ABSTRACT
Hepatitis C virus (HCV) is an enveloped, positive-stranded RNA virus that belongs to the Flaviviridae family. The antiviral mechanisms of interferon and ribavirin also target the highly conserved 5'- untranslated region (UTR). The HCV genome contains a large ORF encoding for a 3011 amino acid-long polyprotein, which is proteolytically processed at the endoplasmic reticulum membrane into ten different mature viral proteins by cellular and viral proteases. The 5'-UTR binds to host ribosomes to translate the HCV polyprotein using an internal ribosome entry site (IRES) mechanism. A number of viruses utilize the IRES mechanism for gene expression, which is distinct from capdependent translation of cellular genes. Cloning and sequencing of the HCV genome has increased our understanding of the HCV molecular virology and led to model systems to study viral replication and develop antiviral drugs. HCV infection is initiated by the attachment and entry of virus particles into host cells by receptor-mediated endocytosis.
