Genetic and Molecular Analysis of Division Control in Yeast

In Saccharomyces, cell division is controlled both in response to nutrient limitation (Byers and Goetsch 1975; Johnston et al. 1977) and by mating pheromones in preparation for sexual conjugation (Bücking-Throm et al. 1973). In each case, control of division occurs late in the G1 interval of the cell cycle. This has led to the proposal of an integrative gating event for cell division designated as “start” (Hartwell et al. 1974). It has been our goal, using genetic and molecular methods, to describe “start” in molecular terms, and in so doing, to define the biochemical mechanism of division control in a eukaryotic organism.