Interferon-Stimulated Gene 15 Conjugation Stimulates Hepatitis B Virus Production Independent of Type I Interferon Signaling Pathway In Vitro

Figure 1

ISG15 expression and ISGylation were increased by transfection. HepG2.2.15 cells were transfected with the ISG15 expression plasmid or GFP-expressing plasmid. (a) Levels of ISG15 mRNA were determined by real-time PCR (normalized by GAPDH) 24 hours after transfection. PEI, transfection regent polyethyleneimine (PEI) treatment only; GFP, transfected with 4 μg GFP-expressing plasmid; ISG15, transfected with 4 μg ISG15 plasmid. The results are presented as the means ± SD, ; error bars indicate SD. . (b) Protein ISGylation was further assessed by western blot with or without ISG15 overexpression. Molecular mass markers are shown on the left (kDa).

(a)

(b)