Novel hepatitis C virus proteins

The hepatitis C virus (HCV) is a major etiological agent of chronic liver diseases. More than 170 million people worldwide are chronically infected, and more than 100 thousand of them develop hepatocellular carcinoma a year. HCV is an enveloped, positive-sense single-stranded RNA virus (+ssRNA virus) of the family Flaviviridae. Its genome is translated to produce a single polyprotein precursor that is further processed by cellular and viral proteases to form 10 viral proteins. Moreover, there is another protein encoded in an alternative reading frame. Two alternative translation mechanisms have been proposed for expression of this alternative reading frame protein (ARFP): a frameshift mechanism and translation initiating from internal start codons. Despite ten years of research its role in vivo is not yet explained. It appears that secondary structures in the core encoding region of HCV genome but not ARFP expression are required for robust viral translation and replication. The results of recent studies suggest that mutations distorting these structures may result not only in slowing down the viral cycle but also in a brand new and utterly unusual serological profile in patients as well as an increased level of expression of ARFP