Figure 2.

SAC inactivation allows SPB separation upon loss of Stu1 function. stu1-5 (ySP1804), stu1-5 mad2Δ (ySP1856), stu1-5 mad3Δ (ySP4595), stu1-5 bub3-WDd1 (ySP6202), and stu1-5 CDC20-107 (ySP6194) mutant cells were arrested in G1 with α-factor at 25°C and released at 37°C (time 0). (A and B) Samples were collected at the indicated times for FACS analysis of DNA contents and to follow kinetics of budding, SPB separation and mitotic spindle formation and elongation. (C) Distribution of distances between SPBs. (D) Micrographs of SPBs were taken 90′ after release. Bar, 2 μm. (E) Examples of microtubules stained by immunofluorescence with anti-tubulin antibodies (time 90′ after release). Bar, 2 μm.