Expression of the green fluorescent protein and the hepatitis c virus core protein in the human hepatoma cell line HepG2 using Semliki Forest Virus expression system

Abstract

A SFV replicon vector encoding the enhanced green fluorescent protein (GFP) was used to determine the kinetics of expression of the reporter gene GFP in the liver cell line HepG2.In vitro transcription of the pSFV1-GFP and pSFV-helper plasmids was performed using a commercial kit. Transduction of HepG2 cells with recombinant viral particles (rSFV1-GFP) was performed. Expression of GFP was detected by flow cytometry in rSFV-transduced HepG2 cells. The protein was expressed to high levels with maximum expression 48 hours post transfection (h. p. t.) and was detected up to 96 h. p.t. There was a low cytopathic effect in HepG2 cells at 72 h. p. t. Confirmation of expression of the reporter protein inHepG2 cells using the SFV expression system justified pursuing assays with the Hepatitis C virus (HCV)  Core protein.Viral protein expression was demonstrated in rSFV1- Core-transduced HepG2 cells between 24 and 96 h. p. t., although to lower levels than the reporter protein. A marked cytopathic effect was observed 24 h. p. t. These results indicate that theSFV-based expression system can be a useful tool for transient heterologous protein expression such as the HCV Core in hepatic cell lines, therefore establishing a model for studying HCV pathogenesis.