MT minus end dynamics in the absence of functional Asp. (A) Scattered MT minus ends at the polar region in the absence of functional Asp, as visualized by AspΔC-GFP expression. Endogenous Asp was depleted by RNAi. (B) Control full-length Asp(FL)-GFP at the pole. A giant cluster of GFP signals was observed at each pole because of MT focusing. (C–E) Behavior of the minus end of the outermost MT bundle in the spindle. In the absence of functional Asp (C and E), the minus end was translocated to the polar region without coalescence with other MTs. With functional Asp, such MTs were merged with adjacent MTs during translocation (D and E). Arrowheads indicate the minus ends of the outermost MT bundle, whereas arrows indicate the pole. Time is displayed in minutes/seconds. Bars: (A–D) 5 µm; (C and D, bottom) 2 µm.