The present invention relates to the production of structural proteins and virus-like particles (VLPs) of flaviviruses and hepatitis C. Production is through use of a single expression cassette comprising a viral structural gene, a furin encoding gene and a bicistronic expression element such as an internal ribosome entry site (IRES) between the viral and furin genes. Both the viral gene and furin gene can include a partial capsid encoding sequence acting as a signal peptide to co-locate the viral protein and furin and to act as a membrane anchor for the viral protein and furin. A separate expression cassette comprising a non-structural viral gene can be combined with the initial cassette. The structural proteins and VLPs can be used in vaccines and in the treatment of viral infections.
