FIG. 3.

The JSRV Env signal peptide localizes to the cell nucleus. 208F cells were transfected with the expression constructs for HA-tagged JSRV Env, HA-tagged JSRV Env signal peptide, or empty vector control (ΔGPHA [top panels], ΔGPSPHA [middle panels], or pCDNA3.1 [bottom panels], respectively) and grown on chamber slides for 40 h prior to fixation and incubation with an FITC-conjugated polyclonal antibody to HA and a phycocyanin-conjugated monoclonal antibody to nucleophosmin (B23). To visualize the nuclei of all cells, the cells were also stained with DAPI. Immunofluorescence images were recorded at excitation wavelengths of 350 nm (DAPI), 490 nm for FITC (HA), and 620 nm for phycocyanin (B23); individual and merged images are shown. Bar, 5 μm. Magnification, ×630.