Fig. 8.
ISG20 inhibits HAV replication. (A) Schematic representation of the HAV-Luc replicon (Yi et al., 2002). (B) Replication kinetics of HAV-luc replicon in 7.5-Bsr, 7.5-ISG20 and 7.5-ISG20m cells. Data shown are representative of 3 independent experiments. (C and D) HEK293-FLP-IN T-Rex cells that conditionally express ISG20 or ISG20m were cultured in the presence or absence of 2 μg/ml tetracycline for 3 days, to induce or repress ISG20/ISG20m expression, respectively, and subsequently infected with HM175/18f virus (MOI = 1) for 5 days. Then cell lysates were harvested and immunoblotted for expression of ISG20/ISG20m (using anti-Flag antibody) and GAPDH (panel C), and HAV infectious virus yield was determined by infrared fluorescent immunofocus assay of 10-fold serially diluted samples on FRhK-4 cells (panel D). In panel D, the control dish in ISG20m (+ tet) at 106 dilution was stained with secondary antibody conjugate only.