The Effect of Various Domains of HCV 5’UTR on the Promoter Activity

Based on a previous study, a pGL3-5’UTR plasmid was constructed by substitution of the SV40 promoter with HCV 5’UTR cDNA. A set of deletion mutant plamids: pGL3-5’UTR1 comprising the full sequence of 5’UTR; pGL3-5’UTR2 containing domains II, III and IV; pGL3-5’UTR3 containing domains I, II and III; pGl3-5’UTR4 with domains III and IV; pGl3-5’UTR5 with domains I and II were constructed. HepG2 cells were transfected with the above plasmids. The plasmid carrying the full-length of 5’UTR was transfected into hepG2, Hela, HEK293 and Hela cells. The luciferase mRNA and the enzymatic activity were then detected. The relative luciferase activity associated with the pGL3-5’UTR1, pGL3-5’UTR2, pGL3-5’UTR3, pGL3-5’UTR4 and pGL3-5’UTR5 were 5.91±0.65, 9.52±0.32, 2.72±0.45, 2.64±0.25 and.32±0.09, respectively. The luciferase activity was evident in all four cell lines. The data suggested that the DNA sequence of stem-loop III was the core structure and the domain I, II and IV had a regulating effect. It also showed that cells originated from various tissues could provide efficient accessory factors for HCV 5’UTR sequence than strictly act as a promoter and that the original cells may be the most suitable.