Figure 4

Efficiency of F2A cleavage in CherryFP-F2A-GFP context. F2A sequences of various lengths were used to co-express CherryFP and GFP proteins from pCherryFP-F2A-GFP constructs (a, schematic presentation) in vitro using coupled transcription/ translation rabbit reticulocyte lysates (b) and transfected HeLa cells (c). For TnT, reticulocyte lysates were programmed with 20 ng of plasmid DNA and translation products were resolved by the 12% SDS-PAGE. For in vivo studies, HeLa cells were transfected with 1.5 μg of plasmid DNA and harvested 30 h post transfection. Cells were lysed in RIPA buffer and equal amounts of total protein for each transfection were loaded onto 12% SDS-PAGE gel. The proteins were transferred onto a nitrocellulose membrane, blocked in PBST containing 5% milk and probed with anti-GFP (upper blot) and anti-CherryFP (lower blot) antibodies overnight at 4°C. Detection of bound primary antibody was achieved by using respective secondary antibodies, followed by ECL detection. All experiments were done in triplicates.