Fig. 7. Mutual exclusion of Citron-K-containing structures and actin cytoskeleton in the equatorial cell cortex during cytokinesis. (A and B) Localization of endogenous Citron-K and F-actin. Two HeLa cells at different stages of cytokinesis were chosen, and stained for endogenous Citron-K (green), F-actin (red), and DNA (blue). Citron-K and F-actin appear to overlap in the very early stage of cytokinesis (A), but are clearly separated in the late stage of cytokinesis (B). (C,D) Localization of GFP-Citron-K (green) and F-actin (red). GFP-Citron-K-expressing HeLa cells undergoing ingression of the cleavage furrow (C) and that at the end stage of cytokinesis (D) were chosen. In C, several confocal sections encompassing the cleavage furrow of a dividing cell are piled up and shown. ß-Tubulin was stained blue in D. Note that GFP-Citron-K and F-actin do not colocalize. Scale bars, 10 µm.