FIGURE 5.

Mps1 overexpression-induced phenotypes. A, accumulation of large amounts of Mps1 in ufd2Δ cells delays cell cycle progression. Wild-type or ufd2Δ cells were arrested in G₂/M by nocodazole (Noc) for 4 h. Cells were released from the arrest after the removal of nocodazole, and samples taken at various time points after the release were subject to FACScan analysis of DNA content. In the two lower panels, Mps1-Myc expression was induced for 2 h with the addition of galactose and was repressed with glucose as cells were released from the G₂/M block. Representative FACS results are shown. OE, overexpression. B, plating efficiency of wild-type or ufd2Δ mutant cells that transiently overexpressed Mps1. Mid-log phase yeast cells were split in two sets: one set was kept unperturbed, the second set was treated with galactose for 1.5 or 3 h to transiently induce Mps1 expression. Equal numbers of cells were plated on glucose-containing medium to repress Mps1 overexpression. The percentage of yeast cells that formed colonies after Mps1 induction was determined. Values shown are derived from three independent experiments.