Fig. 4. NudC downregulation induces mitotic and cytokinetic phenotypes. HeLa cells prepared as in Fig. 3 were analysed for mitotic phenotypes. (A-D) Control siRNA-treated cells in different M phases. (A) Cell in prometaphase. (B) Cell in metaphase. (C) Cleavage-furrow (arrowhead) and midzone microtubules forming during anaphase/telophase. (D) Cell undergoing cytokinesis. (E-K) NudC-siRNA-treated cells. (E) Mitotic spindles appear to be less focused during prometaphase in NudC-siRNA-treated cells. (F) Cells exhibit misaligned chromosome (arrow; see inset) in metaphase. (G) Midzone microtubules are missing (arrowhead) in NudC-siRNA-treated cells in anaphase/telophase. (H,I) Midzone microtubules are missing or disorganized (arrowhead) in cytokinesis. (J,K) Midbody structure is unusually thick or very elongated (arrowhead) between divided cells, suggesting problems in cell separation in NudC-siRNA-treated cells. A much reduced though still detectable level of NudC was observed in NudC-siRNA-treated cells undergoing mitosis. NudC, red; ß-tubulin, green; DNA, blue. Bar, 10 µm in all panels. Scale is the same in A-I.