Fig. 5. Fluorescence micrographs of live amoebae expressing (A) EGFP-full length-myosin-II or (B,C) EGFP-myosin-II tail fragment. The cells were flattened under an agar coverslip to reduce superimposition. The direction of movement is indicated with a white arrowhead. (A) Thick filaments labeled with EGFP-full-length-myosin-II concentrate at the trailing edge but are also found throughout the cytoplasm, including a few just behind the leading edge. (B,C) Fluorescence micrographs at 0 and 8 seconds. Intense fluorescent spots interpreted as thick filaments line up along the cell margin of the back half and move steadily backward toward a cluster at the posterior. Small fluorescent spots are interpreted as myosin-II minifilaments. Two white lines serve as positional reference marks. Bar, 10 µm. See corresponding movie online (http://jcs.biologists.org/supplemental).