Figure 4. Immunocytochemical assays for Robo4 in RF/6A cells and human RPE cells. The fluorescence, representing the expression of Robo4 in both cell lines, was very strong in NS siRNA-treated cells but was barely detectable in the Robo4-siRNA-treated cells. Abbreviations: control siRNA treated cells (NS); Robo4 siRNA-treated RF/6A cells (RF/6A siRNA); Robo4 siRNA-treated RPE cells (RPE siRNA). Bar denote 50 μm.