Fig. 4. Dynamics of EGFP-Rab3A and EGFP-Rab27A on newly synthesised secretory granules in PC12 cells. (A-D) PC12 cells were transfected to express the indicated EGFP-tagged protein and examined after 18 hours. Regions of interest (ROIs) in each cell were bleached with high intensity laser (arrows) and the fluorescence recovery of these areas was followed over time. (E) Fluorescence in the ROI was recorded over time during low-intensity imaging. The data are shown as mean ± s.e.m. of 14 ARF1-EGFP, 13 ppANF-EGFP, 21 EGFP-Rab27 and 21 EGFP-Rab3A expressing cells. The data were corrected for general photobleaching for each cell at each time point and normalised by setting the initial fluorescence value for each cell to 100. (F) The data were replotted with the initial post-bleach data point set to 0. Bars, 2 µm.