English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Hepatitis C virus (HCV), the global leading cause of chronic liver disease, has a positive-sense, ssRNA genome that encodes a large polyprotein. HCV polyprotein translation is initiated by an internal ribosome-entry site (IRES) located at the 5' end of the viral genome, in a cap-independent manner, but the regulatory mechanism of this process remains poorly understood. In this study, we characterized the effect of HCV nonstructural proteins on HCV IRES-directed translation in both HCV replicon cells and transiently transfected human liver cells expressing HCV nonstructural proteins. Using bicistronic reporter gene constructs carrying either HCV or other viral IRES sequences, we found that the HCV IRES-mediated translation was specifically upregulated in HCV replicon cells. This enhancement of HCV IRES-mediated translation by the replicon cells was inhibited by treatment with either type I interferon or ribavirin, drugs that perturb HCV genome replication, suggesting that the enhancement is probably due to HCV-encoded protein function(s). Reduced phosphorylation levels of both eIF2alpha and eIF4E were observed in the replicon cells, which is consistent with our previous findings and indicates that the NS5A nonstructural protein may be involved in the regulatory mechanism(s). Indeed, transient expression of NS5A or NS4B in human liver cells stimulated HCV IRES activity. Interestingly, mutation in the ISDR of NS5A perturbed this stimulation of HCV IRES activity. All these results suggest, for the first time, that HCV nonstructural proteins preferentially stimulate the viral cap-independent, IRES-mediated translation.

The regulation of hepatitis C virus (HCV) internal ribosome-entry site-mediated translation by HCV replicons and nonstructural proteins