FIG 1.

The M21T mutant promoted HCV virus production. (A) Schematic representation of JFH1-WT and JFH1-M21T mutant in helix α₀ of NS3 protein. Amino acids 1 to 632 are numbered according to the numbering used for NS3 protein. Amino acids 1040 and 1050, indicated in the parentheses, are numbered according to the HCV polyprotein. The point mutation at position 21 is indicated by an asterisk. The M21 side chain is presented as blue sticks in the model of helix α₀. (B to D) Huh7.5.1 cells were electroporated with in vitro-transcribed JFH1 RNA of the WT, M21T mutant, or GND mutant. The cells at day 2 postelectroporation were analyzed by immunofluorescence for HCV E2 and nuclei (red and blue channels, respectively) (B) and intracellular HCV RNA levels (C), and the supernatant infectivity titers were determined at different time points after electroporation (D). Error bars indicate standard deviations calculated from 3 independent experiments. ns, not significant.