Western-blot analysis to monitor for vacuolar delivery. Tobacco mesophyll protoplasts were transfected with 10, 30 or 100 μg plasmid DNA encoding for each marker/reporter as indicated below or mock-transfected. Gel blot analysis using GFP (A) or RFP antibodies (B) reveals signals corresponding to the calculated molecular weight of the expressed proteins. Signals which might correspond to reporters with proteolytically cleavaged ubiquitin moiety are indicated by asterisks. Arrowheads indicate the size of the vacuolar GFP core and vacuolar RFP.