FIG. 1.

Cellular distribution of the PRRSV N protein. Marc-145 cells prepared on microscope coverslips were infected with PRRSV (North American PA8 strain) and incubated for 16 h. The cells were fixed with 4% formaldehyde and permeabilized with 0.1% NP-40. The cells were then stained with the N-specific MAb SDOW17, followed by staining with goat anti-mouse antibody conjugated with FITC. (A) The cells were examined by fluorescence microscopy (magnification, ×40). (B) Nucleolar region under higher magnification (×100), showing the accumulation of FITC-MAb within regions of the nucleolus. No-N, nucleolar N; Cy-N, cytoplasmic N.