Immunoblot analysis of HAV polyproteins expressed from cDNA in the presence of HAV 3C in BS-C-1 cells. Transient transfection was performed in the presence of recombinant vaccinia virus vTF7-3, which carries the gene for T7 RNA polymerase. Proteins P1-2380, P1-2993, and P1P2 were expressed from plasmids pEHP1-2380, pEHP1-2993, and pEHP1P2, respectively, in the absence (A and C, lanes 3, 5, and 7) or presence (A and C, lanes 4, 6, and 8) of HAV 3C expressed from pE5H-P3. VP1-specific products were detected with HAV VP1 antiserum (A), and VP4-specific products were detected with HAV VP4 antiserum (C). (B) VP1-immunoreactive proteins P1-3107 and P1-3216 expressed from plasmids pEHP1-3107 and pEHP1-3216, respectively, in the absence (lanes 3 and 5) or presence (lanes 4 and 6) of HAV 3C expressed from pE5H-P3. Extract from mock-transfected BS-C-1 cells as a negative control (NC) and extract from HAV-infected cells as a positive control (HAV) were analyzed on the same gel (all panels). Immunoreactive proteins VP1 (A and B), PX (A), and VP0VP3 and VP0 (C) are indicated to the right; molecular masses of marker proteins are indicated in kilodaltons to the left (all panels).