Fig. 1.

(A) The partial genome organization of PRRSV. Genomic locations of GP2 and E genes and the E gene-knockout are illustrated. (B) Absence of infectivity of the E gene-knockout full-length clone for PRRSV, P129-ΔE. Marc-145 cells were transfected with the full-length cDNA genomic clone of P129-WT or P129-ΔE and incubated for 5 days. PRRSV-specific CPEs were monitored daily and photographed 4 days post-transfection (upper panels). For immunofluorescence, cells were fixed with cold methanol at 2 days post-transfection and incubated with the N-specific MAb SDOW-17 (lower panels) (magnification 20×). (C) Double staining for N (green) and nsp2/3 (red) proteins for P129-WT (upper panels) or P129-ΔE (lower panels). Marc-145 cells transfected with P129-WT or P129-ΔE plasmid DNA were fixed at 2 days post-transfection and co-stained with nsp2/3-specific rabbit antiserum and N-specific MAb SDOW17. Yellow indicates merged images where both N and nsp2/3 are co-localized.