Modeling the Budding Yeast Cell Cycle

CLB5-db∆ sic1∆

Simulation:

Change of parameters: kdb5"=0, ksc1'=ksc1"=0.
Arrest: It dies after the first cycle, Ori not relicensed.

Experiments:

Jacobson, M.D., Gray, S., Yuste-Rojas, M. and Cross, F.R. (2000). Testing cyclin specificity in the exit from mitosis. Mol. Cell. Biol. 20:4483-4493.
[Abstract] [Article]
Wasch, R. and Cross, F. (2002). APC-dependent proteolysis of the mitotic cyclin Clb2 is essential for mitotic exit. Nature 418:556-562.
[Abstract] [Article]
Experimental results: Wasch, Fig. 2. It has similar phenotype as sic1∆ cdh1∆ being semi-lethal on glucose medium. Mutant cell arrests with replicated but un-separated DNA without long mitotic spindle. It showa a high rate of loss for plasmids containing single replication origin, but the rate of loss is significantly decreased for multi-origin plasmids. This indicates that the mutant is not blocked from mitotic exit, but it has problems with origin usage.
Comments: In simulation, the mutant is able to exit the first mitosis, but dies because of DNA replication problem. [ORI] (grey line) is not re-licensed after the first mitosis.