Similar to other positive-strand RNA viruses, the non-coding regions of HCV RNA, referred herein as 5′ and 3′ untranslated regions (5′UTR and 3′UTR), contain important sequence and structural elements critical for HCV translation and RNA replication. The 5′UTR harbors an internal ribosome entry site (IRES) that directs viral protein translation via a cap-independent mechanism. As the initiation sites for RNA synthesis, both 5′UTR and 3′UTR contain signals that are indispensable for and regulate viral RNA replication. Additional structural elements involved in translation or RNA replication are also present in both ends of the protein (core and NS5B)-coding regions. These RNA elements interact with each other either directly or through the binding of viral and cellular proteins that are most likely involved in the regulation of translation and RNA replication processes. Since RNA replication and translation occur on the same RNA molecule, mechanisms must exist to regulate and separate these two processes. This chapter details the current understanding of the roles of the UTRs and other structural components in the viral RNA as well as their binding proteins in HCV translation and RNA replication and speculate on the possible mechanisms regulating these two different processes.
Copyright © 2006, Horizon Bioscience.