Hepatitis C virus intragenomic interactions are modulated by the SLVI RNA structure of the core coding sequence.

Several RNA interactions are thought to play a role in the regulation of the hepatitis C virus (HCV) life cycle. Most of these interactions involve the 5BSL3.2 domain and therefore occur at the 3' end of the viral genomic RNA. A long-range interaction has also been described between 5BSL3.2 and the 5' untranslated region (UTR). Another interaction involves the SLVI stem loop of the core coding region and the 5'UTR. We aimed to analyse the role of this SLVI domain, which likely interferes with others interactions. By evaluating RNA stability, translation and RNA synthesis, we showed that the SLVI stem loop extensively modulates the effect of the interactions mediated by the 5BSL3.2 domain and strongly affects the IIId/5BSL3.2 interaction. Numerous interactions in HCV genomic RNA have been described in the UTRs and the coding sequence but their roles are poorly understood. We showed that the SLVI domain located in the core coding sequence plays an important role in the translation of the polyprotein, but also in the modulation of long-range RNA interactions centred on the 5BSL3.2 domain. The SLVI domain has been absent from most studies, especially from the extensively used subgenomic replicon; our data highlight the importance of this domain in the studies of these long-range interactions in the HCV life cycle.