Fig 1.

The effect of the HA epitope tag at the N terminus of p7 on infectious HCV production and p7-NS2 processing. (A) Organization of the gt1a/gt2a HCV chimera HJ3-5 modified to encode the HA epitope tag at the N terminus of p7 with or without the insertion of a stop codon followed by the EMCV IRES at the junction site of p7 and NS2. The location of p7(KRAA) mutations is also indicated. The gt1a-based sequence is shaded. C, core protein. (B) Intracellular and extracellular virus titers expressed as infectious focus-forming units (FFU) (see Materials and Methods). The dotted line indicates infectious virus detection limit. Mean titers ± standard deviations from four different experiments are shown. (C) The expression of NS2, NS3, ^HAp7, and ^HAp7-NS2 determined by Western blot analysis by using anti-NS2 (α-NS2), anti-NS3 (α-NS3), and anti-HA (α-HA) antibodies, at day 2 postelectroporation of the indicated HCV RNAs.