Dynamics of SIN Asymmetry Establishment
Figure 5
Predictions and experimental tests on collective effects of multiple mutations on SIN asymmetry establishment timing.
(A–C) Simulations of interactions of cdc16ts (A) and cdc16ts sip− (C) mutations with mutations in cdc11 phosphorylation sites. Reduced level of Cdc16 activity was simulated by the indicated reduction in Byr4 efficiency on SIN inactivation. Mutations in SIP was captured by 25% reduction in both ppC and ppS efficiency. As shown on Fig. 4 we assume that 50% SIN efficiency corresponds to the cdc11-S5A mutation. Time courses of Byr4 level changes at the old SPB are plotted as a representative proxy of SIN asymmetry establishment (other variables follow this as on Fig. 3). (B–D) Spot assays: The indicated cultures were serially diluted and spotted on YES agar medium, and grown at the specified temperatures. (B) At 32°C cdc11-S8A can partially compensate effects of the temperature sensitive cdc16-116 mutation, while cdc11-S5A makes it even more severe. (D) cdc11-S5A decreases while cdc11-S8A minimally increases viability of cdc16ts sip− mutants. (E) Phenotypes observed in the colonies of panel D at 25°C. n>300 cells for each strain.