Fig. 6. Expression of non-phosphorylatable AtMAP65-1 delays the metaphase/anaphase transition. (A) Localisation of wild-type GFP:AtMAP65-1 (WT) and mutant GFP:AtMAP65-19A (9A) fusions during mitosis. The wild-type protein becomes associated with microtubules only in anaphase whereas the mutant binds to microtubules at every stage of mitosis. Numbers in the top right corner indicate timing of each frame. (B) Quantification of the fluorescent signal in the cell division midzone of GFP:AtMAP65-1 (closed circles) and GFP:AtMAP65-19A (open circles).