Fig. 1. Influence of apsA and apsB on cytoplasmic and mitotic MTs. (A) Compared with wild type (strain SJW02) (a), where more than three MTs can be observed at the same time, in apsB10-mutant cells (SDV16) (b) only one dominant cytoplasmic MT is apparent. By contrast, the number of cytoplasmic MTs in apsA mutant cells (SNS9) (c) is increased and MTs are more curved and appear thinner. A similar phenotype was observed in a temperature-sensitive dynein mutant strain (SDV26) at restrictive temperature (42°C) (d), while MTs showed wild-type-like organization at permissive temperature (e). (B) Astral MTs (arrowheads) of the mitotic spindle are dramatically reduced in an apsB10 strain (a,d), but not completely lost, in comparison with wild type (b,e). The difference is obvious in short and long spindles. The number of astral MTs was not reduced in apsA strains (c,f). (C,D) Oscillation and movement of the mitotic spindle is common in wild-type strains (C,a-e), but was never observed in a apsA strain (D,a-e). MTs were visualized with a GFP-TubA fusion protein. Dotted lines in (C,D) indicate spindle centers. Bar, 4 µm for (A), 2 µm for (B), 5 µm for (C and D) (see supplementary material Movies 6 and 7).