Synchronization of budding yeast cells.

(A) Illustration of the forced CLN2 expression experiment (reproduced from [7]). Normally, bud formation is driven by CLN1 and CLN2 expression in the budding yeast cell cycle. Daughter cells have longer unbudded periods since they are significantly smaller than the mother cells at birth. Forced periodic expression of CLN2 from the MET3 promoter forces mother and daughter cells to bud earlier compared to unforced conditions. (B) 20 min pulses of CLN2 expression are driven by the periodic activation of the MET3 promoter (period of ). Pink shaded areas show the time intervals during which methionine is removed from the media. Dashed lines indicate the time periods during which the MET3 promoter is actually active in the simulations, taking into account the 16.8 min lag time () reported for this promoter in [17]. We assume the same lag time for MET3 turn-on and turn-off.