Ultrastructural and quantitative analysis of the lipid droplet clustering induced by hepatitis C virus core protein
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Hepatitis C virus (HCV) release is linked to the formation of lipid droplet (LD) clusters in the perinuclear area of infected cells, induced by the core protein. We used electron microscopy (EM) to monitor and compare the number and size of LD in cells producing the mature and immature forms of the HCV core protein, and 3D EM to reconstruct whole cells producing the mature core protein. Only the mature protein coated the LD and induced their clustering and emergence from endoplasmic reticulum membranes enriched in this protein. We found no particular association between LD clusters and the centrosome in reconstructed cells. The LD clustering induced by the mature core protein was associated with an increase in LD synthesis potentially due, at least in part, to the ability of this protein to coat the LD. These observations provide useful information for further studies of the mechanisms involved in HCV-induced steatosis.
KeywordsHCV Lipid droplet Steatosis Electron microscopy 3D reconstruction
Hepatitis C virus
Signal peptide peptidase
Semliki forest virus
This work was supported by a grant INSERM-DHOS « Virosteatose ». M.D. was supported by a fellowship from the INSERM and Région Centre. We thank Dr Mario Mondelli (Istituto di Clinica delle Malattie Infettive, Pavia, Italy) for providing us with the monoclonal B12F8 anti-HCV core reagent. We thank Sylvie Trassard and Fabienne Arcanger for technical assistance. We thank Bruno Giraudeau, Eric Piver and Pierre Besson for helpful discussions and feedback on this work. Our data were obtained with the assistance of the RIO Electron Microscopy Facility of François Rabelais University.
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