Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
Proc Natl Acad Sci U S A. 2011 Nov 8;108(45):E1089-98. doi: 10.1073/pnas.1101494108. Epub 2011 Jul 6.
Survival of yeast during starvation has been shown to depend on the nature of the missing nutrient(s). In general, starvation for "natural" nutrients such as sources of carbon, phosphate, nitrogen, or sulfate results in low death rates, whereas starvation for amino acids or other metabolites in auxotrophic mutants results in rapid loss of viability. Here we characterized phenotype, gene expression, and metabolite abundance during starvation for methionine. Some methionine auxotrophs (those with blocks in the biosynthetic pathway) respond to methionine starvation like yeast starving for natural nutrients such as phosphate or sulfate: they undergo a uniform cell cycle arrest, conserve glucose, and survive. In contrast, methionine auxotrophs with defects in the transcription factors Met31p and Met32p respond poorly, like other auxotrophs. We combined physiological and gene expression data from a variety of nutrient starvations (in both respiratory competent and incompetent cells) to show that successful starvation response is correlated with expression of genes encoding oxidative stress response and nonrespiratory mitochondrial functions, but not respiration per se.
酵母在饥饿状态下的存活能力取决于缺失营养物质的性质。一般来说，对于“天然”营养物质（如碳源、磷酸盐、氮源或硫酸盐）的饥饿，死亡率较低，而对于氨基酸或其他代谢物的饥饿，在营养缺陷型突变体中会导致快速丧失生存能力。在这里，我们研究了在蛋氨酸饥饿条件下的表型、基因表达和代谢物丰度。一些蛋氨酸营养缺陷型（生物合成途径受阻的那些）对蛋氨酸饥饿的反应与酵母对磷酸盐或硫酸盐等天然营养物质的饥饿相似：它们经历均匀的细胞周期停滞，保存葡萄糖并存活。相比之下，转录因子 Met31p 和 Met32p 缺陷的蛋氨酸营养缺陷型反应较差，与其他营养缺陷型相似。我们将来自各种营养饥饿（在呼吸能力强和弱的细胞中）的生理和基因表达数据进行了组合，表明成功的饥饿反应与编码氧化应激反应和非呼吸线粒体功能的基因表达相关，但与呼吸本身无关。
