV) gene regulation and the inhibitory effect of antisense RNA on HCV gene expression in vitro.

METHODSThe hepatoblastoma cell line (HepG2) was co-transfected by recombinant plasmid of antisense RNA complementary to HCV 5' untranslated region (5'UTR)and HCV 5' UTR Directed luciferase (luc) gene expression recombinant plasmid. Meanwhile a reversed HCV 5'UTR recombinant plasmid which can not transcribe as antisense RNA in the cell and a recombinant plasmid in which the luc was regulated by simian virus 40 (sv40) 5'UTR were used as controls respectively. The level of luc gene expression was determined by an enzymatic assay.

RESULTSThe antisense RNA which directed to HCV 5'UTRcould obviously knock down the level of luc gene expression and the close-dependent inhibition of antisense RNA was observed at the same time. However the above inhibition was not shown in the cells co-transfected by reversed HCV 5'UTR recombinant plasmid and HCV 5'UTR directed luc gene expression recombinant plasmid. No reduction was observed in luc gene expression level in the cell co-transfected by both antisense RNA recombinant plasmid and SV40 5'UTR directed luc gene expression recombinant plasmid.

CONCLUSIONHCV 5'UTR plays an important role in regulation of viral gene expression. The antisense RNA complementary to HCV 5'UTR could effectively inhibit the gene expression regulated by HCV 5'UTR in vitro.