Nitrogen starvation in a Saccharomyces cerevisiae strain deleted in the trehalose‐6‐phosphate synthase complex

Little is known about the mechanisms by which nutrient limitation leads to G1 arrest in Saccharomyces cerevisiae. We have shown that mutant cells deleted in the trehalose‐6‐phosphate synthase gene able to grow on glucose, when starved for nitrogen, did not arrest in the G1 phase of the cell cycle. We attribute this effect to an increase in the activity of cAMP‐dependent protein kinase. When grown on maltose without nitrogen they arrested properly in G1. Tests with a mutant cell deleted in the specific trehalose phosphatase proved that the presence of the trehalose precursor, trehalose‐6‐phosphate, was sufficient to trigger the negative sign during nitrogen starvation, leading the cells to arrest in the G1 phase of the cell cycle.