Introduction

The Hepatitis C Virus (HCV) is the main causative agent of non-A, non-B hepatitis in humans and a major cause of mortality and morbidity in the world. At this time there is no effective vaccination or cure for Hepatitis C, an infection affecting at least 170 million people worldwide. This slow-processing disease is transmitted through contaminated blood transfusions and needle sharing, and frequently leads to liver cirrhosis and cancer (Cohen, 1999).

The genetic pattern associated with HCV consists of a positive-sense-strand RNA genome of ∼9600 nucleotides (nts) that contains a single large open-reading frame. The structure and organization of the HCV genome is similar to those of members of the pestivirus and flavivirus genera of the family Flaviviridae (Takamizawa et al., 1991). HCV is now classified as a distinct genus of this family, with at least six major genotypes that differ from each other in their nucleotide sequence by up to 35%. The 341-nts long 5′untranslated region (5′UTR) and the adjacent core protein coding sequence are highly conserved (Simmonds, 1995; Smith et al., 1995). The HCV RNA 5′UTR contains a highly structured internal ribosome entry site (IRES) that mediates initiation of translation of the viral polyprotein by a 5′ cap-independent mechanism that is unprecedented in eukaryotes [(Jackson and Kaminski, 1995; Reynolds et al., 1995) (Figure 23.1)]. The first step in translation initiation is the assembly of a 43S preinitiation complex consisting of the eukaryotic initiation factors (eIF) 3, eIF 2, GTP, the initiator tRNA and a 40S ribosomal subunit.