Fig. 8. Subconfluent MDCK cells expressing F_c38-63 were transfected with a vector expressing the caveolin 1 siRNA. This vector also expressed EGFP under the control of a separate promoter. Forty-eight hours post-transfection, the cells were fixed (A-C) or incubated with anti-F_c receptor antibodies for 30 minutes at 4°C, washed and then fixed (D-F). Following permeabilization, the cells in A-C were incubated with caveolin 1 antibodies (A) followed by anti-rabbit IgG conjugated to Alexa Fluor-594. The cells in D-F were directly incubated with anti-rat IgG conjugated to Alexa Fluor-594. Following washing, cells were analyzed by confocal microscopy. Arrows in A and B mark the border of the cell expressing the caveolin 1 siRNA. Note the absence of caveolin staining in the plasma membrane. The bar graph in G has quantified the average effect of the caveolin 1 siRNA on the caveolin 1 protein level and F_c38-63 surface expression in 20 randomly chosen cells from two independent experiments. Bars, 10 µm.