Establishment of infectious HCV virion-producing cells with newly designed full-genome replicon RNA

Hepatitis C virus (HCV) replicon systems enable in-depth analysis of the life cycle of HCV. However, the previously reported full-genome replicon system is unable to produce authentic virions. On the basis of these results, we constructed newly designed full-genomic replicon RNA, which is composed of the intact 5′-terminal-half RNA extending to the NS2 region flanked by an extra selection marker gene. Huh-7 cells harboring this full-genomic RNA proliferated well under G418 selection and secreted virion-like particles into the supernatant. These particles, which were round and 50 nm in diameter when analyzed by electron microscopy, had a buoyant density of 1.08 g/mL that shifted to 1.19 g/mL after NP-40 treatment; these figures match the putative densities of intact virions and nucleocapsids without envelope. The particles also showed infectivity in a colony-forming assay. This system may offer another option for investigating the life cycle of HCV.