Expression dynamics of SGIV VP19. (A) SDS-PAGE analysis of purified recombinant SGIV VP19. Lines M, 1, 2, 3, 4 and 5 showed protein markers, pET-VP19 (uninduced), pET-VP19 (IPTG induced), supernatant, pellet of induced pET-VP19 and the purified pET-VP19, respectively. (B) The specificity of anti-VP19 serum. SGIV or mock infected cells at 48 h p.i. were collected and centrifuged for SDS-PAGE and western blotting. Line M, 1 and 2 showed protein markers, mock and SGIV infected cells at 48 h p.i., respectively. (C) The expression pattern of VP19 during SGIV infection. Actin was chosen as the internal control. (D) VP19 was identified as a late protein. Cells were infected with SGIV at MOI of 0.5 for 6 h and 24 h under the treatment with CHX or AraC, respectively. Then cells were collected for western blotting analysis. The late protein MCP was chosen as a positive control.