Abstract: This invention relates generally to cells and cell lines that are permissive for hepatitis C virus (HCV) replication, and methods and materials for making and using them.

Abstract: HCV variants are described. The variants include polynucleotides comprising non-naturally occurring HCV sequences and HCV variants that have a transfection efficiency and ability to survive subpassage greater than HCV that have wild-type polyprotein coding regions. Expression vectors comprising the above polynucleotides and HCV variants are also described, as are the provision of cells and host cells comprising the expression vectors. Methods for identifying a cell line that is permissive for infection with HCV are also provided, as are methods for identifying HCV variant polynucleotides with increased transfection efficiencies. Additionally, methods for identifying one or more HCV sequence mutations that provide drug-resistant HCV variants are disclosed.