Mitotic progression of cells containing <i>CDC55</i>, <i>CLB2</i> and <i>BUB2</i> mutations.

<p>(<b>A</b>) In the <i>CDC55</i> deletion strain, Cdc14 is re-sequestered with a delay. Cdc20 block-and-release was simulated as usual, with [PP2A]_total = 0. (<b>B</b>) Cdc14 is released prematurely in <i>bub2Δ</i> cells. Cdc20 block-and-release was pre-simulated with the rates of Tem1 inactivation by Cdc14 and PP2A set to zero (<i>k</i>_i,tem′ = <i>k</i>_i,tem″ = 0). (<b>C</b>) In a nocodazole-arrested cell, overexpression of Clb2 induces Cdc14 release, and the cell arrests in telophase. Pre-simulation was done by setting <i>N</i> = 1 for 15 min. At <i>t</i> = 0, the rate of synthesis of Clb2 was increased 20-fold and the rates of degradation of Clb2 were set to zero (<i>N</i> = 1, <i>k</i>_d,b2′ = <i>k</i>_d,b2″ = 0, <i>k</i>_s,b2 = 0.6). (<b>D</b>) Cdc14 is not released when Clb2 is overexpressed in G1 cells with Cdc5 inactive. This simulation was started from G1 initial conditions (low levels of Clb2, Cdc5 and Cdc14). At <i>t</i> = 0, the initial condition of Polo is set to 0.01, the synthesis rate of Clb2 is set to a large value and its degradation rate is set to zero (<i>k</i>_d,b2′ = <i>k</i>_d,b2″ = <i>k</i>_s,polo = 0, <i>k</i>_s,b2 = 0.6).