title: Hepatitis C virus nonstructural proteins are localized in a modified endoplasmic reticulum of cells expressing viral subgenomic replicons.
abstract: For many years our knowledge on hepatitis C virus (HCV) replication has been based on in vitro experiments or transfection studies. Recently, the first reliable system for studying viral replication in tissue culture cells was developed. Taking advantage of this system, we examined in detail the localization of viral nonstructural (NS) proteins in cells containing functional replication complexes. By fractionation experiments and immunomicroscopy, we observed that all NS proteins were associated with the endoplasmic reticulum (ER) membranes, confirming the hypothesis that the ER is the site of membrane-associated HCV RNA replication. Interestingly, NS3 and NS4A were preferentially localized in endoplasmic reticulum cisternae surrounding mitochondria, suggesting additional subcellular compartment-related functions for these viral proteins. Furthermore, the immunoelectron microscopy revealed the loss of the organization and other morphological alterations of the ER (convoluted cisternae and paracrystalline structures), resembling alterations observed in liver biopsies of HCV-infected individuals and in flavivirus-infected cells.
authors.affiliation: Dipartimento di Biochemie e Biotecnologie, Università de Napoli Federico II, Naples, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Mottola
authors.forename: Giorgia
authors.initials: G
authors.lastname: Cardinali
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ceccacci
authors.forename: Caterina
authors.initials: C
authors.lastname: Trozzi
authors.forename: Linda
authors.initials: L
authors.lastname: Bartholomew
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Torrisi
authors.forename: Emanuela
authors.initials: E
authors.lastname: Pedrazzini
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonatti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Migliaccio
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002462:Cell Membrane / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000737:chemistry*; D005455:Fluorescent Antibody Technique; D016174:Hepacivirus / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D016253:Microscopy, Immunoelectron; D012093:Replicon; D017361:Viral Nonstructural Proteins / Q000032:analysis*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; D012324:RNA-Dependent RNA Polymerase
chemical_list: D002118:Calcium; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C093542:NS4 protein, hepatitis C virus; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase