Fig. 3. ARF6 is required for rapid cleavage furrow invagination. (A) Representative results for control, arf6 mutant `early regressor', `late regressor' and chic^13E illustrate furrow progression, timing of Pavarotti concentration at central spindle (arrowheads) and indented cleavage furrow appearance (arrows). Diameter is measured at furrow tip or future furrow site. (B) Furrow ingression rates in control (black), arf6 late regressors (blue) chic^13E (green) and arf6 early regressors (red). Furrow ingression is significantly impaired in arf6 mutants compared with control cells: ^*P<0.01, Student's t-test. min AA, minutes after anaphase onset.