Replication kinetics of chimeric HEV luciferase replicons with swapped HVRs. (A) Replication kinetics of the wild-type genotype 1 HEV replicon pSK-REP, the chimeric replicon pSKHEV2-Sw-luc, and the mutant replicon pSKHEV2-ΔHVR-luc. The firefly luciferase activity in cell lysates of Huh7 cells was determined at 1, 2, 3, and 4 days posttransfection. Data were normalized for transfection efficiency among the chimeric replicons as determined by measurement of the Renilla luciferase activity. The value determined with the parental HEV replicon (pSK-REP) was set as 100% and used as a reference to normalize the replication of other mutant replicons. A replicon (pSK-GAA) carrying an inactivating mutation (GAA) in RdRp served as a negative control. (B) Replication of the genotype 3 wild-type HEV replicon pSHEV3-luc and the chimeric replicon pSHEV3-Hu-luc in Huh7 cells. The Renilla luciferase activity was determined at daily intervals for 4 days posttransfection. The luciferase value determined for the parental wild-type HEV replicon pSHEV3-luc was set as 100% and used to normalize the replication of pSHEV3-Hu-luc, while the pSK-GAA replicon served as a negative control. Values are means and standard deviations for at least two independent experiments, each performed in quadruplicate. Asterisks (*) indicate statistical differences compared to the parental wild-type HEV replicons. RLU, relative light units.