Remarkable advances have been made through recent demonstrations of hepatitis C virus (HCV) replication in cultured cells transfected with in vitro synthesized viral genome RNA. From the HCV JFH1 (genotype 2a) subcultured successively in Huh-7 cells we have identified several missense mutations near the junction of NS5A and NS5B genes. Reverse genetic analysis indicated that two mutations in the N-terminal region of NS5B replicase caused delayed viral RNA replication and protein expression in the early stage of infection. However, the mutant viruses showed significantly alleviated effects on cell growth inhibition, proteolysis of viral proteins, apoptotic DNA cleavage, and induction of antiviral responses, giving rise to a 100-fold higher titer compared to the parental JFH1 virus in a more extended time period. These results suggested that delayed replication and reduced cytotoxicity can be characteristic features of cell culture-adaptive mutants with enhanced infectivity.
Bibliographical noteFunding Information:
This work was supported by the 21C Frontier Grant for Functional Human Genome Research (M103KB010020-06K0201-02020) from the Ministry of Science and Technology of Korea. J.P. Kim was supported by the Brain Pool Program (041S-4-8) of the MST of Korea. J. Kang was supported by the BK21 graduate scholarship from the Ministry of Education of Korea.
- Cell culture-adaptive mutation
- HCV JFH1
ASJC Scopus subject areas
- Cancer Research
- Infectious Diseases