Positive and negative effects on translation of the hepatitis C virus 3' untranslated region.

OBJECTIVES

To determine the role of the hepatitis C virus 3' untranslated region in viral mRNA translation in transfected cells and in cell extracts.

STUDY DESIGN/METHODS: Noninfectious hepatitis C virus mini-genome RNAs with various deletions in the viral 3' untranslated region were transfected into cells or translated in vitro, and the translation efficiency was determined.

RESULTS

We have found that the presence of the hepatitis C virus 3' untranslated region modestly increases mRNA translation. The positive effect correlated with the binding of a 45-kDa cytoplasmic factor to the hepatitis C virus 3' untranslated region. Furthermore, the U-rich sequence in the hepatitis C virus 3' untranslated region inhibits translation of capped and polyadenylated mRNAs as a result of the hybridization.

CONCLUSIONS

The modest effect of the hepatitis C virus 3' untranslated region on translation suggests that it does not play a major role in mRNA translation. The inhibitory effect of the hepatitis C virus 3' untranslated region on translation of polyadenylated mRNAs supports the notion that translation of hepatitis C virus mRNAs occurs independently of a polyA tail.