RESUMEN
Hepatitis C virus (HCV) genotype 3a is widespread worldwide, but no replication system exists for its study. We describe a subgenomic replicon system for HCV genotype 3a. We determined the consensus sequence of an HCV genome isolated from a patient, and constructed a subgenomic replicon using this clone. The replicon was transfected into HuH-7 cells and RNA replication was confirmed. We identified cell culture-adaptive mutations that increased colony formation multiple-fold. We have therefore established a genotype 3a replicon system that can be used to study this HCV genotype.
Asunto(s)
Hepacivirus/genética , Hepacivirus/fisiología , ARN Viral/metabolismo , Replicón/genética , Replicación Viral/genética , Adaptación Fisiológica/genética , Línea Celular Tumoral , Ensayo de Unidades Formadoras de Colonias , Humanos , Mutación , FenotipoRESUMEN
Hepatitis C virus (HCV) exists in infected individuals as quasispecies, usually consisting of a dominant viral isolate and a variable mixture of related, yet genetically distinct, variants. A prior HCV infection system was developed using human hepatocellular carcinoma cells cultured in the three-dimensional radial-flow bioreactor (RFB), in which the cells retain morphological appearance and their differentiated hepatocyte functions for an extended period of time. This report studies the selection and alteration of the viral quasispecies in the RFB system inoculated with pooled serum derived from HCV carriers. Monitoring the viral RNA and core protein in the culture supernatants, together with nucleotide sequencing of hypervariable region 1 of the HCV genome, demonstrated that (1) the virus production intermittently fluctuated in the cultures, (2) the viral genetic diversity was markedly reduced 3 days post-infection (p.i.), and (3) dominant species changed on days 19-33p.i., suggesting that the virus populations can be selected according to susceptibility to the viral infection and replication. A therapeutic effect of interferon-alpha also demonstrated the inhibition of HCV expression. Thus, this HCV infection model in the RFB system should be useful for investigating the dynamic behavior of HCV quasispecies in cultured cells and evaluating anti-HCV compounds.
Asunto(s)
Reactores Biológicos/virología , Hepacivirus/crecimiento & desarrollo , Cultivo de Virus/métodos , Secuencia de Aminoácidos , Sustitución de Aminoácidos/genética , Línea Celular Tumoral , Variación Genética , Hepacivirus/genética , Humanos , ARN Viral/genética , Selección Genética , Alineación de Secuencia , Análisis de Secuencia de ADN , Proteínas del Núcleo Viral/genéticaRESUMEN
Hepatitis C virus (HCV) infection represents a major public health problem throughout the world. The establishment of viral replicons has enhanced our understanding of the mechanism underlying HCV replication. However, the specific virus-host cell interactions involved in HCV RNA replication are not well understood. In the present study, we isolated several human hepatoma Huh-7-derived subclones with a range of HCV RNA replication efficiencies by end-point dilution. Of these, the clones HuhTe4 and HuhTe6 were observed to proliferate at the same rate; however, HuhTe6 supported a significantly greater degree of viral RNA replication. Using cDNA microarray analysis, a total of 36 genes (0.4%) demonstrated variable expression, with a >or=2-fold difference in expression noted between HuhTe4 and HuhTe6. Among genes that are implicated in a variety of functional categories, a subset of these differentially-expressed genes has a role in signal transduction and cell communication, including thioredoxin-interacting protein, Rab6B, sorting nexin 16 and UDP-galactose:ceramide glycosyltransferase. The genes identified in this study should be examined further to determine their roles in HCV RNA replication. The Huh-7 subclones identified in this study provide a tool for identifying novel host factors involved in viral replication.