Assembly of functional hepatitis C virus glycoproteins on infectious pseudoparticles occurs intracellularly and requires concomitant incorporation of E1 and E2 glycoproteins.
Hepatitis C virus (HCV) E1 and E2 envelope glycoproteins (GPs) displayed on retroviral cores (HCVpp) are a powerful and highly versatile model system to investigate wild-type HCV entry. To further characterize this model system, the cellular site of HCVpp assembly and the respective roles of the HCV GPs in this process were investigated. By using a combination of biochemical methods with confocal and electron microscopic techniques, it was shown that, in cells producing HCVpp, both E1 and E2 colocalized with retroviral core proteins intracellularly, presumably in multivesicular bodies, but not at the cell surface. When E1 and E2 were expressed individually with retroviral core proteins, only E2 colocalized with and was incorporated on retroviral cores. Conversely, the colocalization of E1 with retroviral core proteins and its efficient incorporation occurred only upon co-expression of E2. Moreover, HCVpp infectivity correlated strictly with the presence of both E1 and E2 on retroviral cores. Altogether, these results confirm that the E1E2 heterodimer constitutes the prebudding form of functional HCV GPs and, more specifically, show that dimerization with E2 is a prerequisite for efficient E1 incorporation onto particles.
Sandrin
Virginie
V
IFR128 BioSciences Lyon-Gerland, Lyon, F-69007 France.|Ecole Normale Supérieure de Lyon, Lyon, F-69007 France.|INSERM, U412, Lyon, F-69007 France.
Boulanger
Pierre
P
Laboratoire de Virologie et Pathogénèse Virale, CNRS UMR-5537, Faculté de Médecine de Lyon and Institut Fédératif de Recherche RTH Laennec, Lyon, France.
Penin
Francois
F
Institut de Biologie et Chimie des Proteines, CNRS-UMR 5086, Université Claude Bernard Lyon 1, Lyon, France.
Granier
Christelle
C
IFR128 BioSciences Lyon-Gerland, Lyon, F-69007 France.|Ecole Normale Supérieure de Lyon, Lyon, F-69007 France.|INSERM, U412, Lyon, F-69007 France.
Cosset
François-Loïc
FL
IFR128 BioSciences Lyon-Gerland, Lyon, F-69007 France.|Ecole Normale Supérieure de Lyon, Lyon, F-69007 France.|INSERM, U412, Lyon, F-69007 France.
Bartosch
Birke
B
IFR128 BioSciences Lyon-Gerland, Lyon, F-69007 France.|Ecole Normale Supérieure de Lyon, Lyon, F-69007 France.|INSERM, U412, Lyon, F-69007 France.
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000737:chemistry; D016174:Hepacivirus / Q000502:physiology*; D006801:Humans; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D014759:Viral Envelope Proteins / Q000378:metabolism*; D019065:Virus Assembly
C087035:E1 protein, Hepatitis C virus; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus