Fig. 4. (A) Dynamic change of cytoc-GFP distribution (unbroken line) and average mitochondrial diameter (broken line) in a single living cell during UV-induced apoptosis. Data are based on analysis of images obtained from the upper cell shown in Fig. 2. F_mito/F_cyto represents the fluorescence ratio of cytoc-GFP between mitochondria and cytoplasm. (B) Time-dependent changes of cytoc-GFP distribution and mitochondrial diameter as measured from a single mitochondrion (marked by arrowhead in Fig. 2D,E).