FIG. 1.

EGFP-VP4 FRAP experiment on the actin cytoskeleton. Cos-7 cells were transiently transfected with a plasmid encoding EGFP-VP4. At 24 h posttransfection, living Cos-7 cells expressing EGFP-VP4 were observed with a confocal microscope. A part of a EGFP-VP4-labeled filament was photobleached by high-power laser excitation (the photobleached region is indicated by a white arrow). EGPF-VP4 fluorescence recovery was observed for 20 min after photobleaching. Shown are projections of 0.3-μm x-y focal sections taken throughout the height of a VP4-EGFP-expressing cell. EGFP-VP4 fluorescence images were acquired 2 min before photobleaching (Tb − 2 min) and then at 1 min (Tb + 1 min), 6 min (Tb + 6 min), 12 min (Tb + 12 min), 15 min (Tb + 15 min), and 20 min (Tb + 20 min) after photobleaching. Scale bar = 10 μm. This figure is representative of three independent experiments.