Fig. 5. Time-lapse images of localization of WAVE isoforms tagged with EGFP in the growth cone. (A,B) WAVE1-EGFP localized along the leading edge and concentrated in the extending region (asterisk) but disappeared in the retracting region (indicated by square bracket). Neither was found at the filopodial tips (arrows). The upper panel (A) shows fluorescence images of WAVE1-EGFP, whereas the lower panel (B) shows differential interference contrast (DIC) images corresponding to the upper images. The four columns show the image every 44 seconds. (C,D) WAVE2-EGFP condensed as dot-like spots at the sites where microspikes encounter the leading edge (arrowheads). They correspond to the tips of filopodia and project extracellularly with elongation (open arrows). WAVE2-EGFP remained at the tips of extending filopodia (open arrows) and sometimes moved with time laterally along the leading edge with the lateral motion of actin bundles through the lamellipodium (arrowheads). By contrast, WAVE2-EGFP spots disappeared at the tips of retracting filopodia in the region indicated by square brackets. The upper panel (C) shows fluorescence images from WAVE2-EGFP at the growth cone and the lower panel (D) indicates the corresponding DIC images. (E,F) WAVE3-EGFP localized at the tips of extending filopodia and remained there during elongation (arrowheads), and also distributed along the leading edge of extending lamellipodia (asterisks). The upper panel (E) shows fluorescence images of the WAVE3-EGFP distribution at the growth cone and the lower panel (F) shows the corresponding DIC images. Bar, 1 µm.