We will use RNA interference (RNAi) to "knock down" specific genes in order to evaluate their roles on viral replication. Small double-stranded RNA molecules will be used to induce sequence-specific degradation of homologous single-stranded RNA. For most of these studies stock Huh7.5 cells will be compared to Huh7.5 cells stably expressing the full-length Genotype 1a HCV replicon developed in Dr. Charles Rice’s laboratory. The methodology detailed below is routine in our laboratory and the laboratories of our collaborators.