Expression of hepatitis C virus structural proteins in Saccharomyces cerevisiae

Expression in yeast may prove more amenable to generating large amounts of viral antigens for a vaccine candidate. We, therefore, cloned the gene encoding the Hepatitis C virus (HCV) structural proteins (C-E1-E2, c740) fused in-frame with, and immediately 3' to, the chickenlysozyme signal peptide (C-SIG) gene and under the control of the yeast glyceraldehyde-3-phosphate dehydrogenase gene promoter. In yeast, the HCV structural proteins were expressed in two different forms: a processed and a nonprocessed aggregated form. Biophysical characterization by sucrose linear gradient centrifugation revealed that both forms were present in the same fractions with a buoyant density of 1.127-1.176 g/cm(3). These findings suggest that the efficient synthesis of HCV structural proteins in yeast may be an important tool to study virus assembly and may lead to the development of an HCV vaccine.