Overexpression profiling reveals cellular requirements in the context of genetic backgrounds and environments

Overexpression can help life adapt to stressful environments, making an examination of overexpressed genes valuable for understanding stress tolerance mechanisms. However, a systematic study of genes whose overexpression is functionally adaptive (GOFAs) under stress has yet to be conducted. We developed a new overexpression profiling method and systematically identified GOFAs in Saccharomyces cerevisiae under stress (heat, salt, and oxidative). Our results show that adaptive overexpression compensates for deficiencies and increases fitness under stress, like calcium under salt stress. We also investigated the impact of different genetic backgrounds on GOFAs, which varied among three S. cerevisiae strains reflecting differing calcium and potassium requirements for salt stress tolerance. Our study of a knockout collection also suggested that calcium prevents mitochondrial outbursts under salt stress. Mitochondria-enhancing GOFAs were only adaptive when adequate calcium was available and non-adaptive when calcium was deficient, supporting this idea. Our findings indicate that adaptive overexpression meets the cell's needs for maximizing the organism's adaptive capacity in the given environment and genetic context. Author summaryThe study aimed to investigate how overexpression of genes can aid organisms in adapting to stress. The researchers utilized a new method to identify genes in yeast that demonstrated functional adaptability when overexpressed under stress such as heat, salt, and oxidative stress. The results indicated that overexpressing specific genes, like calcium, during salt stress could counteract deficiencies and improve the organism's ability to withstand stress. The study also examined the effect of different genetic backgrounds on these genes and discovered that the impact differed among various yeast strains. Additionally, the study revealed that calcium could play a key role in adapting to salt stress by preventing mitochondrial outbursts. These findings suggest that overexpressing certain genes can help the organism maximize its adaptability to stress in a given environment and genetic context.