Viral evolution and interferon resistance of hepatitis C virus RNA replication in a cell culture model.
Hepatitis C virus (HCV) replicates through an error-prone process that may support the evolution of genetic variants resistant to the host cell antiviral response and interferon (IFN)-based therapy. We evaluated HCV-IFN interactions within a long-term culture system of Huh7 cell lines harboring different variants of an HCV type 1b subgenomic RNA replicon that differed at only two sites within the NS5A-encoding region. A replicon with a K insertion at HCV codon 2040 replicated efficiently and exhibited sequence stability in the absence of host antiviral pressure. In contrast, a replicon with an L2198S point mutation replicated poorly and triggered a cellular response characterized by IFN-beta production and low-level IFN-stimulated gene (ISG) expression. When maintained in long term-culture, the L2198S RNA evolved into a stable high-passage (HP) variant with six additional point mutations throughout the HCV protein-encoding region that enhanced viral replication. The HP RNA transduced Huh7 cells with more than 1,000-fold greater efficiency than its L2198S progenitor or the K2040 sequence. Replication of the HP RNA resisted suppression by IFN-alpha treatment and was associated with virus-directed reduction in host cell expression of ISG56, an antagonist of HCV RNA translation. Accordingly, the HP RNA was retained within polyribosome complexes in vivo that were refractory to IFN-induced disassembly. These results identify ISG56 as a translational control effector of the host response to HCV and provide direct evidence to link this response to viral sequence evolution, ISG regulation, and selection of the IFN-resistant viral phenotype.
Sumpter
Rhea
R
Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75235-9048, USA.
Wang
Chunfu
C
Foy
Eileen
E
Loo
Yueh-Ming
YM
Gale
Michael
M
D005075:Biological Evolution; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000502:physiology; D024882:Drug Resistance, Viral; D015967:Gene Expression Regulation, Viral; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D006801:Humans; D050838:Interferon Regulatory Factor-3; D016899:Interferon-beta / Q000096:biosynthesis; D007372:Interferons / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000502:physiology; D012367:RNA, Viral / Q000096:biosynthesis* / Q000737:chemistry; D011956:Receptors, Cell Surface / Q000502:physiology; D012270:Ribosomes / Q000378:metabolism; D051193:Toll-Like Receptors; D014157:Transcription Factors / Q000502:physiology; D017361:Viral Nonstructural Proteins / Q000502:physiology; D014779:Virus Replication; D012324:RNA-Dependent RNA Polymerase
D004268:DNA-Binding Proteins; D050838:Interferon Regulatory Factor-3; D016899:Interferon-beta; D007372:Interferons; D008562:Membrane Glycoproteins; D012367:RNA, Viral; D011956:Receptors, Cell Surface; D051193:Toll-Like Receptors; D014157:Transcription Factors; D017361:Viral Nonstructural Proteins; C494232:IRF3 protein, human; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase