Figure 7.
Instability of Cdc13 in mcs1-77 cells is due to the activity of APCSte9 (A) Deletion of Ste9/Srw1 rescues the cell cycle delay in mcs1-77 cells. mcs1-77 cdc25-22 or ste9::ura4 mcs1-77 cdc25-22 cells were grown on YEPD at 25°C and then streaked onto YEPD plates at either 25 or 31°C, and the growth of the strains was monitored after 3 d at these temperatures. (B) Deletion of Ste9 stabilizes Cdc13 cyclin B in mcs1-77 cells. Log-phase cultures of either mcs1-77 cdc25-22 or ste9::ura4 mcs1-77 cdc25-22 cells growing in YEPD at 28°C were shifted to 35.5°C for 3 h and then incubated in the same medium containing 100 μg/ml cycloheximide at 35.5°C for the times indicated. Cell extracts were prepared and probed for the presence of Cdc13 with the use of affinity-purified anti-Cdc13 polyclonal antibodies.