FIG 4.

Transient-expression assays to determine 2A/2B cleavage induced by the wt and mutant FMDV cDNAs. The indicated plasmids were transfected into vTF7-3 infected BHK cells as described in Materials and Methods. After 24 h, cell extracts were prepared and analyzed by SDS-PAGE and immunoblotting using an anti-FLAG antibody. The uncleaved P1-2A-2BC-FLAG and the cleavage product (2BC-FLAG) are marked. Molecular mass markers (kDa) are indicated on the left. The cleavage activities (percentage of cleaved product) of the wt and each 2A mutant were determined by quantifying the intensity of the signal for the FMDV capsid proteins using ImageJ (v1.50) and are indicated above each lane.