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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).