GSE159575
Dormancy-to-death transition in yeast spores occurs due to gradual loss of gene-expressing ability
Dormancy is colloquially considered as extending lifespan by being still. Starved yeasts  form dormant spores that wake-up (germinate) when nutrients reappear but cannot  germinate (die) after some time. What sets their lifespans and how they age are open  questions because what processes occur - and by how much - within each dormant spore  remains unclear. With single-cell-level measurements, we discovered how dormant yeast  spores age and die: spores have a quantifiable gene-expressing ability during dormancy  that decreases over days to months until it vanishes, causing death. Specifically, each  spore has a different probability of germinating that decreases because its ability to -  without nutrients - express genes decreases, as revealed by a synthetic circuit that forces  GFP expression during dormancy. Decreasing amounts of molecules required for gene  expression - including RNA polymerases - decreases gene-expressing ability which then  decreases chances of germinating. Spores gradually lose these molecules because they  are produced too slowly compared to their degradations, causing gene-expressing ability  to eventually vanish and, thus, death. Our work provides a systems-level view of  dormancy-to-death transition. Overall design: Transcriptome analysis of non-germinated wild-type yeast spores, after exposure to different glucose concentration (0.002% or 0%) in minimal media (SC) at 30C for different amount of time (0h, 16h, 48h, 96h). For each of the 8 different conditions we used 3 biological replicates.