FIG 7.

Detection of FMDV 2A fusion proteins by immunofluorescence staining within cells. BHK cells were untreated or transfected with wt or mutant FMDV RNA transcripts. At 8 h posttransfection, the cells were fixed. FMDV capsid proteins or the FMDV 2A peptide was detected using anti-FMDV O1K polyclonal antibodies (upper panels) or anti-2A antibodies (lower panels), respectively, plus a secondary antibody labeled with Alexa Fluor 568 (red). The 2A substitutions are indicated. Untransfected cells were used as a negative control, whereas the O1K VP1 K210E mutant, described previously (7), in which the 2A remains joined to VP1, served as a positive control. The cellular nuclei were visualized with DAPI (blue). Bars, 50 μm.