Fig. 7

Enhanced-GFP kinesin-like protein (kif23-EGFP) localization during cytokinesis in zebrafish embryos. Kif23-EGFP is indicated in green and rhodamine–tubulin labeling is in red. Panels Ai to Av illustrate a time-series of kif23-EGFP recruitment to the cleavage furrow during deepening of the 3rd cell division cycle. Panel Avi shows a magnified view of the region indicated with a white box in panel Aii, which suggests that kif23-EGFP is colocalized with microtubules. Kif23-EGFP recruitment to the future cleavage plane begins at anaphase (see panel B) and lasts through telophase (see panel C) and interphase (see panel D), at which time the furrow undergoes apposition. During interphase, microtubule bundling is temporally and spatially associated with the convergence of kif23-EGFP fluorescence into a spot, which is located between adjacent daughter cells. This process is illustrated in a time-series (see panels Dii to Div) taken from the area indicated by the white box shown in panel Di. During the late Cleavage Period of zebrafish development, many kif23-EGFP spots can be seen between daughter cells (see white arrowheads in panel E). Panels F and G illustrate the ring-like localization of kif23-EGFP surrounding the microtubule bundle that still connects daughter cells during the late stage of cytokinesis. The ring-like structure eventually constricts leaving a characteristic single kif23-EGFP spot between daughter cells, as illustrated in panel Div.