%0 Journal Article %A Roussel, Juliette %A Pillez, André %A Montpellier, Claire %A Duverlie, Gilles %A Cahour, Annie %A Dubuisson, Jean %A Wychowski, Czeslaw %T Characterization of the expression of the hepatitis C virus F protein %D 2003 %J Journal of General Virology, %V 84 %N 7 %P 1751-1759 %@ 1465-2099 %R https://doi.org/10.1099/vir.0.19065-0 %I Microbiology Society, %X Hepatitis C virus (HCV) is an important human pathogen that affects 170 million people worldwide. The HCV genome is approximately 9·6 kb in length and encodes a polyprotein that is proteolytically cleaved to generate at least 10 mature viral protein products. Recently, a new protein, named F, has been described to be expressed through a ribosomal frameshift within the capsid-encoding sequence, a mechanism unique among members of the family Flaviviridae. Here, expression of the F protein was investigated in an in vitro transcription/translation assay. Its expression in mammalian cells was confirmed using specific recombinant vaccinia viruses; under these conditions, protein expression is dependent on the HCV IRES. The F protein was tagged with firefly luciferase or the Myc epitope to facilitate its identification. Ribosomal frameshifting was dependent on the presence of mutations in the capsid-encoding sequence. No frameshifting was detected in the absence of any mutation. Furthermore, analysis of the F protein in time-course experiments revealed that the protein is very unstable and that its production can be stabilized by the proteasome inhibitor MG132. Finally, indirect immunofluorescence studies have localized the F protein in the cytoplasm, with notable perinuclear detection. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.19065-0