Figure 3. Representative laser scanning microscopy images of HeLa cells co-transfected with the negative controls, untagged GFP and RFP. The pair of constructs was co-transfected into HeLa cells. After culture, laser scanning microscopy (LSM) images were taken. The low efficiency shown arises from experimental background. The increase of GFP fluorescence intensity is converted to pseudocolor (right panel) that displays variations of pixel gray scales with color.