Binding of the La autoantigen to the hepatitis C virus 3' untranslated region protects the RNA from rapid degradation in vitro.

We have analysed hepatitis C virus (HCV) RNAs in an in vitro RNA degradation assay. We found that the 3' end of positive polarity HCV RNA is sensitive to cytosolic RNases whereas the 3' end of negative polarity HCV RNA is relatively stable. Interaction of the HCV 3' untranslated region with the cellular La protein prevented premature degradation of the HCV RNA. One may speculate that HCV RNAs interact with La protein in infected cells to prevent premature degradation of the viral RNAs.