FIGURE 2:

Overexpression of SGO1 or SLI15 reduces the chromosome segregation defect in bub1Δ cells without restoring spindle checkpoint function. (A) Strains were grown in liquid culture and analyzed for their ability to arrest in the prolonged presence of the microtubule poison nocodazole. Whereas wild-type cells arrest as large-budded cells, mutants lacking a functional SAC reenter the cycle, which is indicated morphologically by the formation of a second bud. The accumulation of multibudded cells in the bub1Δ strain was unaffected by overexpression of SGO1 or SLI15, indicating that the SAC remains defective. (B) The elevated chromosome loss rate in a haploid bub1Δ strain bearing a YAC, measured by genetic fluctuation test, decreases significantly upon SGO1 or SLI15 overexpression. The experiments were performed at 30°C. *P < 0.05, **P < 0.01, Student’s unpaired t test, two-tailed.